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ART002112870
|
oai_dc
|
Assessment of strength and durability of bagasse ash and Silica fume concrete
|
Assessment of strength and durability of bagasse ash and Silica fume concrete
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jayanthi Singaram(Department of Civil Engineering Government College of Technology); Radhika Kowsik(University Maduravoyal)"
] |
An alternative type of building system with masonry units is extensively used nowadays to reduce the emission of CO2 and embodied energy. Long-term performance of such structures has become essential for sustaining the building technology. This study aims to assess the strength and durability properties of concrete prepared with unprocessed bagasse ash (BA) and silica fume (SF). A mix proportion of 1:3:3 was used to cast concrete cubes of size 100 mm×100 mm×100 mm with various replacement levels of cement and tested. The cubes were cast with zero slump normally adopted in the manufacturing of hollow blocks. The cubes were exposed to acid attack, alkaline attack and sulphate attack to evaluate their durability.
The mass loss and damages to concrete for all cases of exposures were determined at 30, 60, and 90 days, respectively. Then, the residual compressive strength for all cases was determined at the end of 90 days of durability test. The results showed that there was slight difference in mass loss before and after exposure to chemical attack in all the cases. Though the appearance was slightly different than the normal concrete the residual weight was not affected. The compressive strength of 10% bagasse ash (BA) as a replacement for cement, with 10% SF as admixture resulted in better strength than the normal concrete. Hence concrete with 10% replacement with BA along with 10% SF as admixture was considered to be durable. Besides solid concrete cubes, hollow blocks using the same concrete were casted and tested simultaneously to explore the possibility of production of masonry units.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002112858
|
oai_dc
|
Layered model of aging concrete. General concept and one-dimensional applications
|
Layered model of aging concrete. General concept and one-dimensional applications
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Andrzej Truty(Cracow University of Technology); Jan Szarlinski(Cracow University of Technology); Krzysztof Podles(Cracow University of Technology)"
] |
A novel approach to modeling concrete behavior at the stage of its maturing is presented in this paper. This approach assumes that at any point in the structure, concrete is composed of a set of layers that are activated in time layer by layer, based on amount of released heat that is produced during process of the concrete’s maturing. This allows one to assume that each newly created layer has nominal stiffness moduli and tensile/compressive strengths. Hence introduction of explicit stiffness moduli and tensile/compressive strength dependencies on time, or equivalent time state parameter, is not needed. Analysis of plain concrete (PC) and reinforced concrete (RC) structures, especially massive ones, subjected to any kind of straining in their early stage of existence, mostly due to external loads but especially by thermal loading and shrinkage, is the goal of the approach. In this article a simple elasto-plastic softening model with creep is used for each layer and a general layered model behavior is illustrated on one-dimensional (1D) examples.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002112873
|
oai_dc
|
Effect of the PC, diatomite and zeolite on the performance of concrete composites
|
Effect of the PC, diatomite and zeolite on the performance of concrete composites
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yilmaz Kocak(Dumlupinar University); Muhsin Savas(Duzce University)"
] |
This study has been carried out to investigate the effect of the surface properties of Portland cement, diatomite and zeolite on the performance of concrete composites. In this context, to describe the materials used in this study and determine the properties of them, chemical, physical, mineralogical, molecular, thermal, and zeta potential analysis have been applied. In the study, reference (Portland cement), 10%–20% diatomite, 10%–20% zeolite, 5+5%–10+10% diatomite and zeolite were substituted for Portland cement, a total of 7 different cements were obtained. Ultrasonic pulse velocity, capillary water absorption and compressive strength tests were performed on the hardened concrete specimens. Hardened concrete tests have been done on seven different types of concrete, for 28, 56 and 90 days. As a result of experiments it has been identified that both the zeolite and diatomite substitution has a positive effect on the performance of concrete.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002112863
|
oai_dc
|
Analysis of punching shear in high strength RC panels– experiments, comparison with codes and FEM results
|
Analysis of punching shear in high strength RC panels– experiments, comparison with codes and FEM results
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ahmed B. Shuraim(King Saud University); Fahid Aslam(King Saud University); Raja R. Hussain(King Saud University); Abdulrahman M. Alhozaimy(King Saud University)"
] |
This paper reports on punching shear behavior of reinforced concrete panels, investigated experimentally and through finite element simulation. The aim of the study was to examine the punching shear of high strength concrete panels incorporating different types of aggregate and silica fume, in order to assess the validity of the existing code models with respect to the role of compressive and tensile strength of high strength concrete. The variables in concrete mix design include three types of coarse aggregates and three water-cementitious ratios, and ten-percent replacement of silica fume. The experimental results were compared with the results produced by empirical prediction equations of a number of widely used codes of practice. The prediction of the punching shear capacity of high strength concrete using the equations listed in this study, pointed to a potential unsafe design in some of them. This may be a reflection of the overestimation of the contribution of compressive strength and the negligence of the role of flexural reinforcement. The overall findings clearly indicated that the extrapolation of the relationships that were developed for normal strength concrete are not valid for high strength concrete within the scope of this study and that finite element simulation can provide a better alternative to empirical code Equations.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002112881
|
oai_dc
|
Multiple cracking analysis of HTPP-ECC by digital image correlation method
|
Multiple cracking analysis of HTPP-ECC by digital image correlation method
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Burak Felekoglu(Dokuz Eylul University); Muhammer Keskinates(Dokuz Eylul University)"
] |
This study aims to characterize the multiple cracking behavior of HTPP-ECC (High tenacity polypropylene fiber reinforced engineered cementitious composites) by Digital Image Correlation (DIC) Method. Digital images have been captured from a dogbone shaped HTPP-ECC specimen exhibiting 3.1% tensile ductility under loading. Images analyzed by VIC-2D software and εxx strain maps have been obtained. Crack widths were computed from the εxx strain maps and crack width distributions were determined throughout the specimen. The strain values from real LVDTs were also compared with virtual LVDTs digitally attached on digital images. Results confirmed that it is possible to accurately monitor the initiation and propagation of any single crack or multiple cracks by DIC at the whole interval of testing.
Although the analysis require some post-processing operations, DIC based crack analysis methodology can be used as a promising and versatile tool for quality control of HTPP-ECC and other strain hardening composites.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002013635
|
oai_dc
|
Comparison of linear and non-linear earthquake response of masonry walls
|
Comparison of linear and non-linear earthquake response of masonry walls
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Erkut Sayın(Fırat University); Yusuf Calayır(Fırat University)"
] |
In this study, linear and non-linear response of a masonry wall that includes an opening was presented. The masonry wall was modeled with two-dimensional finite elements. Smeared crack model that includes the strain softening behavior was selected to the masonry wall material. For the numerical application, linear and non-linear analyses of the masonry wall were carried out using east-west and vertical components of the 1992 Erzincan and 2003 Bingöl earthquake acceleration records. Linear and non-linear solutions were compared each other. The displacement and stress results at the selected points of the masonry wall and crack propagation in the masonry wall were presented for both earthquake acceleration records.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002013636
|
oai_dc
|
Modeling the alkali aggregate reaction expansion in concrete
|
Modeling the alkali aggregate reaction expansion in concrete
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Sekrane Nawal Zahira(Djillali Liabes University); Asroun Aissa(Djillali Liabes University)"
] |
Alkali aggregate reaction affects numerous civil engineering structures and causes irreversible expansion and cracking. This work aims at developing model to predict the potential expansion of concrete containing alkali-reactive aggregates. First, the paper presents the experimental results concerning the influence of particle size of an alkali-reactive aggregate on mortar expansion studied at 0.15–0.80 mm, 1.25–2.50 mm and 2.5–5.0 mm size fractions and gives data necessary for model development. Results show that no expansion was measured on the mortars using small particles (0.15-0.80 mm) while the particles (1.25–2.50 mm) gave the largest expansions. Finally, model is proposed to simulate the experimental results by studying correlations between the measured expansions and the size of aggregates and to calculate the thickness of the porous zone necessary to take again all the volume of the gel created by this chemical reaction.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002013722
|
oai_dc
|
Fragility assessment of RC-MRFs under concurrent vertical-horizontal seismic action effects
|
Fragility assessment of RC-MRFs under concurrent vertical-horizontal seismic action effects
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ehsan Noroozinejad Farsangi(International Institute of Earthquake Engineering); Abbas Ali Tasnimi(Tarbiat Modares University (TMU)); Babak Mansouri(International Institute of Earthquake Engineering and Seismology (IIEES))"
] |
In this study, structural vulnerability of reinforced concrete moment resisting frames (RC-MRFs) by considering the Iran–specific characteristics is investigated to manage the earthquake risk in terms of multicomponent seismic excitations. Low and medium rise RC-MRFs, which constitute approximately 80-90% of the total buildings stock in Iran, are focused in this fragility–based assessment.
The seismic design of 3-12 story RC-MRFs are carried out according to the Iranian Code of Practice for Seismic Resistant Design of Buildings (Standard No. 2800), and the analytical models are formed accordingly in open source nonlinear platforms. Frame structures are categorized in three subclasses according to the specific characteristics of construction practice and the observed seismic performance after major earthquakes in Iran. Both far and near fields’ ground motions have been considered in the fragility estimation. An optimal intensity measure (IM) called Sa, avg and beta probability distribution were used to obtain reliable fragility–based database for earthquake damage and loss estimation of RC buildings stock in urban areas of Iran. Nonlinear incremental dynamic analyses by means of lumped-parameter based structural models have been simulated and performed to extract the fragility curves. Approximate confidence bounds are developed to represent the epistemic uncertainties inherent in the fragility estimations. Consequently, it’s shown that including vertical ground motion in the analysis is highly recommended for reliable seismic assessment of RC buildings.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002013752
|
oai_dc
|
A treatise on irregular shaped concrete test specimens
|
A treatise on irregular shaped concrete test specimens
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Selçuk Emre Görkem(Erciyes University)"
] |
An experimental program has been carried out to investigate the effect of edge-slope on compressive strength of concrete specimens. In this study, effect of such slope was investigated by testing 100 standard cylinder specimens and 40 standard cubes. When molds are put on a slanted place, wet concrete starts to flow through the open end of mold. It keeps flowing until it reaches to a parallel surface with the place over which it was placed. That creates a sloped surface over the loading area. Experimental results revealed significant relationships between failure loads and slope of loading surface for cylinders. Angled cracks occurred in sloped cylinder specimens. Tension cracks occurred in cube specimens. Fracture mechanisms were also evaluated by using finite element analyses approach. Experiments yielded an exponential curve with bandwidth for cylinders. Average value of curve is between slope and compressive strength. Inclination is much effective parameter for cylinders than cubes.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002013751
|
oai_dc
|
Study on the behavior of beam-column connection in precast concrete structure
|
Study on the behavior of beam-column connection in precast concrete structure
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Marcela N. Kataoka(University of São Paulo); Marcelo A. Ferreira(Federal University of São Carlos); Ana Lúcia H.C. El Debs(University of São Paulo)"
] |
Due to the increase of the use of precast concrete structures in multistory buildings, this paper deals with the behavior of an specific type of beam-column connection used in this structural system. The connection is composed by concrete corbels, dowels and continuity bars passing through the column. The study was developed based on the experimental and numerical results. In the experimental analysis a full scale specimen was tested and for numerical study, a 3D computational model was created using a finite element analyze (FEA) software, called DIANA. The comparison of the results showed a satisfactory correlation between loading versus displacement curves.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002013720
|
oai_dc
|
Analysis and monitoring on jacking construction of continuous box girder bridge
|
Analysis and monitoring on jacking construction of continuous box girder bridge
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Fangyuan Li(Tongji University); Peifeng Wu(Tongji University); Xinfei Yan(Shanghai Urban Construction Design & Research Institute)"
] |
It is hard to guarantee the strict synchronization of all the jacking-up points in the integral jacking of a large-span continuous box girder bridge. This paper took the Hengliaojing Bridge as background, which need jacking up as an object with 295m length and more than 10,000tons weight, adopted 3D software to calculate the unsynchronized jacking-up working conditions, and studied the relationships between the unsynchronized vertical difference and the girder’s deformation behaviour.
The aim is to verify the maximum value of the unsynchronized vertical difference, and guide the construction and ensure safety. The monitoring system with its contents is introduced corresponding to the analysis. The results of the deck relative elevations prove that it is difficult to avoid the deck torsional deformation for jacking different; especially the side span shows more deformations for its smaller stiffness. The maximum difference is smaller than the limited value with acceptable stresses in the sections. The jacking heights of the pier in each construction step are controlled regularly according to the design. The shifting of the whole bridge in longitudinal direction is smaller than in transverse direction. The several beginning steps are the key to adjust their support reactions. This study is one parts of the fundamental research for the code “Technical specification for bridge jacking-up and reposition of China”. The whole synchronous jacking project of the main bridge set a world record by the World Record Association for the whole bridge jacking project with the longest span of the world.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002013750
|
oai_dc
|
Investigation of the effect of weak-story on earthquake behavior and rough construction costs of RC buildings
|
Investigation of the effect of weak-story on earthquake behavior and rough construction costs of RC buildings
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Şenol Gürsoy(Karabük University); Ramazan Öz(Karabük University); Selçuk Baş(Bartın University)"
] |
A significant portion of residential areas of Turkey is located in active earthquake zones. In Turkey occurred major earthquakes in last twenty years, such as Erzincan (1992), Kocaeli and Düzce (1999), Bingöl (2003), Van (2011). These earthquakes have demonstrated that reinforced concrete (RC) buildings having horizontal and vertical irregularities are significantly damaged, which in turn most of them are collapsed. Architectural design and arrangement of load-bearing system have important effect on RC building since architectural design criteria in design process provide opportunity to make this type of buildings safer and economical under earthquake loads. This study aims to investigate comparatively the effects of weak story irregularity on earthquake behavior and rough construction costs of RC buildings by considering different soil-conditions given in the Turkish Earthquake Code. With this aim, Sta4-CAD program based on matrix displacement method is utilized. Considering that different story height and compressive strength of concrete, and infill walls or their locations are the variables, a set of structural models are developed to determine the effect of them on earthquake behavior and rough construction costs of RC buildings. In conclusion, some recommendations and results related to making RC buildings safer and more economical are presented by comparing results obtained from structural analyses.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002013721
|
oai_dc
|
Ultimate torsional behaviour of axially restrained RC beams
|
Ultimate torsional behaviour of axially restrained RC beams
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Luís F.A. Bernardo(University of Beira Interior); Cátia S.B. Taborda(University of Beira Interior); Jorge M.A. Andrade(University of Beira Interior)"
] |
This article presents a computing procedure developed to predict the torsional strength of axially restrained reinforced concrete beams. This computing procedure is based on a modification of the Variable Angle Truss Model to account for the influence of the longitudinal compressive stress state due to the axial restraint conditions provided by the connections of the beams to other structural elements.
Theoretical predictions from the proposed model are compared with some experimental results available in the literature and also with some numerical results from a three-dimensional nonlinear finite element analysis. It is shown that the proposed computing procedure gives reliable predictions for the ultimate behaviour, namely the torsional strength, of axially restrained reinforced concrete beams under torsion.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002013634
|
oai_dc
|
Finite element analysis of longitudinal reinforcement beams with UHPFC under torsion
|
Finite element analysis of longitudinal reinforcement beams with UHPFC under torsion
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Thaer Jasim Mohammed(Universiti Sains Malaysia); B.H. Abu Bakar(Universiti Sains Malaysia); N. Muhamad Bunnori(Universiti Sains Malaysia); Omer Farouk Ibraheem(University Sains Malaysia (USM))"
] |
The proposed techniques to strengthen concrete members such as steel plates, polymers or concrete have important deficiencies in adherence and durability. The use of UHPFC plates can overtake effectively these problems. In this paper, the possibility of using UHPFC to strengthen RC beams under torsion is investigated. Four specimens of concrete beams reinforced with longitudinal bars only were tested under pure torsion. One of the beams was considered as the baseline specimen, while the others were strengthened by ultra-high-performance fiber concrete (UHPFC) on two, three, and four sides.
Finite element analysis was conducted in tandem with experimental work. Results showed that UHPFC enhances the strength, ductility, and toughness of concrete beams under torsional load, and that finite element analysis is in good agreement with the experimental data.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002013749
|
oai_dc
|
Microstructural modelling of the elastic properties of tricalcium silicate pastes at early ages
|
Microstructural modelling of the elastic properties of tricalcium silicate pastes at early ages
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Huy Q. Do(Ecole Polytechnique Fédérale de Lausanne); Shashank Bishnoi(Indian Institute of Technology Delhi); Karen L. Scrivener(Ecole Polytechnique Fédérale de Lausanne)"
] |
This paper describes the numerical calculation of elastic properties of a simulated microstructure of cement paste from very early age, when most previous models fail to give accurate results. The development of elastic properties of tricalcium silicate pastes was calculated by discretising a numerical resolution-free 3D vector microstructure to a regular cubic mesh. Due to the connections formed in the microstructure as an artefact of the meshing procedure, the simulated elastic moduli were found to be higher than expected. Furthermore, the percolation of the solids was found to occur even before hydration started. A procedure to remove these artefacts, on the basis of the information available in the vector microstructures was developed. After this correction, a better agreement of the experimental results with calculations was obtained between 20% and 40% hydration. However, percolation threshold was found to be delayed significantly. More realistic estimates of percolation threshold were obtained if either flocculation or a densification of calcium silicate hydrate with hydration was assumed.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002000433
|
oai_dc
|
Multiscale modeling for compressive strength of concrete columns with circular cross-section
|
Multiscale modeling for compressive strength of concrete columns with circular cross-section
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Han-liang Wu(Beijing Jiaotong University); Yuan-Feng Wang(Beijing Jiaotong University)"
] |
In order to construct a multiscale model for the compressive strength of plain concrete columns with circular cross section subjected to central longitudinal compressive load, a column failure mechanism is proposed based on the theory of internal instability. Based on an energy analysis, the multiscale model is developed to describe the failure process and predict the column’s compressive strength. Comparisons of the predicted results with experimental data show that the proposed multiscale model can accurately represent both the compressive strength of the concrete columns with circular cross section, and the effect of column size on its strength.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002000543
|
oai_dc
|
Influence of curing condition and carbonation on electrical resistivity of concrete
|
Influence of curing condition and carbonation on electrical resistivity of concrete
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"윤인석(인덕대학교); 홍성원(서울대학교); 강현구(서울대학교)"
] |
The electrical resistivity of air-dried, saturated, and carbonated concretes with different mixture proportions was monitored to evaluate and quantify the influence of the age of the specimen, carbonation, and curing condition. After 28 days of curing, four prepared specimens were stored in a vacuum chamber with 5% CO2 for 330 days to make carbonated specimens. Four of the specimens were placed in water, and four specimens were cured in air until the end of the experiments. It was observed that the electrical resistivity of the carbonated specimens increased as carbonation progressed due to the decrease of porosity and the increase of hydrated products. Therefore, in order to estimate the durability of concrete, its carbonation depth was used as the measurement of electrical resistivity. Moreover, an increase of electrical resistivity for air-dried and saturated concretes was observed as a function of age of the specimen. From the relationship between chloride diffusivity provided by Yoon et al. (2007) and the measurements of electrical resistivity, it is expected that the results well be of significant use in calibrating chloride diffusivity based on regular measurements of electrical resistivity during concrete construction.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002000474
|
oai_dc
|
Compressive, shear and torsional strength of beams made of self-compacting concrete
|
Compressive, shear and torsional strength of beams made of self-compacting concrete
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Moosa Mazloom(Shahid Rajaee Teacher Training University); Amirali Saffari(Shahid Rajaee Teacher Training University); Morteza Mehrvand(University of Science and Culture)"
] |
The aim of this study is to provide experimental data regarding the compressive, shear and torsional strength of self-compacting concrete (SCC) used in rectangular beams, and then comparing the results with the equations presented by the CSA A23.3-04 and ACI 318-11. In fact, the gathered information in this field is quite useful for calibrating the computer models of other researchers. The other goal of this study was to investigate the effects of silica fume and superplasticizer dosages on the mechanical properties of SCC. In this research, SCC is made based on 16 different type mixing layout. Also two normal concrete (NC) or vibrating concrete are constructed to compare the results of SCC and NC. This work concentrated on concrete mixes having water/binder ratios of 0.45 and 0.35, which contained constant total binder contents of 400 kg/m3 and 500 kg/m3, respectively. The percentages of silica fume that replaced cement were 0% and 10%. The superplasticizer dosages utilized in the mixtures were 0.4%, 0.8%, 1.2% and 1.6% of the weight of cement. Beam dimensions used in this test were 30×30×120 cm3.The results of this research indicated that shear and torsional strength of SCC beams to be used in computer models can be calculated utilizing the equations presented in CSA A23.3-04 and ACI 318-11.
Keywords: self-compacting concrete; rectangular beam; shear strength
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002000460
|
oai_dc
|
Sensitivity and accuracy for rheological simulation of cement-based materials
|
Sensitivity and accuracy for rheological simulation of cement-based materials
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"김재홍(울산과학기술원); 장혜림(울산과학기술원); 임홍재(경북대학교)"
] |
The flow of freshly mixed cement-based material shows thixotropy, which implies some difficulties on robust measurement of its rheological properties: The flow curve of thixotropic materials depends on the used protocol. For examples, higher viscosity is obtained when the rate of shear strain is more quickly increased. Even though precise measurement and modelling of the concrete rheology needs to consider the thixotropic effect, engineers in the concrete field prefer considering as a non-thixotropic Herschel-Bulkley fluid, even more simply Bingham fluid. That is due to robustness of the measurement and application in casting process. In the aspect of simplification, this papers attempts to mimic the thixoropic flow by the non-thixotropic Herschel-Bulkley model.
Disregarding the thixotropy of cement based materials allows us to adopt the rheological concept in the field. An optimized protocol to measure the Bingham parameters was finally found based on the accuracy and reproducibility test of cement paste samples, which minimizes the error of simulation stemming from the assumption of non-thixotropy.
Keywords: cement
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002000549
|
oai_dc
|
An advanced single-particle model for C3S hydration - validating the statistical independence of model parameters
|
An advanced single-particle model for C3S hydration - validating the statistical independence of model parameters
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Joseph J. Biernacki(Tennessee Technological University Cookeville); Manohar Gottapu(Tennessee Technological University)"
] |
An advanced continuum-based multi-physical single particle model was recently introduce for the hydration of tricalcium silicate (C3S). In this model, the dissolution and the precipitation events are modeled as two different yet simultaneous chemical reactions. Product precipitation involves a nucleation and growth mechanism wherein nucleation is assumed to happen only at the surface of the unreacted core and product growth is characterized via a two-step densification mechanism having rapid growth of a low density initial product followed by slow densification. Although this modeling strategy has been shown to nicely mimic all stages of C3S hydration – dissolution, dormancy (induction), the onset of rapid hydration, the transition to slow hydration and prolonged reaction – the major criticism is that many adjustable parameters are required. If formulated correctly, however, the model parameters are shown here to be statistically independent and significant.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002000467
|
oai_dc
|
Earthquake performance investigation of R/C residential buildings in Turkey
|
Earthquake performance investigation of R/C residential buildings in Turkey
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Kasim Armagan Korkmaz(Istanbul Technical University,); Fuat Demir(Süleyman Demirel University); Tugce Yenice(Suleyman Demirel University)"
] |
The aim of this study is to determine the earthquake performances of reinforced concrete (R/C) residential buildings in Turkey and to analyze the parameters that affect the performance. The performance of Turkish residential buildings, determined by their levels of damage, directly relates to their structural systems.
Damage parameters observed from previous earthquakes define structural parameters selected to be used in the present study. Five different types of frame R/C buildings were modeled. For the analysis, the model buildings vary according to the number of stories, column sizes, and reinforcement and concrete strength parameters. The analyses consider gravity forces and earthquake loads through 1975 and 2007 Turkish design codes. In a total of 720 different R/C buildings were investigated for the analysis to obtain capacity curves. A performance evaluation was employed by considering the Turkish design code (TDC-2007). The current study ignores irregularities such as soft stories or short columns. The study’s analysis considers a comparison of the parameters’ influence on the structural performance of the model buildings.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002000447
|
oai_dc
|
Remaining service life estimation of reinforced concrete buildings based on fuzzy approach
|
Remaining service life estimation of reinforced concrete buildings based on fuzzy approach
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"조해창(서울시립대학교); 이득행(서울시립대학교); 주현진(서울시립대학교 건축학부); 김강수(서울시립대학교); 김기현(서던캘리포니아대학교); Paulo J. M. Monteiro(University of California at Berkeley)"
] |
The remaining service life (RSL) of buildings has been an important issue in the field of building and facility management, and its development is also one of the essential factors for achieving sustainable infrastructure.
Since the estimation of RSL of buildings is heavily affected by the subjectivity of individual inspector or engineer, much effort has been placed in the development of a rational method that can estimate the RSL of existing buildings more quantitatively using objective measurement indices. Various uncertain factors contribute to the deterioration of the structural performance of buildings, and most of the common building structures are constructed not with a single structural member but with various types of structural components (e.g., beams, slabs, and columns) in multistory floors. Most existing RSL estimation methods, however, consider only an individual factor. In this study, an estimation method for RSL of concrete buildings is presented by utilizing a fuzzy theory to consider the effects of multiple influencing factors on the deterioration of durability (e.g., concrete carbonation, chloride attack, sulfate attack), as well as the current structural condition (or damage level) of buildings.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002000534
|
oai_dc
|
Numerical simulation of hollow steel profiles for lightweight concrete sandwich panels
|
Numerical simulation of hollow steel profiles for lightweight concrete sandwich panels
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"E.Brunesi(UME school); R. Nascimbene(EUCENTRE); M.Deyanova(UME school); C.Pagani(Styl-Comp group Via Stezzano); S.Zambelli(Styl-Comp group Via Stezzano)"
] |
The focus of the present study is to investigate both local and global behaviour of a precast concrete sandwich panel. The selected prototype consists of two reinforced concrete layers coupled by a system of cold-drawn steel profiles and one intermediate layer of insulating material. High-definition nonlinear finite element (FE) models, based on 3D brick and 2D interface elements, are used to assess the capacity of this technology under shear, tension and compression. Geometrical nonlinearities are accounted via large displacement-large strain formulation, whilst material nonlinearities are included, in the series of simulations, by means of Von Mises yielding criterion for steel elements and a classical total strain crack model for concrete; a bond-slip constitutive law is additionally adopted to reproduce steel profile-concrete layer interaction. First, constitutive models are calibrated on the basis of preliminary pull and pull-out tests for steel and concrete, respectively. Geometrically and materially nonlinear FE simulations are performed, in compliance with experimental tests, to validate the proposed modeling approach and characterize shear, compressive and tensile response of this system, in terms of global capacity curves and local stress/strain distributions. Based on these experimental and numerical data, the structural performance is then quantified under various loading conditions, aimed to reproduce the behaviour of this solution during production, transport, construction and service conditions.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002104528
|
oai_dc
|
Buckling analysis of embedded concrete columns armed with carbon nanotubes
|
Buckling analysis of embedded concrete columns armed with carbon nanotubes
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ali Jafarian Arani(Islamic Azad University); Reza Kolahchi(Islamic Azad University)"
] |
As concrete is most usable material in construction industry it’s been required to improve its quality. Nowadays, nanotechnology offers the possibility of great advances in construction. For the first time, the nonlinear buckling of straight concrete columns armed with single-walled carbon nanotubes (SWCNTs) resting on foundation is investigated in the present study. The column is modelled with Euler-Bernoulli and Timoshenko beam theories. The characteristics of the equivalent composite being determined using mixture rule. The foundation around the column is simulated with spring and shear layer. Employing nonlinear strains-displacements, energy methods and Hamilton's principal, the governing equations are derived. Differential quadrature method (DQM) is used in order to obtain the buckling load of structure. The influences of volume percent of SWCNTs, geometrical parameters, elastic foundation and boundary conditions on the buckling of column are investigated. Numerical results indicate that reinforcing the concrete column with SWCNTs, the structure becomes stiffer and the buckling load increases with respect to concrete column armed with steel.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002104552
|
oai_dc
|
Evaluation of the effect of aggregate on concrete permeability using grey correlation analysis and ANN
|
Evaluation of the effect of aggregate on concrete permeability using grey correlation analysis and ANN
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Lijuan Kong(Shijiazhuang Tiedao University); Xiaoyu Chen(Shijiazhuang Tiedao University); Yuanbo Du(Shijiazhuang Tiedao University)"
] |
In this study, the influence of coarse aggregate size and type on chloride penetration of concrete was investigated, and the grey correlation analysis was applied to find the key influencing factor.
Furthermore, the proposed 6-10-1 artificial neural network (ANN) model was constructed, and performed under the MATLAB program. Training, testing and validation of the model stages were performed using 81 experiment data sets. The results show that the aggregate type has less effect on the concrete permeability, compared with the size effect. For concrete with a lower w/b, the coarse aggregate with a larger particle size should be chose, however, for concrete with a higher w/c, the aggregate with a grading of 5-20 mm is preferred, too large or too small aggregates are adverse to concrete chloride diffusivity. A new idea for the optimum selection of aggregate to prepare concrete with a low penetration is provided. Moreover, the ANN model predicted values are compared with actual test results, and the average relative error of prediction is found to be 5.62%. ANN procedure provides guidelines to select appropriate coarse aggregate for required chloride penetration of concrete and will reduce number of trial and error, save cost and time.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002104547
|
oai_dc
|
Self compacting reinforced concrete beams strengthened with natural fiber under cyclic loading
|
Self compacting reinforced concrete beams strengthened with natural fiber under cyclic loading
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Prasad M.L.V(NIT); Prasenjit saha(NIT); P.R.Kumar(National Institute of Technology)"
] |
The present work focuses on the use of coconut fiber in self compacting concrete. Self- Compacting Concrete (SCC) is a highly flowable, stable concrete which flows readily into place, filling formwork without any consolidation and without undergoing any significant segregation. Use of fibers in SCC bridge the cracks and enhance the performance of concrete by not allowing cracks to propagate. They contribute to an increased energy absorption compared to plain concrete. Coconut fiber has the highest toughness among all natural fibers. It is known that structures in the seismic prone areas are always under the influence of cyclic loading. To justify the importance of strengthening SCC beams with coir fiber, the present work has been undertaken. A comparison is made between cyclic and static loading of coconut fiber reinforced self compacting concrete (FRSCC) members. Using the test data obtained from the experiment, hysteresis loops were drawn and comparison of envelope curve, energy dissipation, stiffness degradation were made and important conclusions were draw to justify the use of coconut fiber in SCC.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002107144
|
oai_dc
|
Cost effective optimal mix proportioning of high strength self compacting concrete using response surface methodology
|
Cost effective optimal mix proportioning of high strength self compacting concrete using response surface methodology
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Asaduzzaman Khan(Kunsan National University); 도정윤(군산대학교); 김두기(군산대학교)"
] |
Optimization of the concrete mixture design is a process of search for a mixture for which the sum of the cost of the ingredients is the lowest, yet satisfying the required performance of concrete. In this study, a statistical model was carried out to model a cost effective optimal mix proportioning of high strength selfcompacting concrete (HSSCC) using the Response Surface Methodology (RSM). The effect of five key mixture parameters such as water-binder ratio, cement content, fine aggregate percentage, fly ash content and superplasticizer content on the properties and performance of HSSCC like compressive strength, passing ability, segregation resistance and manufacturing cost were investigated. To demonstrate the responses of model in quadratic manner Central Composite Design (CCD) was chosen. The statistical model showed the adjusted correlation coefficient R2adj values were 92.55%, 93.49%, 92.33%, and 100% for each performance which establish the adequacy of the model. The optimum combination was determined to be 439.4 kg/m3 cement content, 35.5% W/B ratio, 50.0% fine aggregate, 49.85 kg/m3 fly ash, and 7.76 kg/m3 superplasticizer within the interest region using desirability function. Finally, it is concluded that multiobjective optimization method based on desirability function of the proposed response model offers an efficient approach regarding the HSSCC mixture optimization.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002107148
|
oai_dc
|
A study about determination of preliminary design & minimum reinforcement ratios
|
A study about determination of preliminary design & minimum reinforcement ratios
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Varol KOC(Ondokuz Mayıs University); Yusuf EMİROGLU(Ondokuz Mayıs University)"
] |
In the standards, minimum reinforcement ratios are presented as the least reinforcement ratios that bearing elements should have in a way to include all systems and in general. However, naturally these general minimum ratios might be presented as being lower than the normally required reinforcement ratios by criteria such as system size, bearing system arrangement, section situation and distributions of the elements and earthquake effect. In this case, minimum reinforcement ratios may remain as meaningless restrictions. Then grouping the criterion that might affect reinforcement ratios according to certain parameters and creating minimum reinforcement ratios regarding preliminary design will provide ease and safety during the project designing. Moreover, it will enable fast and simple examinations in the beginning of project control and evaluation process. By means of the data which could be defined as “preliminary design & minimum reinforcement ratios”, a more realistic and safe restriction compared to general minimum reinforcement ratios could be presented. As a result of numerous comprehensive studies, reinforcement ratios to include all certain systems might be obtained. Today, thanks to the development level of finite elements programs which can make reinforced concrete modelling, with the studies that are impossible to carry out beforehand, this deficiency in the minimum reinforcement ratios in the standarts may at least be partially made up with the advisory regulation of preliminary design & minimum reinforcement ratios. As the structure of the system to be examined and the diversity of the parameters range from the specific to the general, preliminary design & minimum reinforcement ratios will approximate to general minimum reinforcement ratios in real terms. By focusing on a more specific system structure and diversity of the parameters, preliminary design and even design reinforcement ratios will be approximated. In this preliminary study, a route between these two extremes was attempted to be followed. Today, it is possible to determine suggested practical ratios for project designs through carrying out numerous studies.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002104543
|
oai_dc
|
Nonlinear analysis of the RC structure by higher-order element with the refined plastic hinge
|
Nonlinear analysis of the RC structure by higher-order element with the refined plastic hinge
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"C.K. IU(Queensland University of Technology)"
] |
This paper describes a method of the refined plastic hinge approach in the framework of the higher-order element formulation that can efficaciously evaluate the limit state capacity of a whole reinforced concrete structural system using least number of element(s), whereas the traditional design of a reinforced concrete structure (i.e. AS3600; Eurocode 2) is member-based approach. Hence, in regard to the material nonlinearities, the efficient and economical cross-section analysis is provided to evaluate the element section capacity of non-uniform and arbitrary concrete section subjected to the interaction effects, which is helpful to formulate the refined plastic hinge method. In regard to the geometric nonlinearities, this paper relies on the higher-order element formulation with element load effect. Eventually, the load redistribution can be considered and make full use of the strength reserved owing to the redundancy of an indeterminate structure. And it is particularly true for the performance-based design of a structure under the extreme loads, while the uncertainty of the extreme load is great that the true behaviour of a whole structural system is important for the economical design approach, which is great superiority over the conservative optimal strength of an individual and isolated member based on traditional design (i.e. AS3600; Eurocode 2).
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002107146
|
oai_dc
|
Experimental study of shear behavior of planar nonpersistent joint
|
Experimental study of shear behavior of planar nonpersistent joint
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hadi Haeri(Islamic Azad University); Vahab Sarfarazi(Hamedan University of Technology); Hossein Ali Lazemi(Islamic Azad University)"
] |
The present article discusses the effect of the ratio of bridge surface to total shear surface, number of bridge areas and normal stress on the failure behavior of the planar non-persistent open joints. Totally, 38 models were prepared using plaster and dimensions of 15 cm×15 cm×15 cm. The bridge area occupied 45 cm2, 90 cm2 and 135 cm2 out of the shear surface. The number of rock bridges increase in fixed area. Two similar samples were prepared on every variation in the rock bridges and tested for direct shear strength under two high and low normal loads. The results indicated that the failure pattern and the failure mechanism is mostly influenced by the ratio of bridge surface to total shear surface and normal stress so that the tensile failure mode change to shear failure mode by increasing in the value of introduced parameters.
Furthermore, the shear strength and shear stiffness are closely related to the ratio of bridge surface to total shear surface, number of bridge areas and normal stress.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002107147
|
oai_dc
|
Prediction of chloride binding isotherms for blended cements
|
Prediction of chloride binding isotherms for blended cements
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hailong Ye(Zhejiang University); Xianyu Jin(Zhejiang University); Wei Chen(Zhejiang University); Chuanqing Fu(Zhejiang University); Nanguo Jin(Zhejiang University)"
] |
A predictive model for chloride binding isotherms of blended cements with various supplementary cementitious materials (SCMs) was established in this work. Totally 560 data points regarding the chloride binding isotherms of 106 various cements were collected from literature. The total amount of bound chloride for each mixture was expressed a combinational function of the predicted phase assemblage and binding isotherms of various hydrated phases. New quantitative expressions regarding the chloride binding isotherms of calcium-silicate-hydrate (C-S-H), AFm, and hydrotalcite phases were provided. New insights about the roles of SCMs on binding capabilities of ordinary portland cements (OPC) were discussed. The proposed model was verified using separate data from different sources and was shown to be reasonably accurate.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001905298
|
oai_dc
|
Statistical division of compressive strength results on the aspect of concrete family concept
|
Statistical division of compressive strength results on the aspect of concrete family concept
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Józef Jasiczak(Poznan University of Technology); Marcin Kanoniczak(Poznan University of Technology); Łukasz Smaga(Science Adam Mickiewicz University)"
] |
The article presents the statistical method of grouping the results of the compressive strength of concrete in continuous production. It describes the method of dividing the series of compressive strength results into batches of statistically stable strength parameters at specific time intervals, based on the standardized concept of “concrete family”. The article presents the examples of calculations made for two series of concrete strength results, from which sets of decreased strength parameters were separated. When assessing the quality of concrete elements and concrete road surfaces, the principal issue is the control of the compressive strength parameters of concrete. Large quantities of concrete mix manufactured in a continuous way should be subject to continuous control. Standardized approach to assessing the concrete strength proves to be insufficient because it does not allow for the detection of subsets of the decreased strength results, which in turn makes it impossible to make adjustments to the concrete manufacturing process and to identify particular product or area on site with decreased concrete strength. In this article two independent methods of grouping the test results of concrete with statistically stable strength parameters were proposed, involving verification of statistical hypothesis based on statistical tests: Student’s t-test and Mann – Whitney – U test.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001905295
|
oai_dc
|
Mechanical analysis for prestressed concrete containment vessels under loss of coolant accident
|
Mechanical analysis for prestressed concrete containment vessels under loss of coolant accident
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Zhen Zhou(Southeast University); Chang Wu(Southeast University); Shao-ping Meng(Southeast University); Jing Wu(Southeast University)"
] |
LOCA (Loss Of Coolant Accident) is one of the most important utmost accidents for Prestressed Concrete Containment Vessel (PCCV) due to its coupled effect of high temperature and inner pressure. In this paper, heat conduction analysis is used to obtain the LOCA temperature distribution of PCCV. Then the elastic internal force of PCCV under LOCA temperature is analyzed by using both simplified theoretical method and FEM (finite element methods) method. Considering the coupled effect of LOCA temperature, a nonlinear elasto-plasitic analysis is conducted for PCCV under utmost internal pressure considering three failure criteria. Results show that the LOCA temperature distribution is strongly nonlinear along the shell thickness at the early time; the moment result of simplified analysis is well coincident with the one of numerical analysis at weak constraint area; while in the strong constrained area, the value of moments and membrane forces fluctuate dramatically; the simplified and numerical analysis both show that the maximum moment occurs at 6hrs after LOCA.; the strain of PCCV under LOCA temperature is larger than the one of no temperature under elasto-plastic analysis; the LOCA temperature of 6hrs has the greatest influence on the ultimate bearing capacity with 8.43% decrease for failure criteria 1 and 2.65% decrease for failure criteria 3.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001905310
|
oai_dc
|
Computer based estimation of backbone curves for hysteretic Response of reinforced concrete columns under static cyclic lateral loads
|
Computer based estimation of backbone curves for hysteretic Response of reinforced concrete columns under static cyclic lateral loads
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"M. Rizwan(University of Witwatersrand); M.T.A. Chaudhary(Al Imam Mohammad Ibn Saud Islamic University); M. Ilyas(University of Engineering & Technology); Raja Rizwan Hussain(King Saud University); T.R. Stacey(University of Witwatersrand)"
] |
Cyclic test of the columns is of practical relevance to the performance of compression members during an earthquake loading. The strength, ductility and energy absorption capabilities of reinforced concrete (RC) columns subjected to cyclic loading have been estimated by many researchers. These characteristics are not normally inherent in plain concrete but can be achieved by effectively confining columns through transverse reinforcement. An extensive experimental program, in which performance of four RC columns detailed according to provisions of ACI-318-08 was studied in contrast with that of four columns confined by a new proposed technique. This paper presents performance of columns reinforced by standard detailing and cast with 25 and 32 MPa concrete. The experimentally achieved load-displacement hysteresis and backbone curves of two columns are presented. The two approaches which work in conjunction with Response 2000 have been suggested to draw analytical back bone curves of RC columns. The experimental and analytical backbone curves are found in good agreement. This investigation gives a detail insight of the response of RC columns subjected to cyclic loads during their service life. The suggested analytical procedures will be available to the engineers involved in design to appraise the capacity of RC columns.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001905273
|
oai_dc
|
Force transfer mechanism in positive moment continuity details for prestressed concrete girder bridges
|
Force transfer mechanism in positive moment continuity details for prestressed concrete girder bridges
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Tanvir Hossain(SBM Offshore); Ayman M. Okeil(Louisiana State University)"
] |
The force transfer mechanism in positive moment continuity details for prestressed concrete girder bridges is investigated in this paper using a three-dimensional detailed finite element model. Positive moment reinforcement in the form of hairpin bars as recommended by the National Cooperative Highway Research Program Report No 519 is incorporated in the model. The cold construction joint that develops at the interface between girder ends and continuity diaphragms is also simulated via contact elements. The model is then subjected to the positive moment and corresponding shear forces that would develop over theservice life of the bridge. The stress distribution in the continuity diaphragm and the axial force distribution in the hairpin bars are presented. It was found that due to the asymmetric configuration of the hairpin bars, asymmetric stress distribution develops at the continuity diaphragm, which can be exacerbated by other asymmetric factors such as skewed bridge configurations. It was also observed that when the joint is subjected to a positive moment, the tensile force is transferred from the girder end to the continuity diaphragm only through the hairpin bars due to the lack of contact between the both members at the construction joint. As a result, the stress distribution at girder ends was found to be concentrated around thehairpin bars influence area, rather than be resisted by the entire girder composite section. Finally, the results are used to develop an approach for estimating the cracking moment capacity at girder ends based on a proposed effective moment of inertia.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001905301
|
oai_dc
|
Damping determination of FRP-confined reinforced concrete columns
|
Damping determination of FRP-confined reinforced concrete columns
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yuan-Feng Wang(Beijing Jiaotong University); Xiaoran Li(Beijing Jiaotong University); Li Su(Beijing Jiaotong University)"
] |
Damping as a material property plays an important role in decreasing dynamic response of structures. However, very little is known about the evaluation and application of the actual damping of Fiber Reinforced Polymer Confined Reinforced Concrete (FRP-C RC) material which is widely adopted in civil engineering at present. This paper first proposes a stress-dependent damping model for FRP-C RC material using a validated Finite Element Model (FEM), then based on this damping-stress relation, an iterative scheme is developed for the computations of the non-linear damping and dynamic response of FRP-C RC columns at any given harmonic exciting frequency. Numerical results show that at resonance, a considerable increase of the loss factor of the FRP-C RC columns effectively reduces the dynamic response of the columns, and the columns with lower concrete strength, FRP volume ratio and axial compression ratio or higher longitudinal reinforcement ratio have stronger damping values, and can relatively reduce the resonant response.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001905304
|
oai_dc
|
Mechanical properties and durability of self consolidating cementitious materials incorporating nano silica and silica fume
|
Mechanical properties and durability of self consolidating cementitious materials incorporating nano silica and silica fume
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ali Akbar Ramezanianpour(Amirkabir University of Technology); Mahdi Mahdikhani(Amirkabir University of Technology)"
] |
In recent years, the emergence of nanotechnology and nanomaterial has created hopes to improve various properties of concrete. Nano silica as one of these materials has been introduced as a cement replacement material for concrete mixture in construction applications. It can modify the properties of concrete, due to high pozzolanic reactions and also making a denser microstructure. On the other hand, it is well recognized that the use of mineral admixtures such as silica fume affects the mechanical properties and durability of cementitious materials. In addition, the superior performance of self-consolidating concrete (SCC) and self-consolidating mortars (SCM) over conventional concrete is generally related to their ingredients. This study investigates the effect of nano silica and silica fume on the compressive strength and chloride permeability of self-consolidating mortars. Tests include compressive strength, rapid chloride permeability test, water permeability, capillary water absorption, and surface electrical resistance, which carried out on twenty mortar mixtures containing zero to 6 percent of nano silica and silica fume. Results show that SCMs incorporating nano silica had higher compressive strength at various ages. In addition, results show that nano silica has enhanced the durability SCMs and reduced the chloride permeability.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002133634
|
oai_dc
|
Numerical analysis of the thermal behaviors of cellular concrete
|
Numerical analysis of the thermal behaviors of cellular concrete
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Wei She(Southeast University); Guotang Zha(China Railway Corporation); Guotao Yang(China Railway Corporation); Jinyang Jiang(Southeast University); Xiaoyu Cao(Southeast University); Yi Du(Southeast University)"
] |
In this study, both two- and three-dimensional (2D and 3D) finite-volume-based models were developed to analyze the heat transfer mechanisms through the porous structures of cellular concretes under steady-state heat transfer conditions and to investigate the differences between the 2D and 3D modeling results. The 2D and 3D reconstructed pore networks were generated from the microstructural information measured by 3D images captured by X-ray computerized tomography (X-CT). The computed effective thermal conductivities based on the 2D and 3D calculations performed on the reconstructed porous structures were found to be nearly identical to those evaluated from the 2D cross-sectional images and the 3D X-CT images, respectively. In addition, the 3D computed effective thermal conductivity was found to agree better with the measured values, in comparison with the 2D reconstruction and real cross-sectional images. Finally, the thermal conductivities computed for different reconstructed porous 3D structures of cellular concretes were compared with those obtained from 2D computations performed on 2D reconstructed structures. This comparison revealed the differences between 2D and 3D image-based modeling. A correlation was thus derived between the results of the 3D and 2D models.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002133638
|
oai_dc
|
Behavior of reinforced concrete plates under impact loading: different support conditions and sizes
|
Behavior of reinforced concrete plates under impact loading: different support conditions and sizes
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Metin Husem(Karadeniz Technical University); Suleyman I. Cosgun(Karadeniz Technical University)"
] |
In this study, effects of impact loads on reinforced concrete (RC) plates are examined analytically. During examination of RC plates, they were exposed to impact loading with two different support conditions in three different sizes. RC plates in different support conditions were analyzed with Concrete Damage Plasticity Model (CDP) and reinforcing steel was modeled with Classical Metal Plasticity Model (CMP) by ABAQUS finite element software. After the analysis it is found that impact loads, displacements, energy absorption capacities and damage patterns are changed due to support conditions and plate sizes. Results that are obtained from RC plate experiments in literature under impact loads are found to be similar with the results of numerical analysis with CDP material models.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002133637
|
oai_dc
|
A simple practical method for determination of moisture transfer coefficient of mature concrete using a combined experimental-numerical approach
|
A simple practical method for determination of moisture transfer coefficient of mature concrete using a combined experimental-numerical approach
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mehdi Nemati Chari(University of Tehran); Mohammad Shekarchi(University of Tehran); Pouria Ghods(Giatec Scientific Inc); Masoud Moradian(Oklahoma State University)"
] |
In this paper, a simple practical method is introduced in which a simple weight measurement of concrete and finite element numerical analysis are used to determine the moisture transfer coefficient of concrete with a satisfactory accuracy. Six concrete mixtures with different water-to-cementitious material (w/cm) ratios and two pozzolanic materials including silica fume and zeolite were examined to validate the proposed method. The comparison between the distribution of the moisture content obtained from the model and the one from the experimental data during both the wetting and drying process properly validated the performance of the method.With the proposed method, it was also shown that the concrete moisture transfer coefficient considerably depends on the pore water saturation degree. The use of pozzolanic materials and also lowering w/cm ratio increased the moisture transfer coefficient during the initial sorption, and then, it significantly decreased with an increase in the water saturation degree.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002133639
|
oai_dc
|
Remote sensing and photogrammetry techniques in diagnostics of concrete structures
|
Remote sensing and photogrammetry techniques in diagnostics of concrete structures
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Artur Janowski(Gdansk University of Technology); Krystyna Nagrodzka-Godycka(Gdansk University of Technology); Jakub Szulwic(Gdansk University of Technology); Patryk Ziółkowski(Gdansk University of Technology)"
] |
Recently laser scanning technologies become widely used in many areas of the modern economy.
In the following paper authors show a potential spectrum of use Terrestrial Laser Scanning (TLS) in diagnostics of reinforced concrete elements. Based on modes of failure analysis of reinforcement concrete beam authors describe downsides and advantages of adaptation of terrestrial laser scanning to this purpose, moreover reveal under which condition this technology might be used. Research studies were conducted by Faculty of Civil and Environmental Engineering at Gdansk University of Technology. An experiment involved bending of reinforced concrete beam, the process was registered by the terrestrial laser scanner.
Reinforced concrete beam was deliberately overloaded and eventually failed by shear.Whole failure process was tracing and recording by scanner Leica ScanStation C10 and verified by synchronous photographic registration supported by digital photogrammetry methods. Obtained data were post-processed in Leica Cyclone (dedicated software) and MeshLab (program on GPL license). The main goal of this paper is to prove the effectiveness of TLS in diagnostics of reinforced concrete elements. Authors propose few methods and procedures to virtually reconstruct failure process, measure geometry and assess a condition of structure.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002133640
|
oai_dc
|
Experimental and numerical analysis of corrosion-induced cover cracking in reinforced concrete sample
|
Experimental and numerical analysis of corrosion-induced cover cracking in reinforced concrete sample
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Benjamin Richard(Laboratoire d'Etudes Mécaniques et Sismiques); Marc Quiertant(Universite Paris-Est); Veronique Bouteiller(Universite Paris-Est); Arnaud Delaplace(Lafarge Centre de Recherche - Mecanique et Modes Constructifs); Lucas Adelaide(Universite Paris-Est); Frederic Ragueneau(Univ. Paris); Christian Cremona(Bouygues Construction)"
] |
Corrosion of embedded reinforcing bars is recognized as being the major cause of deterioration of reinforced concrete structures. With regard to maintenance strategies of concrete nuclear structures, the monitoring of cracking remains of primary importance. Recently, authors have developed a post-treatment technique to extract crack features from continuous computations. In this paper, such technique is applied to carry out a numerical analysis of an accelerated corrosion test. Obtained results allow highlighting specific propagation and failure mechanisms that characterize corrosion-induced cracking.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002133636
|
oai_dc
|
Tests of concrete slabs reinforced with CFRP prestressed prisms
|
Tests of concrete slabs reinforced with CFRP prestressed prisms
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jiongfeng Liang(Fundamental Science on Radioactive Geology and Exploration Technology Laboratory); Deng Yu(Guangxi University of Science and Technology); Ze-Ping Yang(East China Institute of Technology); Xinjun Chai(East China Institute of Technology)"
] |
This paper reports the testing of concrete slabs reinforced with CFRP prestressed concrete prisms(PCP) on the flexural behavior. Four concrete slabs were tested, a reference slab reinforced with steel bars, and three slabs reinforced with CFRP prestressed concrete prisms (PCP). All slabs were made with dimensions of 600mm in width, 2200mm in length and 150 in depth. All concrete slabs reinforced with CFRP prestressed concrete prisms(PCP) exhibited CFRP bar rupture failure mode. It was shown that the application of the CFRP prestressed prisms can limit service load deflections and crack width, the increased level of prestress in the CFRP prestressed prism positively affected the maximum crack width. The deflection of concrete slabs reinforced with CFRP prestressed prisms decreased as prestress in the CFRP prestressed prism increased.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002133633
|
oai_dc
|
Stud reinforcement in beam-column joints under seismic loads
|
Stud reinforcement in beam-column joints under seismic loads
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Gholamreza Abdollahzadeh(Babol University of Technology); Saeed Eilbeigi Ghalani(Shomal University)"
] |
Current codes recommend large amounts of shear reinforcement for reinforced concrete beamcolumn joints that causes significant bar congestion. Increase in congestion of shear reinforcement in joint core (connection zone), leads to increase accomplishment problems. The congestion may also lead to diameter limitations on the beam bars relative to the joint dimensions. Using double headed studs instead of conventional closed hoops in reinforced concrete beam-column joints reduces congestion and ensures easier assembly of the reinforcing cage. The purpose of this research is evaluating the efficiency of the proposed reinforcement. In this way, 10 groups of exterior beam-column joints are modeled. Each group includes 7 specimens by different reinforcing details in their joint core. All specimens are modeled by using of ABAQUS and analyzed subjected to cyclic loading. After verification of analytical modeling with an experimental specimen, 3D nonlinear specimens are modeled and analyzed. Then, the effect of amount and arrangement of headed studs on ductility, performance, ultimate strength and energy absorption has been studied. Based on the results, all joints reinforced with double headed studs represent better performance compared with the joints without shear transverse reinforcement in joints core. The behavior of the former is close to joints reinforced with closed hoops and cross ties according to the seismic design codes. By adjusting the arrangement of double-headed studs, the decrease in ductility, performance, ultimate moment resistant and energy absorption reduce to 2.61%, 0.90%, 0.90% and 1.66% respectively compared with the joints reinforced by closed hoops on the average. Since the use of headed studs reduces accomplishment problems, these amounts are negligible. Therefore, use of double-headed studs has proved to be a viable option for reinforcing exterior beam-column joints.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002133635
|
oai_dc
|
Study on fracture characteristics of reinforced concrete wedge splitting tests
|
Study on fracture characteristics of reinforced concrete wedge splitting tests
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hu Shaowei(Nanjing Hydraulic Research Institute); XU Aiqing(Hohai University); HU Xin(Nanjing Hydraulic Research Institute); YIN Yangyang(Hohai University)"
] |
To study the influence on fracture properties of reinforced concrete wedge splitting test specimens by the addition of reinforcement, and the restriction of steel bars on crack propagation, 7 groups reinforced concrete specimens of different reinforcement position and 1 group plain concrete specimens with the same size factors were designed and constructed for the tests. Based on the double-K fracture criterion and tests, fracture toughness calculation model which was suitable for reinforced concrete wedge splitting tensile specimens has been obtained. The results show that: the value of initial craking load Pini and unstable fracture load Pun decreases gradually with the distance of reinforcement away from specimens’s top. Compared with plain concrete specimens, addition of steel bar can reduce the value of initial fracture toughness KIini, but significantly increase the value of the critical effective crack length ac and unstable fracture toughness KIun. For tensional concrete member, the effect of anti-cracking by reinforcement was mainly acted after cracking, the best function of preventing fracture initiation was when the steel bar was placed in the middle of the crack, and when the reinforcement was across the crack and located away from crack tip, it plays the best role in inhibiting the extension of crack.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001793910
|
oai_dc
|
Elasto-plastic time history analysis of an asymmetrical twin-tower rigid-connected structure
|
Elasto-plastic time history analysis of an asymmetrical twin-tower rigid-connected structure
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Xiaohan Wu(Tongji University); Yanfei Sun(Tongji University); Mingzhuo Rui(East China Architectural Design & Resea); Min Yan(East China Architectural Design & Resea); Lishu Li(East China Architectural Design & Resea); Dongze Liu(Tongji University)"
] |
The structure analyzed in this paper has particular building style and special structural system. It is a rigid-connected twin-tower skyscraper with asymmetrical distribution of stiffness and masses in two towers. Because of the different stiffness between the north and the south towers, the torsion seismic vibration is significant. In this paper, in order to study the seismic response of the structure under both frequent low-intensity earthquakes as well as rare earthquakes at the levels of intensity 7, the analysis model is built and analyzed with NosaCAD. NosaCAD is an nonlinear structure analysis software based on second-development of AutoCAD with ObjectARX. It has convenient modeling function, high computational efficiency and diversity post-processing functions. The deformations, forces and damages of the structure are investigated based on the analysis. According to the analysis, there is no damage on the structure under frequent earthquakes, and the structure has sufficient capacity and ductility to resist rare earthquakes. Therefore the structure can reach the goal of no damage under frequent earthquakes and no collapse under rare earthquakes. The deformation of the structure is below the limit in Chinese code. The time sequence and distribution of damages on tubes are reasonable, which can dissipate some dynamic energy. At last, according to forces, load-carrying capacity and damage of elements, there are some suggestions on increasing the reinforcement in the core tube at base and in stiffened stories.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001793902
|
oai_dc
|
Seismic performances of RC columns reinforced with screw ribbed reinforcements connected by mechanical splice
|
Seismic performances of RC columns reinforced with screw ribbed reinforcements connected by mechanical splice
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"이세정((주)세진구조안전기술사사무); 이득행(서울시립대학교); 김강수(서울시립대학교); 오재열(서울시립대학교); 박민국(서울시립대학교); 양일승(동신대학교)"
] |
Various types of reinforcement splicing methods have been developed and implemented in reinforced concrete construction projects for achieving the continuity of reinforcements. Due to the complicated reinforcement arrangements and the difficulties in securing bar spacing, the traditional lap splicing method, which has been widely used in reinforced concrete constructions, often shows low constructability and difficulties in quality control. Also, lap spliced regions are likely to be over-reinforced, which may not be desirable in seismic design. On the other hand, mechanical splicing methods can offer simple and clear arrangements of reinforcement. In order to utilize the couplers for the ribbed-deformed bars, however, additional screw processing at the ends of reinforcing bars is typically required, which often lead to performance degradations of reinforced concrete members due to the lack of workmanship in screw processing or in adjusting the length of reinforcing bars. On the contrary, the use of screw-ribbed reinforcements can easily solve these issues on the mechanical splicing methods, because it does not require the screw process on the bar. In this study, the mechanical coupler suitable for the screw-ribbed reinforcements has been developed, in which any gap between the reinforcements and sleeve device can be removed by grouting high-flow inorganic mortar. This study presents the uniaxial tension tests on the screw-ribbed reinforcement with the mechanical sleeve devices and the cyclic loading tests on RC columns with the developed coupler. The test results show that the mechanical sleeve connection developed in this study has an excellent splicing performance,and that it is applicable to reinforced concrete columns with a proper confinement by hoop reinforcement.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001793904
|
oai_dc
|
Prediction of lightweight concrete strength by categorized regression, MLR and ANN
|
S. Tavakkol1,2, F. Alapour2, A. Kazemian2, A. Hasaninejad3, A. Ghanbari4, A. A. Ramezanianpour5
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S. Tavakkol(Water Research Institute); F. Alapour(Amirkabir University of Technology); A. Kazemian(Amirkabir University of Technology); A. Hasaninejad(Shahed University); A. Ghanbari(Amirkabir University of Technology); A.A. Ramezanianpour(Amirkabir University of Technology)"
] |
Prediction of concrete properties is an important issue for structural engineers and different methods are developed for this purpose. Most of these methods are based on experimental data and use measured data for parameter estimation. Three typical methods of output estimation are Categorized Linear Regression (CLR), Multiple Linear Regression (MLR) and Artificial Neural Networks (ANN). In this paper a statistical cleansing method based on CLR is introduced. Afterwards, MLR and ANN approaches are also employed to predict the compressive strength of structural lightweight aggregate concrete. The valid input domain is briefly discussed. Finally the results of three prediction methods are compared to determine the most efficient method. The results indicate that despite higher accuracy of ANN, there are some limitations for the method. These limitations include high sensitivity of method to its valid input domain and selection criteria for determining the most efficient network.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001793908
|
oai_dc
|
Prediction of the transfer length of prestressing strands with neural networks
|
Prediction of the transfer length of prestressing strands with neural networks
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"José R. Martí-Vargas(Universitat Politècnica de València); Víctor Yepes(Universitat Politècnica de València); Francesc J. Ferri(Universitat de València,)"
] |
This paper presents a study on the prediction of transfer length of 13 mm seven-wire prestressing steel strand in pretensioned prestressed concrete members with rectangular cross-section including several material properties and design and manufacture parameters. To this end, a carefully selected database consisting of 207 different cases coming from 18 different sources spanning a variety of practical transfer length prediction situations was compiled. 16 single input features and 5 combined input features are analyzed. A widely used feedforward neural regression model was considered as a representative of several machine learning methods that have already been used in the engineering field. Classical multiple linear regression was also considered in order to comparatively assess performance and robustness in this context. The results show that the implemented model has good prediction and generalization capacity when it is used on large input data sets of practical interest from the engineering point of view. In particular, a neural model is proposed -using only 4 hidden units and 10 input variables- which significantly reduces in 30% and 60% the errors in transfer length prediction when using standard linear regression or fixed formulas, respectively.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001793899
|
oai_dc
|
Genetic-fuzzy approach to model concrete shrinkage
|
Genetic-fuzzy approach to model concrete shrinkage
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Wilson Ricardo Leal da Silva(Czech Technical University); Petr Štemberka(Czech Technical University)"
] |
This work presents an approach to model concrete shrinkage. The goal is to permit the concrete industry’s experts to develop independent prediction models based on a reduced number of experimental data. The proposed approach combines fuzzy logic and genetic algorithm to optimize the fuzzy decision-making, thereby reducing data collection time. Such an approach was implemented for an experimental data set related to self-compacting concrete. The obtained prediction model was compared against published experimental data (not used in model development) and well-known shrinkage prediction models. The predicted results were verified by statistical analysis, which confirmed the reliability of the developed model. Although the range of application of the developed model is limited, the genetic-fuzzy approach introduced in this work proved suitable for adjusting the prediction model once additional training data are provided. This can be highly inviting for the concrete industry’s experts, since they would be able to fine-tune their models depending on the boundary conditions of their production processes.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001793906
|
oai_dc
|
Effects of soil-structure interaction on construction stage analysis of highway bridges
|
Effects of soil-structure interaction on construction stage analysis of highway bridges
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Sevket Ates(Karadeniz Technical University); Barbaros Atmaca(Karadeniz Technical University); Erdal Yildirim(Karadeniz Technical University); Nurcan Asci Demiroz(Avrasya University)"
] |
The aim of this paper is to determine the effect of soil-structure interaction and time dependent material properties on behavior of concrete box-girder highway bridges. Two different finite element analyses, one stage and construction stage, have been carried out on Komurhan Bridge between Elazığ and Malatya province of Turkey, over Fırat River. The one stage analysis assume that structure was built in a second and material properties of structure not change under different loads and site conditions during time. However, construction stage analysis considers that construction time and time dependent material properties. The main and side spans of bridge are 135 m and 76 m, respectively. The bridge had been constructed in 3 years between 1983 and 1986 by balanced cantilever construction method. The parameters of soil-structure interaction (SSI), time dependent material properties and construction method are taken into consideration in the construction stage analysis while SSI is single parameter taking into consideration in the one stage analysis. The 3D finite element model of bridge is created the commercial program of SAP2000. Time dependent material properties are elasticity modulus, creep and shrinkage for concrete and relaxation for steel. Soft, medium, and firm soils are selected for evaluating SSI in both analyses. The results of two different finite element analyses are compared with each other. It is seen that both construction stage and SSI have a remarkable effect on the structural behavior of the bridge.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001793912
|
oai_dc
|
Neural network based model for seismic assessment of existing RC buildings
|
Naci Caglarand Zehra Sule Garip
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Naci Caglar(University of Sakarya); Zehra Sule Garip(Karabuk University)"
] |
The objective of this study is to reveal the sufficiency of neural networks (NN) as a securer, quicker, more robust and reliable method to be used in seismic assessment of existing reinforced concrete buildings. The NN based approach is applied as an alternative method to determine the seismic performance of each existing RC buildings, in terms of damage level. In the application of the NN, a multilayer perceptron (MLP) with a back-propagation (BP) algorithm is employed using a scaled conjugate gradient. NN based model wasd eveloped, trained and tested through a based MATLAB program. The database of this model was developed by using a statistical procedure called P25 method. The NN based model was also proved by verification set constituting of real existing RC buildings exposed to 2003 Bingol earthquake. It is demonstrated that the NN based approach is highly successful and can be used as an alternative method to determine the seismic performance of each existing RC buildings.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001850166
|
oai_dc
|
Experimental and numerical studies on seismic behaviour of exterior beam-column joints
|
Experimental and numerical studies on seismic behaviour of exterior beam-column joints
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"P. Asha(St. Peter’s University); R. Sundararajan(Government College of Technology)"
] |
A nonlinear finite element analysis using ANSYS is used to evaluate the seismic behavior of reinforced concrete exterior beam-column joints. The behavior of the finite element models under cyclic loading is compared with the experimental results. Two beam-column joint specimens (SH and SHD) with square hoop confinement in joint and throughout the column with detailing as per IS 13920 are studied. The specimen SHD was provided with additional diagonal bars from column to beam to relocate the plastic hinge formation from beam-column interface. The load-displacement relationship, joint shear stress and strain in beam obtained from numerical study showed good agreement with the experimental results. This investigation proves that seismic behaviour of reinforced concrete beam-column joints under reversed cyclic loading can be evaluated successfully using finite element modeling and analysis.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001850175
|
oai_dc
|
The effect of architectural form on the earthquake behavior of symmetric RC frame systems
|
The effect of architectural form on the earthquake behavior of symmetric RC frame systems
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Tugba Inan(Izmir Institute of Technology); Koray Korkmaz(University of Cukurova); Ismail H. Cagatay(University of Cukurova)"
] |
In this study, structural irregularities in plan, which has a considerable effect on earthquake behavior of buildings, have been investigated in detail based on Turkish Earthquake Code 2007. The study consists of six main parametric models and a total of 144 sub-models that are grouped based on RC structural systems such as frame, frame + rigid core, frame with shear wall, and frame with shear wall + rigid core. All models are designed to have both symmetrical plan geometry and regular rigidity distribution. Changes in the earthquake behavior of buildings were evaluated according to the number of storeys, number of axes and the configuration of structural elements. Many findings are obtained and assessed as a result of the analysis for each structural irregularity. The study shows that structural irregularities can be observed in completely symmetric buildings in terms of plan geometry and rigidity distribution.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001850168
|
oai_dc
|
Performance and modeling of high-performance steel fiber reinforced concrete under impact loads
|
Performance and modeling of high-performance steel fiber reinforced concrete under impact loads
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ramadoss Perumal(Pondicherry Engineering College)"
] |
Impact performance of high-performance concrete (HPC) and SFRC at 28-day and 56-day under the action of repeated dynamic loading was studied. Silica fume replacement at 10% and 15% by mass and crimped steel fiber (Vf = 0.5%- 1.5%) with aspect ratios of 80 and 53 were used in the concrete mixes. Results indicated that addition of fibers in HPC can effectively restrain the initiation and propagation of cracks under stress, and enhance the impact strengths and toughness of HPC. Variation of fiber aspect ratio has minor effect on improvement in impact strength. Based on the experimental data, failure resistance prediction models were developed with correlation coefficient (R) = 0.96 and the estimated absolute variation is 1.82% and on validation, the integral absolute error (IAE) determined is 10.49%. On analyzing the data collected, linear relationship for the prediction of failure resistance with R= 0.99 was obtained. IAE value of 10.26% for the model indicates better the reliability of model. Multiple linear regression model was developed to predict the ultimate failure resistance with multiple R= 0.96 and absolute variation obtained is 4.9%.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001850159
|
oai_dc
|
Chloride diffusivity of concrete: probabilistic characteristics at meso-scale
|
Chloride diffusivity of concrete: probabilistic characteristics at meso-scale
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Zichao Pan(Tongji University); Xin Ruan(Tongji University); Airong Chen(Tongji University)"
] |
This paper mainly discusses the influence of the aggregate properties including grading, shape, content and distribution on the chloride diffusion coefficient, as well as the initiation time of steel corrosion from a probabilistic point of view. Towards this goal, a simulation method of random aggregate structure (RAS) based on elliptical particles and a procedure of finite element analysis (FEA) at meso-scale are firstly developed to perform the analysis. Next, the chloride diffusion coefficient ratio between concrete and cement paste 𝐷app𝐷cp is chosen as the index to represent the effect of aggregates on the chloride diffusion process. Identification of the random distribution of this index demonstrates that it can be viewed as actually having a normal distribution. After that, the effect of aggregates on 𝐷app𝐷cp is comprehensively studied, showing that the appropriate properties of aggregates should be decided by both of the average and the deviation of 𝐷app𝐷cp . Finally, a case study is conducted to demonstrate the application of this mesoscopic method in predicting the initiation time of steel corrosion in reinforced concrete (RC) structures. The mesoscopic probabilistic method developed in this paper can not only provide more reliable evidences on the proper grading and shape of aggregates, but also play an important role in the probability-based design method.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001850158
|
oai_dc
|
Use of partial least squares analysis in concrete technology
|
Use of partial least squares analysis in concrete technology
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Bulent Tutmez(Inonu University)"
] |
Multivariate analysis is a statistical technique that investigates relationship between multiple predictor variables and response variable and it is a very commonly used statistical approach in cement and concrete industry. During model building stage, however, many predictor variables are included in the model and possible collinearity problems between these predictors are generally ignored. In this study, use of partial least squares (PLS) analysis for evaluating the relationships among the cement and concrete properties is investigated. This regression method is known to decrease the model complexity by reducing the number of predictor variables as well as to result in accurate and reliable predictions. The experimental studies showed that the method can be used in the multivariate problems of cement and concrete industry effectively.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001850163
|
oai_dc
|
Vibration based damage identification of concrete arch dams by finite element model updating
|
Vibration based damage identification of concrete arch dams by finite element model updating
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Temel Türker(Karadeniz Technical University); Alemdar Bayraktar(Karadeniz Technical University); Barış Sevim(Yıldız Technical University)"
] |
Vibration based damage detection is very popular in the civil engineering area. Especially, special structures like dams, long-span bridges and high-rise buildings, need continues monitoring in terms of mechanical properties of material, static and dynamic behavior. It has been stated in the International Commission on Large Dams that more than half of the large concrete dams were constructed more than 50 years ago and the old dams have subjected to repeating loads such as earthquake, overflow, blast, etc.,. So, some unexpected failures may occur and catastrophic damages may be taken place because of theloss of strength, stiffness and other physical properties of concrete. Therefore, these dams need repairs provided with global damage evaluation in order to preserve structural integrity. The paper aims to show the effectiveness of the model updating method for global damage detection on a laboratory arch dam model. Ambient vibration test is used in order to determine the experimental dynamic characteristics. The initial finite element model is updated according to the experimentally determined natural frequencies and mode shapes. The web thickness is selected as updating parameter in the damage evaluation. It is observed from the study that the damage case is revealed with high accuracy and a good match is attained between the estimated and the real damage cases by model updating method.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001850156
|
oai_dc
|
Temperature effect on multi-ionic species diffusion in saturated concrete
|
Temperature effect on multi-ionic species diffusion in saturated concrete
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Nattapong Damrongwiriyanupap(University of Phayao); Linyuan Li(University of New Hampshire); Suchart Limkatanyu(Prince of Songkla University); Yunping Xi(University of Colorado at Boulder)"
] |
This study presents the mathematical model for predicting chloride penetration into saturated concrete under non-isothermal condition. The model considers not only diffusion mechanism but also migration process of chloride ions and other chemical species in concrete pore solution such as sodium, potassium, and hydroxyl ions. The coupled multi-ionic transport in concrete is described by the Nernst-Planck equation associated with electro-neutrality condition. The coupling parameter taken into account the effect of temperature on ion diffusion obtained from available test data is proposed and explicitly incorporated in the governing equations. The coupled transport equations are solved using the finite element method. The numerical results are validated with available experimental data and the comparison shows a good agreement.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001850167
|
oai_dc
|
Design procedure for prestressed concrete beams
|
Design procedure for prestressed concrete beams
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Piero Colajanni(Università di Messina); Antonino Recupero(Università di Messina); Nino Spinella(Università di Messina)"
] |
The theoretical basis and the main results of a design procedure, which attempts to provide the optimal layout of ordinary reinforcement in prestressed concrete beams, subjected to bending moment and shear force are presented. The difficulties encountered in simulating the actual behaviour of prestressed concrete beam in presence of coupled forces bending moment - shear force are discussed; particular emphasis is put on plastic models and stress fields approaches. A unified model for reinforced and prestressed concrete beams under axial force - bending moment - shear force interaction is provided. This analytical model is validated against both experimental results collected in literature and nonlinear numerical analyses. Finally, for illustrating the applicability of the proposed procedure, an example of design for a full-scale prestressed concrete beam is shown.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001850181
|
oai_dc
|
Finite element analysis of reinforced concrete spandrel beams under combined loading
|
Finite element analysis of reinforced concrete spandrel beams under combined loading
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"O.F. Ibraheem(University Sains Malaysia (USM)); B.H. Abu Bakar(University Sains Malaysia (USM)); I. Joharib(University Sains Malaysia (USM))"
] |
A nonlinear, three-dimensional finite element analysis was conducted on six intermediate L-shaped spandrel beams using the “ANSYS Civil FEM” program. The beams were constructed and tested in the laboratory under eccentric concentrated load at mid-span to obtain a combined loading case: torsion, bending, and shear. The reinforcement case parameters were as follows: without reinforcement, with longitudinal reinforcement only, and reinforced with steel bars and stirrups. All beams were tested under two different combined loading conditions: T/V = 545 mm (high eccentricity) and T/V = 145 mm (low eccentricity). The failure of the plain beams was brittle, and the addition of longitudinal steel bars increased beam strength, particularly under low eccentricity. Transverse reinforcement significantly affected the strength at high eccentricities, that is, at high torque. A program can predict accurately the behavior of these beams under different reinforcement cases, as well as under different ratios of combined loadings. The ANSYS model accurately predicted the loads and deflections for various types of reinforcements in spandrel beams, and captured the critical crack regions of these beams.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001828356
|
oai_dc
|
Predicting strength development of RMSM using ultrasonic pulse velocity and artificial neural network
|
Predicting strength development of RMSM using ultrasonic pulse velocity and artificial neural network
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hien D. Le(National Kaohsiung University of Applied); Jeng L. Huang(National Kaohsiung University of Applied); Hien D. Le(National Kaohsiung University of Applied)"
] |
Ready-mixed soil material, known as a kind of controlled low-strength material, is a new way of soil cement combination. It can be used as backfill materials. In this paper, artificial neural network and non-linear regression approach were applied to predict the compressive strength of ready-mixed soil material containing Portland cement, slag, sand, and soil in mixture. The data used for analyzing were obtained from our testing program. In the experiment, we carried out a mix design with three proportions of sand to soil (e.g., 6:4, 5:5, and 4:6). In addition, blast furnace slag partially replaced cement to improve workability, whereas the water-to-binder ratio was fixed. Testing was conducted on samples to estimate its engineering properties as per ASTM such as flowability, strength, and pulse velocity. Based on testing data, the empirical pulse velocity–strength correlation was established by regression method. Next, three topologies of neural network were developed to predict the strength, namely ANN-I, ANN-II, and ANN-III. The first two models are back-propagation feed-forward networks, and the other one is radial basis neural network. The results show that the compressive strength of ready-mixed soil material can be well-predicted from neural networks. Among all currently proposed neural network models, the ANN-I gives the best prediction because it is closest to the actual strength. Moreover, considering combination of pulse velocity and other factors, viz. curing time, and material contents in mixture, the proposed neural networks offer better evaluation than interpolated from pulse velocity only.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001828351
|
oai_dc
|
Sustainable concrete mix design for a target strength and service life
|
Sustainable concrete mix design for a target strength and service life
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Julia G. Tapali(University of Patras); Sotiris Demis(University of Patras); Vagelis G. Papadakis(University of Patras)"
] |
Considering the well known environmental issues of cement manufacturing (direct and indirect levels of CO2 emissions), clinker replacement by supplementary cementing materials (SCM) can be a very promising first step in reducing considerably the associated emissions. However, such a reduction is possible up to a particular level of SCM utilization, influenced by the rate of its pozzolanic reaction. In this study a (4-step) structured methodology is proposed in order to be able to further adjust the concrete mix design of a particular SCM, in achieving additional reduction of the associated levels of CO2 emissions and being at the same time accepted from a derived concrete strength and service life point of view. On this note, the aim of this study is twofold. To evaluate the environmental contribution of each concrete component and to provide the best possible mix design configuration, balanced between the principles of sustainability (low environmental cost) and durability (accepted concrete strength and service life ). It is shown that such a balance can be achieved, by utilising SCM by-products in the concrete mix, reducing in this way the fixed environmental emissions without compromising the long-term safety and durability of the structure.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001828359
|
oai_dc
|
Analytical and experimental modal analyses of a highway bridge model
|
Analytical and experimental modal analyses of a highway bridge model
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ahmet Can Altunișik(Karadeniz Technical University); Alemdar Bayraktar(Karadeniz Technical University); Barış Sevim(Yıldız Technical University)"
] |
In this study, analytical and experimental modal analyses of a scaled bridge model are carried out to extract the dynamic characteristics such as natural frequency, mode shapes and damping ratios. For this purpose, a scaled bridge model is constructed in laboratory conditions. Three dimensional finite element model of the bridge is constituted and dynamic characteristics are determined, analytically. To identify the dynamic characteristics experimentally; Experimental Modal Analyses (ambient and forced vibration tests) are conducted to the bridge model. In the ambient vibration tests, natural excitations are provided and the response of the bridge model is measured. Sensitivity accelerometers are placed to collect signals from the measurements. The signals collected from the tests are processed by Operational Modal Analysis; and the dynamic characteristics of the bridge model are estimated using Enhanced Frequency Domain Decomposition and Stochastic Subspace Identification methods. In the forced vibration tests, excitation of the bridge model is induced by an impact hammer and the frequency response functions are obtained. From the finite element analyses, a total of 8 natural frequencies are attained between 28.33 and 313.5 Hz. Considering the first eight mode shapes, these modes can be classified into longitudinal, transverse and vertical modes. It is seen that the dynamic characteristics obtained from the ambient and forced vibration tests are close to each other. It can be stated that the both of Enhanced Frequency Domain Decomposition and Stochastic Subspace Identification methods are very useful to identify the dynamic characteristics of the bridge model. The first eight natural frequencies are obtained from experimental measurements between 25.00-299.5 Hz. In addition, the dynamic characteristics obtained from the finite element analyses have a good correlation with experimental frequencies and mode shapes. The MAC values obtained between 90-100% and 80-100% using experimental results and experimental-analytical results, respectively.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001828355
|
oai_dc
|
Repairable k-out-n system work model analysis from time response
|
Repairable k-out-n system work model analysis from time response
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yongfeng Fang(Bijie University); Webliang Tao(Bijie University); Kong Fah Tee(University of Greenwich)"
] |
A novel reliability-based work model of k/n (G) system has been developed. Unit failure probability is given based on the load and strength distributions and according to the stress-strength interference theory. Then a dynamic reliability prediction model of repairable k/n (G) system is established using probabilistic differential equations. The resulting differential equations are solved and the value of k can be determined precisely. The number of work unit k in repairable k/n (G) system is obtained precisely.
The reliability of whole life cycle of repairable k/n (G) system can be predicted and guaranteed in the design period. Finally, it is illustrated that the proposed model is feasible and gives reasonable prediction.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001828366
|
oai_dc
|
Predictions of curvature ductility factor of doubly reinforced concrete beams with high strength materials
|
Predictions of curvature ductility factor of doubly reinforced concrete beams with high strength materials
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"이형준(한밭대학교)"
] |
The high strength materials have been more widely used in reinforced concrete structures because of the benefits of the mechanical and durable properties. Generally, it is known that the ductility decreases with an increase in the strength of the materials. In the design of a reinforced concrete beam, both the flexural strength and ductility need to be considered. Especially, when a reinforced concrete structure may be subjected an earthquake, the members need to have a sufficient ductility. So, each design code has specified to provide a consistent level of minimum flexural ductility in seismic design of concrete structures. Therefore, it is necessary to assess accurately the ductility of the beam sections with high strength materials in order to ensure the ductility requirement in design. In this study, the effects of concrete strength, yield strength of reinforcement steel and amount of reinforcement including compression reinforcement on the complete moment-curvature behavior and the curvature ductility factor of doubly reinforcement concrete beam sections have been evaluated and a newly prediction formula for curvature ductility factor of doubly RC beam sections has been developed considering the stress of compression reinforcement at ultimate state. Based on the numerical analysis results, the proposed predictions for the curvature ductility factor are verified by comparisons with other prediction formulas. The proposed formula offers fairly accurate and consistent predictions for curvature ductility factor of doubly reinforced concrete beam sections.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001828363
|
oai_dc
|
Load capacity of high-strength reinforced concrete slabs by yield line theory
|
Load capacity of high-strength reinforced concrete slabs by yield line theory
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Selçuk Emre Gӧrkem(Erciyes University); Metin Hϋsem(Karadeniz Technical University)"
] |
The objective of this study is to determine whether or not the yield line theory, an effective method widely used for slabs made of ordinary concrete, can be used also for the reinforced concrete slabs made of high-strength concrete. Flexural behavior of simply supported slabs in three different sizes were investigated under concentrated load at mid-span. Additionally, behavior of high strength reinforced concrete slabs with 50 mm and 150 mm reinforcement spacings also studied. Failure loads, deflections, experimental and theoretical failure mechanisms were evaluated. The difference between the moments based on yield line theory and experimental moments varied between 1% to 3%. Experimental and analysis results revealed that yield line analysis could conveniently be employed in the analysis of high strength reinforced concrete slabs.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001828345
|
oai_dc
|
Effects of cyclic loading on the long-term deflection of prestressed concrete beams
|
Effects of cyclic loading on the long-term deflection of prestressed concrete beams
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Lihai Zhang(The University of Melbourne); Priyan Mendis(The University of Melbourne); Wong Chon Hon(The University of Melbourne); Sam Fragomeni(Victoria University); Nelson Lam(The University of Melbourne); Yilun Song(The University of Melbourne)"
] |
Creep and shrinkage have pronounced effects on the long-term deflection of prestressed concrete members. Under repeated loading, the rate of creep in prestressed concrete members is often accelerated. In this paper, an iterative computational procedure based on the well known Model B3 for creep and shrinkage was developed to predict the time-dependent deflection of partially prestressed concrete members. The developed model was validated using the experimental observed deflection behavior of a simply supported partially prestressed concrete beam under repeated loading. The validated model was then employed to make predictions of the long-term deflection of the prestressed beams under a variety of conditions (e.g., water cement ratio, relatively humidity and time at drying). The simulation results demonstrate that ignoring creep and shrinkage could lead to significant underestimation of the long-term deflection of a prestressed concrete member. The model will prove useful in reducing the long-term deflection of the prestressed concrete members via the optimal selection of a concrete mix and prestressing forces.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001845995
|
oai_dc
|
Application of direct tension force transfer model with modified fixed-angle softened-truss model to finite element analysis of steel fiber-reinforced concrete members subjected to Shear
|
Application of direct tension force transfer model with modified fixed-angle softened-truss model to finite element analysis of steel fiber-reinforced concrete members subjected to Shear
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"이득행(서울시립대학교); 황진하(서울시립대학교); 주현진(서울시립대학교); 김강수(서울시립대학교)"
] |
Steel fiber-reinforced concrete (SFRC) is known as one of the efficient modern composites that can greatly enhance the material performance of cracked concrete in tension. Such improved tensile resistance mechanism at crack interfaces in SFRC members can be heavily influenced by methodologies of treatments of crack direction. While most existing studies have focused on developing the numerical analysis model with the rotating-angle theory, there are only few studies on finite element analysis models with the fixed-angle model approach. According to many existing experimental studies, the direction of principal stress rotated after the formation of initial fixed-cracks, but it was also observed that new cracks with completely different angles relative to the initial crack direction very rarely occurred. Therefore, this study introduced the direct tension force transfer model (DTFTM), in which tensile resistance of the fibers at the crack interface can be easily estimated, to the nonlinear finite element analysis algorithm with the fixed-angle theory, and the proposed model was also verified by comparing the analysis results to the SFRC shear panel test results. The secant modulus method adopted in this study for iterative calculations in nonlinear finite element analysis showed highly stable and fast convergence capability when it was applied to the fixed-angle theory. The deviation angle between the principal stress direction and the fixed-crack direction significantly increased as the tensile stresses in the steel fibers at crack interfaces increased, which implies that the deviation angle is very important in the estimation of the shear behavior of SFRC members.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001845992
|
oai_dc
|
Chloride penetration resistance of concrete containing ground fly ash, bottom ash and rice husk ash
|
Chloride penetration resistance of concrete containing ground fly ash, bottom ash and rice husk ash
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Somchai Inthata(Rajabhat Mahasarakham University); Raungrut Cheerarot(Rajabhat Mahasarakham University)"
] |
This research presents the effect of various ground pozzolanic materials in blended cement concrete on the strength and chloride penetration resistance. An experimental investigation dealing with concrete incorporating ground fly ash (GFA), ground bottom ash (GBA) and ground rice husk ash (GRHA). The concretes were mixed by replacing each pozzolan to Ordinary Portland cement at levels of 0%, 10%, 20% and 40% by weight of binder. Three different water to cement ratios (0.35, 0.48 and 0.62) were used and type F superplasticizer was added to keep the required slump. Compressive strength and chloride permeability were determined at the ages of 28, 60, and 90 days. Furthermore, using this experimental database, linear and nonlinear multiple regression techniques were developed to construct a mathematical model of chloride permeability in concretes. Experimental results indicated that the incorporation of GFA, GBA and GRHA as a partial cement replacement significantly improved compressive strength and chloride penetration resistance. The chloride penetration of blended concrete continuously decreases with an increase in pozzolan content up to 40% of cement replacement and yields the highest reduction in the chloride permeability. Compressive strength of concretes incorporating with these pozzolans was obviously higher than those of the control concretes at all ages. In addition, the nonlinear technique gives a higher degree of accuracy than the linear regression based on statistical parameters and provides fairly reasonable absolute fraction of variance (R2) of 0.974 and 0.960 for the charge passed and chloride penetration depth, respectively.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001846001
|
oai_dc
|
Performance of adding waste glass and sewage sludge to reservoir-sediment aggregates
|
Performance of adding waste glass and sewage sludge to reservoir-sediment aggregates
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ing-Jia Chiou(Taoyuan Innovation Institute of Technology); Chin-Ho Chen(National Taipei University of Education); Chia-Ling Lin(National Taipei University of Education)"
] |
Accumulated annual reservoir sedimentation in Taiwan was 14.6 million m3 in 2010, seriously endangering reservoir safety and the water supply. In addition, the sintering temperature of reservoir-sediment aggregates (RSAs) is very high, and very energy consuming consequently. Therefore, to explore the effects of admixtures on sintering behavior and performance of the aggregates, two different admixtures are blended, waste-glass and municipal sewage sludge, into reservoir sediment to make artificial aggregates. Experimental results show that the lightweight characteristics of waste-glass/reservoir-sediment aggregates (WGRSAs) are more significant than those of sewage sludge/reservoir-sediment aggregates (SSRSAs). Moreover, as sintering temperature increases, the specific gravity of WGRSAs drops more apparently. The optimum sintering temperature of pure reservoir-sediment aggregates (PRSAs), SSRSAs, and WGRSAs was 1150°C, 1100°C, and 1050°C, respectively. The PRSAs are normal weight with better strength; the WGRSAs are lightweight and energy-saving; and the SSRSAs are lightweight with normal strength.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001846003
|
oai_dc
|
A simplified method to determine the chloride migration coefficient of concrete by the electric current in steady state
|
A simplified method to determine the chloride migration coefficient of concrete by the electric current in steady state
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"K.T. Lin(National Taiwan Ocean University); C.C. Yang(National Taiwan Ocean University)"
] |
This study presents a rapid method for determining the steady state migration coefficient of concrete by measuring the electric current. This study determines the steady state chloride migration coefficient using the accelerated chloride migration test (ACMT). There are two stages to obtain the chloride migration coefficient. The first stage, the steady-state condition was obtainedfrom the initial electric current at the beginning of ACMT. The second stage, the average electrical current in the steady state condition was used to determine the steadystate chloride migration coefficient. The chloride migration coefficient can be determined from the average steady state current to avoid sampling and analyzing chlorides during the ACMT.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001845998
|
oai_dc
|
Assessment of some parameters of corrosion initiation prediction of reinforced concrete in marine environments
|
Assessment of some parameters of corrosion initiation prediction of reinforced concrete in marine environments
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Faramarz Moodi(Amirkabir University of technology); Aliakbar Ramezanianpour(Amirkabir University of technology); Ehsan Jahangiri(Amirkabir University of technology)"
] |
Chloride ion ingress is one of the major problems that affect the durability of concrete structures such as bridge decks, concrete pavements, and other structures exposed to harsh saline environments. Therefore, durability based design of concrete structures in severe condition has gained great significance in recent decades and various mathematical models for estimating the service life of rein-forced concrete have been proposed. In spite of comprehensive researches on the corrosion of rein-forced concrete, there are still various controversial concepts in quantitation of durability parameters such as chloride diffusion coefficient and surface chloride content. Effect of environment conditions on the durability of concrete structures is one of the most important issues. Hence, regional investigations are necessary for durability based design and evaluation of the models. Persian Gulf is one of the most aggressive regions of the world because of elevated temperature and humidity as well as high content of chloride ions in seawater. The aim of this study is evaluation of some parameters of durability of RC structures in marine environment from viewpoint of corrosion initiation. For this purpose, some experiments were carried out on the real RC structures and in laboratory. The result showed that various uncertainties in parameters of durability were existed.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001846002
|
oai_dc
|
Prediction of temperature distribution in hardening silica fume-blended concrete
|
Prediction of temperature distribution in hardening silica fume-blended concrete
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"왕소용(강원대학교)"
] |
Silica fume is a by-product of induction arc furnaces and has long been used as a mineral admixture to produce high-strength, high-performance concrete. Due to the pozzolanic reaction between calcium hydroxide and silica fume, compared with that of Portland cement, the hydration of concrete containing silica fume is much more complex. In this paper, by considering the production of calcium hydroxide in cement hydration and its consumption in the pozzolanic reaction, a numerical model is proposed to simulate the hydration of concrete containing silica fume. The heat evolution rate of silica fume concrete is determined from the contribution of cement hydration and the pozzolanic reaction. Furthermore, the temperature distribution and temperature history in hardening blended concrete are evaluated based on the degree of hydration of the cement and the mineral admixtures. The proposed model is verified through experimental data on concrete with different water-to-cement ratios and mineral admixture substitution ratios.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001845994
|
oai_dc
|
Fracture property of steel fiber reinforced concrete at early age
|
Fracture property of steel fiber reinforced concrete at early age
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chuan-Qing Fu(Zhejiang Universityof Technology); Qin-yong Ma(Anhui University of Science and Technology); Xianyu Jin(Zhejiang University); A.A. Shah(Sarhad University); Ye Tian(Zhejiang University)"
] |
This research is focused on obtaining the fracture property of steel fiber reinforced concrete(SFRC) specimens at early ages of 1, 2, 3 and 7-day, respectively. For this purpose, three point bending tests of nine groups of SFRC beams with notch of 40mm depth and different steel fiber ratios were conducted. The experimental results of early age specimens were compared with the 28-day hardened SFRC specimens. The test results indicated that the steel fiber ratios and curing age significantly influenced the fracture properties of SFRC. A reasonable addition of steel fiber improved the fracture toughness of SFRC, while the fracture energy of SFRC developed with curing age. Moreover, a quadratic relationship between splitting strength and fracture toughness was established based on the experiment results. Additionally, afinite element (FE) method was used to investigate the fracture properties of SFRC.A comparison between the FE analysis and experiment results was also made. The numerical analysis fitted well with the test results, and further details on the failure behaviors of SFRC could be revealed by the suggested numerical simulation method.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001845990
|
oai_dc
|
Nonlinear time history analysis of a pre-stressed concrete containment vessel model under Japan’s March 11 earthquake
|
Nonlinear time history analysis of a pre-stressed concrete containment vessel model under Japan’s March 11 earthquake
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Zuo-zhou Zhao(Zhejiang University); An Duan(Zhejiang Universit); Ju Che(Zhejiang Universit); Jia-ru Qian(Tsinghua University); Wei-liang Jin(Zhejiang University)"
] |
To evaluate the behavior of the advanced unbonded pre-stressed concrete containment vessel (UPCCV) for one typical China nuclear power plant under Japan’s March 11 earthquake, five nonlinear time history analysis and a nonlinear static analysis of a 1:10 scale UPCCV structure have been carried out with MSC.MARC finite element program. Comparisons between the analytical and experimental results demonstrated that the developed finite element model can predict the earthquake behavior of the UPCCV with fair accuracy. The responses of the 1:10 scale UPCCV subjected to the 11 March 2011 Japan earthquakes recorded at the MYG003 station with the peak ground acceleration (PGA) of 781 gal and at the MYG013 station with the PGA of 982 gal were predicted by the dynamic analysis. Finally, a static analysis was performed to seek the ultimate load carrying capacity for the 1:10 scale UPCCV.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001846004
|
oai_dc
|
Effective compressive strength of strut in CFRP-strengthened reinforced concrete deep beams following ACI 318-11
|
Effective compressive strength of strut in CFRP-strengthened reinforced concrete deep beams following ACI 318-11
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mohammad Panjehpour(Universiti Putra Malaysia); Abang Abdullah Abang Ali(Universiti Putra Malaysia); Yen Lei Voo(DURA Technology Sdn Bhd); Farah Nora Aznieta(Universiti Putra Malaysia)"
] |
Strut-and-tie model (STM) has been recommended by many codes and standards as a rationalmodel for discontinuity regions in structural members. STM has been adopted in ACI building code foranalysis of reinforced concrete (RC) deep beams since 2002. However, STM recommended by ACI 318-11is only applicable for analysis of ordinary RC deep beams. This paper aims to develop the STM for CFRPstrengthened RC deep beams through the strut effectiveness factor recommended by ACI 318-11. Two setsof RC deep beams were cast and tested in this research. Each set consisted of six simply-supportedspecimens loaded in four-point bending. The first set had no CFRP strengthening while the second wasstrengthened by means of CFRP sheets using two-side wet lay-up system. Each set consisted of six RC deepbeams with shear span to effective depth ratio of 0.75, 1.00, 1.25, 1.50, 1.75, and 2.00.The value of struteffectiveness factor recommended by ACI 318-11 is modified using a proposed empirical relationship in thisresearch. The empirical relationship is established based on shear span to effective depth ratio.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001751741
|
oai_dc
|
Structural optimization and proposition of pre-sizing parameters for beams in reinforced concrete buildings
|
Structural optimization and proposition of pre-sizing parameters for beams in reinforced concrete buildings
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Guilherme Fleith de Medeiros(University of Passo Fundo); Moacir Kripka(University of Passo Fundo)"
] |
The aim of the present paper is to show the application of optimization strategies for the cost of beams in reinforced concrete buildings and to propose pre-sizing parameters. In order for these goals to be met, an optimization software program was developed. The program combines the analysis of structures by the grid model, reinforced concrete sizing, and the simulated annealing optimization heuristic. Sizing is compliant with the NBR 6118 (2007) Brazilian standard, according to which flexural, shearing, torsion, and web reinforcements and serviceability limit states (deflection and crack width limitation) are checked. Besides the dimensions of the situations mentioned above, the influence the cost of each material (steel, concrete and formwork) has on the overall cost of structures was also determined.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001751737
|
oai_dc
|
Genetic algorithm in mix proportion design of recycled aggregate concrete
|
Genetic algorithm in mix proportion design of recycled aggregate concrete
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"박원준(강원대학교); T. Noguchi(the University of Tokyo); 이한승(한양대학교)"
] |
To select a most desired mix proportion that meets required performances according to the quality of recycled aggregate, a large number of experimental works must be carried out. This paper proposed a new design method for the mix proportion of recycled aggregate concrete to reduce the number of trial mixes. Genetic algorithm is adapted for the method, which has been an optimization technique to solve the multicriteria problem through the simulated biological evolutionary process. Fitness functions for the required properties of concrete such as slump, density, strength, elastic modulus, carbonation resistance, price and carbon dioxide emission were developed based on statistical analysis on conventional data or adapted from various early studies. Then these fitness functions were applied in the genetic algorithm. As a result, several optimum mix proportions for recycled aggregate concrete that meets required performances were obtained.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001751740
|
oai_dc
|
Application of artificial neural networks (ANNs) and linear regressions (LR) to predict the deflection of concrete deep beams
|
Application of artificial neural networks (ANNs) and linear regressions (LR) to predict the deflection of concrete deep beams
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mohammad Mohammadhassani(University of Malaya); Hossein Nezamabadi-Pour(Shahid Bahonar University of Kerman); Mohd. Zamin Jumaat(University of Malaya); Mohammed Jameel(University of Malaya); Arul M S Arumugam(University of Malaya)"
] |
This paper presents the application of artificial neural network (ANN) to predict deep beam deflection using experimental data from eight high-strength-self-compacting-concrete (HSSCC) deep beams. The optimized network architecture was ten input parameters, two hidden layers, and one output. The feed forward back propagation neural network of ten and four neurons in first and second hidden layers using TRAINLM training function predicted highly accurate and more precise load-deflection diagrams compared to classical linear regression (LR). The ANN’s MSE values are 40 times smaller than the LR’s. The test data R value from ANN is 0.9931; thus indicating a high confidence level.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001751738
|
oai_dc
|
Coupled diffusion of multi-component chemicals in nonsaturated concrete
|
Coupled diffusion of multi-component chemicals in nonsaturated concrete
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Nattapong Damrongwiriyanupap(University of Phayao); Linyuan Li(University of New Hampshire); Yunping Xi(University of Colorado at Boulder)"
] |
A comprehensive simulation model for the transport process of fully coupled moisture and multispecies in non-saturated concrete structures is proposed. The governing equations of moisture and ion diffusion are formulated based on Fick’s law and the Nernst-Planck equation, respectively. The governing equations are modified by explicitly including the coupling terms corresponding to the coupled mechanisms. The ionic interaction-induced electrostatic potential is described by electroneutrality condition. The model takes into account the two-way coupled effect of moisture diffusion and ion transport in concrete. The coupling parameters are evaluated based on the available experimental data and incorporated in the governing equations. Differing from previous researches, the material parameters related to moisture diffusion and ion transport in concrete are considered not to be constant numbers and characterized by the material models that account for the concrete mix design parameters and age of concrete. Then, the material models are included in the numerical analysis and the governing equations are solved by using finite element method. The numerical results obtained from the present model agree very well with available test data. Thus, the model can predict satisfactorily the ingress of deicing salts into non-saturated concrete.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001751739
|
oai_dc
|
Quantitative solution of size and dosage of capsules for self-healing of cracks in cementitious composites
|
Quantitative solution of size and dosage of capsules for self-healing of cracks in cementitious composites
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Haifeng Yuan(Southeast University); Huisu Chen(Southeast University)"
] |
Self-healing (SH) technology of cracking is becoming a promising solution to improve the durability of cement based composites. However, little formula are available in the literature on determining the size and dosage of the self-healing capsules. Supposed that SH capsules will be broken and activated when they met cracks, a theoretical solution is developed to calculate the appropriate length of SH capsules based on Buffon’s needle model. Afterwards, a method to calculate the dosage of capsules was proposed in terms of stereological theory. The reliability of the above mentioned theoretical methods was verified by computer simulation. An experiment of self-healing in mortar was performed as well, by which the theoretical models were verified.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001820042
|
oai_dc
|
Seismic assessment of R/C residential buildings with infill walls in Turkey
|
Seismic assessment of R/C residential buildings with infill walls in Turkey
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Kasim Armagan Korkmaz(Istanbul Technical University,); Ali Haydar Kayhan(Pamukkale University); Taner Ucar(Dokuz Eylul University)"
] |
In 1999 Marmara and 2011 Van earthquakes in Turkey, majority of the existing buildings either sustained severe damage or collapsed. These buildings include masonry infill walls in both the interior and exterior R/C frames. The material of the masonry infill is the main variant, ranging from natural stones to bricks and blocks. It is demanding to design these buildings for satisfactory structural behavior. In general, masonry infill walls are considered by its weights not by interaction between walls and frames. In this study, R/C buildings with infill walls are considered in terms of structural behavior. Therefore, 5 and 8-story R/C buildings are regarded as the representative models in the analyses. The R/C representative buildings, both with and without infill walls were analyzed to determine the effects of structural behavior change. The differences in earthquake behavior of these representative buildings were investigated to determine the effects of infill walls leading structural capacity. First, pushover curves of the representative buildings were sketched. Aftermath, time history analyses were carried out to define the displacement demands. Finally, fragility analyses were performed. Throughout the fragility analyses, probabilistic seismic assessment for R/C building structures both with and without infill walls were provided. In this study, besides the deterministic assessment methodology, a probabilistic approach was followed to define structural effect of infill walls under seismic loads.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001820033
|
oai_dc
|
Modelling reinforced concrete beams under mixed shear-tension failure with different continuous FE approaches
|
Modelling reinforced concrete beams under mixed shear-tension failure with different continuous FE approaches
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ireneusz Marzec(Gdansk University of Technology); Łukasz Skarżyńsk(Gdansk University of Technology); Jerzy Bobiński(Gdansk University of Technology); Jacek Tejchman(Gdansk University of Technology)"
] |
The paper presents quasi-static numerical simulations of the behaviour of short reinforced concrete beams without shear reinforcement under mixed shear-tension failure using the FEM and four various constitutive continuum models for concrete. First, an isotropic elasto-plastic model with a Drucker-Prager criterion defined in compression and with a Rankine criterion defined in tension was used. Next, an anisotropic smeared crack and isotropic damage model were applied. Finally, an elasto-plastic-damage model was used. To ensure mesh-independent FE results, to describe strain localization in concrete and to capture a deterministic size effect, all models were enhanced in a softening regime by a characteristic length of micro-structure by means of a non-local theory. Bond-slip between concrete and reinforcement was considered. The numerical results were directly compared with the corresponding laboratory tests performed by Walraven and Lehwalter (1994). The advantages and disadvantages of enhanced models to model the reinforced concrete behaviour were outlined.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001820035
|
oai_dc
|
Estimation of compression strength of polypropylene fibre reinforced concrete using artificial neural networks
|
Estimation of compression strength of polypropylene fibre reinforced concrete using artificial neural networks
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"R. Tugrul Eredm(Celal Bayar University); Erkan Kantar(Celal Bayar University); Engin Gucuyen(Celal Bayar University); Özgür ANIL(Gazi University)"
] |
In this study, Artificial Neural Networks (ANN) analysis is used to predict the compression strength of polypropylene fibre mixed concrete. Polypropylene fibre admixture increases the compression strength of concrete to a certain extent according to mix proportion. This proportion and homogenous distribution are important parameters on compression strength. Determination of compression strength of fibre mixed concrete is significant due to the veridicality of capacity calculations. Plenty of experiments shall be completed to state the compression strength of concrete which have different fibre admixture. In each case, it is known that performing the laboratory experiments is costly and time-consuming. Therefore, ANN analysis is used to predict the 7 and 28 days of compression strength values. For this purpose, 156 test specimens are produced that have 26 different types of fibre admixture. While the results of 120 specimens are used for training process, 36 of them are separated for test process in ANN analysis to determine the validity of experimental results. Finally, it is seen that ANN analysis predicts the compression strength of concrete successfully.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001820046
|
oai_dc
|
A study on the fire performance and heat transfer of the HPC column with fiber-cocktail in ISO fire under loading condition
|
A study on the fire performance and heat transfer of the HPC column with fiber-cocktail in ISO fire under loading condition
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"김형준(한국건설기술연구원); 김흥렬(한국건설기술연구원); 권기혁(서울시립대학교); 민병열(화재안전연구센터); 조범연(한국건설기술연구원); 권인규(강원대학교)"
] |
In this study, experiment and numerical analysis were conducted to identify the heat transfer characteristics and behavior of high-strength concrete upon a fire. The numerical analysis was employed to forecast the characteristics and properties of the high-strength concrete upon a fire, which can not be accomplished through a fire test due to the specific conditions and restrictions associated with the test. The result of the numerical analysis was compared with that of the test to verify the reliability of the analysis. In the numerical analysis of the heat transfer characteristics and behavior of 80 and 100 MPa high-strength concrete upon a fire, the commercial software of ABAQUS(V.6.8) was used. It was observed from the experiment that the contraction of the concrete with fiber-cocktail was mitigated by 25~55 % compared with that without fiber-cocktail because the fiber controlled the heat transfer of the concrete and thus improved the fire-resistance performance of the column.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001820040
|
oai_dc
|
Computer based FEM stabilization of oxygen transport model for material and energy simulation in corroding reinforced concrete
|
Computer based FEM stabilization of oxygen transport model for material and energy simulation in corroding reinforced concrete
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Raja Rizwan Hussain(College of Engineering at King Saud Univ)"
] |
This paper unveils a new computer based stabilization methodology for automated modeling analysis and its experimental verification for corrosion in reinforced concrete structures under the effect of varying oxygen concentration. Various corrosion cells with different concrete compositions under four different environmental conditions (air dry, submerged, 95% R.H and alternate wetting-drying) have been investigated under controlled laboratory conditions.The results of these laboratory tests were utilized with an automated computer-aided simulation model. This model based on mass and energy stabilization through the porous media for the corrosion processwas coupled with modified stabilization methodology. By this coupling, it was possible to predict, maintain and transfer the influence of oxygen concentration on the corrosion rate of the reinforcement in concrete under various defined conditions satisfactorily. The variation in oxygen concentration available for corrosion reaction has been taken into account simulating the actual field conditions such as by varying concrete cover depth, relative humidity, water-cement ratio etc. The modeling task has been incorporated by the use of a computer based durability model as a finite element computational approach for stabilizing the effect of oxygen on corrosion of reinforced concrete structures.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001820043
|
oai_dc
|
Predicting diagonal cracking strength of RC slender beams without stirrups using ANNs
|
Predicting diagonal cracking strength of RC slender beams without stirrups using ANNs
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Riza S.O. Keskin(Yildiz Technical University); Guray Arslana(Yildiz Technical University)"
] |
Numerous studies have been conducted to understand the shear behavior of reinforced concrete (RC) beams since it is a complex phenomenon. The diagonal cracking strength of a RC beam is critical since it is essential for determining the minimum amount of stirrups and the contribution of concrete to the shear strength of the beam. Most of the existing equations predicting the diagonal cracking strength of RC beams are based on experimental data. A powerful computational tool for analyzing experimental data is an artificial neural network (ANN). Its advantage over conventional methods for empirical modeling is that it does not require any functional form and it can be easily updated whenever additional data is available. An ANN model was developed for predicting the diagonal cracking strength of RC slender beams without stirrups. It is shown that the performance of the ANN model over the experimental data considered in this study is better than the performances of six design code equations and twelve equations proposed by various researchers. In addition, a parametric study was conducted to study the effects of various parameters on the diagonal cracking strength of RC slender beams without stirrups upon verifying the model.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART001820037
|
oai_dc
|
Modelling of the effects of alkali-aggregate reaction in reinforced concrete structures
|
Modelling of the effects of alkali-aggregate reaction in reinforced concrete structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S. Pietruszcza(McMaster University); R. Ushaksaraei(McMaster University); V. Gocevski(Hydro-Quebec)"
] |
This paper deals with application of a non-linear continuum model for reinforced concrete affected by alkali-aggregate reaction (AAR) to analysis of some nuclear structures. The macroscopic behaviour of the material affected by AAR is described by incorporating a homogenization/averaging procedure. The formulation addresses the main stages of the deformation process, i.e., a homogeneous deformation mode as well as that involving localized deformation, associated with formation of macrocracks. The formulation is applied to examine the mechanical behaviour of some reinforced concrete structures in nuclear power facilities located in Quebec (Canada). First, a containment structure is analyzed subjected to 45 years of continuing AAR. Later, an inelastic analysis is carried out for the spent fuel pool taking into account the interaction with the adjacent jointed rock mass foundation. In the latter case, the structure is said to be subjected to continuing AAR that is followed by a seismic event.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001820039
|
oai_dc
|
Evaluating the bond strength between concrete substrate and repair mortars with full-factorial analysis
|
Evaluating the bond strength between concrete substrate and repair mortars with full-factorial analysis
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Kamile Tosun Felekoglu(Dokuz Eylul University); Burcu Felekoglu(Dokuz Eylul University); A. Serdar Tasan(Dokuz Eylul University); Burak Felekoglu(Dokuz Eylul University)"
] |
Concrete structures need repairing due to various reasons such as deteriorative effects, overloading, poor quality of workmanship and design failures. Cement based repair mortars are the most widely used solutions for concrete repair applications. Various factors may affect the bond strength between concrete substrate and repair mortars. In this paper, the effects of polymer additives, strength of the concrete substrate, surface roughness, surface wetness and aging on the bond between concrete substrate and repair mortar has been investigated. Full factorial experimental design is employed to investigate the main and interaction effects of these factors on the bond strength. Analysis of variance (ANOVA) under design of experiments (DOE) in Minitab 14 Statistical Software is used for the analysis. Results showed that the interaction bond strength is higher when the application surface is wet and strength of the concrete substrate is comparatively high. According to the results obtained from the analysis, the most effective repair mortar additive in terms of bonding efficiency was styrene butadiene rubber (SBR) within the investigated polymers and test conditions. This bonding ability improvement can be attributed to the self-flowing ability, high flexural strength and comparatively low air content of SBR modified repair mortars. On the other hand, styrene acrylate rubber (SAR) modified mortars was found incompatible with the concrete substrate.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001751729
|
oai_dc
|
Assessment of 3D earthquake response of the Arhavi Highway Tunnel considering soil-structure interaction
|
Assessment of 3D earthquake response of the Arhavi Highway Tunnel considering soil-structure interaction
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Barış SEVİM(Yıldız Technical University)"
] |
This paper describes earthquake response of the Arhavi Highway Tunnel its geometrical properties, 3D finite element model and the linear time history analyses under a huge ground motion considering soil-structure interaction. The Arhavi Highway Tunnel is one of the tallest tunnels constructed in the Black Sea region of Turkey as part of the Coast Road Project. The tunnel has two tubes and each of them is about 1000 m tall. In the study, lineartime history analyses of the tunnel are performed applying northsouth, east-west and up accelerations components of 1992 Erzincan, Turkey ground motion. In the time history analyses, Rayleigh damping coefficients are calculated using main natural frequency obtained from modal analysis. Element matrices are computed using the Gauss numerical integration technique. The Newmark method is used in the solution of the equation of motion. Because of needed too much memory for the analyses, the first 10 second of the ground motions, which is the most effective duration, is taken into account in calculations. The results obtained 3D finite element model are presented. In addition, the displacement and stress results are observed to be allowable level of the concrete material during the earthquakes.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001751726
|
oai_dc
|
Shear behavior of reinforced HPC beams made of a low cement content without shear reinforcements
|
Shear behavior of reinforced HPC beams made of a low cement content without shear reinforcements
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chao-Wei Tang(Cheng-Shiu University); Yu-Ping Chen(Cheng Shiu University); How-Ji Chen(National Chung-Hsing University); Chung-Ho Huang(Dahan Institute of Technology); Tsang-Hao Liu(AU Optronics Corporation)"
] |
High-performance concrete (HPC) usually has higher paste and lower coarse aggregate volumes than normal concrete. The lower aggregate content of HPC can affect the shear capacity of concrete members due to the formation of smooth fractured surfaces and the subsequent development of weak interface shear transfer. Therefore, an experimental investigation was conducted to study the shear strength and cracking behavior of full-scale reinforced beams made with low-cement-content high-performance concrete (LcHPC) as well as conventional HPC. A total of fourteen flexural reinforced concrete (RC) beams without shear reinforcements were tested under a two-point load until shear failure occurred. The primary design variables included the cement content, the shear span to effective depth ratio (a/d), and the tensile steel ratio (ρw). The results indicate that LcHPC beams show comparable behaviors in crack and ultimate shear strength as compared with conventional HPC beams. Overall, the shear strength of LcHPC beams was found to be larger than that of corresponding HPC beams, particularly for an a/d value of 1.5. In addition, the crack and ultimate shear strength increased as a/d decreased or ρw increased for both LcHPC beams and HPC beams. This investigation established that LcHPC is recommendable for structural concrete applications.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001751731
|
oai_dc
|
Cable layout design of two way prestressed concrete slabs using FEM
|
Cable layout design of two way prestressed concrete slabs using FEM
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ahmad Ali Khan(MANIT, Bhopal); K.K.Pathak(CS&PM Group); N.Dindorkar(MANIT, Bhopal)"
] |
In this paper, a new approach for cable layout design of pre-stressed concrete slabs is presented. To account the cable profile accurately, it is modelled by B-spline. Using the convex hull property of the Bspline, an efficient algorithm has been developed to obtain the cable layout for pre stressed concrete slabs. For finite element computations, tendon and concrete are modelled by 3 noded bar and 20 noded brick elements respectively. The cable concrete interactions are precisely accounted using vector calculus formulae. Using the proposed technique a two way prestressed concrete slab has been successfully designed considering several design criteria.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001751725
|
oai_dc
|
Finite element modelling of FRP-strengthened RC beam-column connections with ANSYS
|
Finite element modelling of FRP-strengthened RC beam-column connections with ANSYS
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Rijun Shrestha(University of Technology Sydney); Bijan Samali(University of Technology Sydney); Scott T. Smith(Southern Cross University)"
] |
There is an abundance of research on the strengthening of reinforced concrete (RC) structural elements such as beams, columns and slabs with fibre reinforced polymer (FRP) composites. Less research by comparison has been conducted on the strengthening of RC beam-column connections and the majority of such research has been predominantly experimental to date. Few existing experimental studies have reported extensive instrumentation of test specimens which in turn makes understanding the behavior of the connections and especially the contributions made by the FRP difficult to ascertain. In addition, there has been even more limited research on the analytical and numerical modelling of FRP-strengthened connections. In this paper, detailed descriptions of key strategies to model FRP-strengthened RC connections with finite elements are provided. An extensively instrumented and comprehensively documented set of experiments on FRP-strengthened connections is firstly presented and finite element models are then constructed using ANSYS. The study shows that the finite element approach is able to capture the overall behavior of the test specimens including the failure mode as well as the behavior of the FRP which will most importantly lead to a detailed understanding of the FRP and the future development of rational analytical models. The finite element models are, however, unable to model the stiffness of the connections with accuracy in the ultimate load range of response.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001751730
|
oai_dc
|
Experimental and numerical investigations of the influence of reducing cement by adding waste powder rubber on the impact behavior of concrete
|
Experimental and numerical investigations of the influence of reducing cement by adding waste powder rubber on the impact behavior of concrete
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mustafa Maher Al-Tayeb(Universiti Sains Malaysia); B.H. Abu Bakar(Universiti Sains Malaysia); Hazizan Md Akil(Universiti Sains Malaysia); Hanafi Ismail(Universiti Sains Malaysia)"
] |
In this study, the effect of reducing cement by proportional addition of waste powder rubber on the performance of concrete under impact three-point bending loading were investigated experimentally and numerically. Concrete specimens were prepared by adding 5%, 10% and 20 % of rubber powder as filler to the mix and decreasing the same percentage of cement. For each case, three beams of 50 mm ×100 mm × 500mm were loaded to failure in a drop-weight impact machine by subjecting them to 20 N weight from 300mm height, while another three similar beams were tested under static load. The bending loaddisplacement behavior was analyzed for the plain and rubberized specimens, under static and impact loads. A three dimensional finite-element method simulation was also performed by using LUSAS V.14 in order to study the impact load-displacement behavior, and the predictions were validated with the experimental results. It was observed that, despite decreasing the cement content, the proportional addition of powder rubber until 10% could yield enhancements in impact tup, inertial load and bending load.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001751728
|
oai_dc
|
Hydration and time-dependent rheology changes of cement paste containing ground fly ash
|
Hydration and time-dependent rheology changes of cement paste containing ground fly ash
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Wei Chen(Wuhan University of Technology); Hao Huang(Wuhan University of Technology)"
] |
The use of ground fly ash in concrete can increase the risk of slump loss due to the drastic surface change of the particles after the grinding treatment and the accelerated reaction compared to the untreated ash. This study is aimed at the early age hydration and time-dependent rheology changes of cement paste containing ground fly ash. An original fly ash is ground into different fineness and the hydration of cement paste containing the ground fly ash is monitored with the ultrasound propagation method. The zeta potentials of the solid particles are measured and the changes of rheological parameters of the cement pastes with time are analyzed with a rheometer. A particle packing model is used to probe packing of the solid particles. The results show that the early age hydration of the paste is strongly promoted by replacing Portland cement with fly ash up to 30 percent (by mass), causing increase of the yield stress of the paste. The viscosity of a paste containing ground fly ash is lower than that containing the untreated ash, which is explained by the denser packing of the solid particles.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001775154
|
oai_dc
|
The anchorage-slip effect on direct displacement-based design of R/C bridge piers for limiting material strains
|
The anchorage-slip effect on direct displacement-based design of R/C bridge piers for limiting material strains
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"P.E. Mergos(Technological Educational Institute)"
] |
Direct displacement-based design (DDBD) represents an innovative philosophy for seismic design of structures. When structural considerations are more critical, DDBD design should be carried on the basis of limiting material strains since structural damage is always strain related. In this case, the outcome of DDBD is strongly influenced by the displacement demand of the structural element for the target limit strains. Experimental studies have shown that anchorage slip may contribute significantly to the total displacement capacity of R/C column elements. However, in the previous studies, anchorage slip effect is either ignored or lumped into flexural deformations by applying the equivalent strain penetration length. In the light of the above, an attempt is made in this paper to include explicitly anchorage slip effect in DDBD of R/C column elements. For this purpose, a new computer program named RCCOLA-DBD is developed for the DDBD of single R/C elements for limiting material strains. By applying this program, more than 300 parametric designs are conducted to investigate the influence of anchorage slip effect as well as of numerous other parameters on the seismic design of R/C members according to this methodology.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001775159
|
oai_dc
|
Predictive modeling of concrete compressive strength based on cement strength class
|
Predictive modeling of concrete compressive strength based on cement strength class
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"V.G. Papadakis(University of Western Greece); S. Demis(University of Patras / AEIPLOUS Institut)"
] |
In the current study, a method for concrete compressive strength prediction (based on cement strength class), incorporated in a software package developed by the authors for the estimation of concrete service life under harmful environments, is presented and validated. Prediction of concrete compressive strength, prior to real experimentation, can be a very useful tool for a first mix screening. Given the fact that lower limitations in strength have been set in standards, to attain a minimum of service life, a strength approach is a necessity. Furthermore, considering the number of theoretical attempts on strength predictions so far, it can be seen that although they lack widespread accepted validity, certain empirical expressions are still widely used. The method elaborated in this study, it offers a simple and accurate, compressive strength estimation, in very good agreement with experimental results. A modified version of the Feret’s formula is used, since it contains only one adjustable parameter, predicted by knowing the cement strength class. The approach presented in this study can be applied on any cement type, including active additions (fly ash, silica fume) and age.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001775158
|
oai_dc
|
Strength design criterion for asymmetrically reinforced RC circular cross-sections in bending
|
Strength design criterion for asymmetrically reinforced RC circular cross-sections in bending
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"E. Hernández-Montes(University of Granada); L.M. Gil-Martín(University of Granada); P. Alameda-Hernández(University of Granada)"
] |
Asymmetrical reinforcement for circular sections in wall piles is an efficient construction component with reduced embodied energy. It has been proven that asymmetrical reinforced wall piles may save more than 50% of the reinforcement than the traditional symmetrically reinforced circular sections. The use of this new type of structural member increases the number of variables in the design problem, which makes its use by engineers more complicated. In order to facilitate the use of the asymmetrically reinforced piles, this paper presents a criterion for the design of this type of structural member. The chosen criterion has been analyzed with the help of flexural capacity-cost curves. The new criterion is similar to the design procedure traditionally used for RC beams.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001775155
|
oai_dc
|
Expanding the classic moment-curvature relation by a new perspective onto its axial strain
|
Expanding the classic moment-curvature relation by a new perspective onto its axial strain
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"T. Petschke(E.T.S.I. de Caminos, Canales y Puertos); H. Corres(E.T.S.I. de Caminos, Canales y Puertos); J.I. Ezeberry(E.T.S.I. de Caminos, Canales y Puertos); A. Pérez1(E.T.S.I. de Caminos, Canales y Puertos); A. Recupero1E.T.S.I. de Caminos, Canales(DIC, UNIME, Messina, Italy)"
] |
The moment-curvature relation for simple bending is a well-studied subject and the classical moment-curvature diagram is commonly found in literature. The influence of axial forces has generally been considered as compression onto symmetrically reinforced cross-sections, thus strain at the reference fiber never has been an issue. However, when dealing with integral structures, which are usually statically indeterminate in different degrees, these concepts are not sufficient. Their horizontal elements are often completely restrained, which, under imposed deformations, leads to moderate compressive or tensile axial forces. The authors propose to analyze conventional beam cross-sections with moment-curvature diagrams considering asymmetrically reinforced cross-sections under combined influence of bending and moderate axial force. In addition a new diagram is introduced that expands the common moment-curvature relation onto the strain variation at the reference fiber. A parametric study presented in this article reveals the significant influence of selected cross-section parameters.
|
토목공학
| null |
kci_detailed_000097.xml
|
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