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|---|---|---|---|---|---|---|---|---|---|---|---|---|
ART002079253
|
oai_dc
|
New experiment recipe for chloride penetration in concrete under water pressure
|
New experiment recipe for chloride penetration in concrete under water pressure
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"윤인석(인덕대학교); 남진원((주)바이텍코리아)"
] |
Chloride penetration is considered as a most crucial factor for the determination of the service life of concrete. A lot of experimental tools for the chloride penetration into concrete have been developed, however, the mechanism was based on only diffusion, although permeability is also main driving forces for the chloride penetration. Permeation reacts on submerged concrete impacting for short to long term durability while capillary suction occurs on only dried concrete for very early time. Furthermore, hydrostatic pressure increases in proportional to measured depth from the surface of water because of the increasing weight of water exerting downward force from above. It is thought, therefore, that the water pressure has a great influence on the chloride penetration and thereby on the service life of marine concrete.In this study, new experiment is designed to examine the effect of water pressure on chloride penetration in concrete quantitatively. As an experiment result, pressure leaded a quick chlorides penetration by a certain depth, while diffusion induced chlorides to penetrate inward slowly. Therefore, it was concluded that chloride should penetrates significantly by water pressure and the phenomena should be accelerated for concrete exposed to deep sea. The research is expected as a framework to define the service life of submerged concrete with water pressure and compute water permeability coefficient of cementitious materials.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002079260
|
oai_dc
|
Effect of prestressing on the natural frequency of PSC bridges
|
Effect of prestressing on the natural frequency of PSC bridges
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"신수봉(인하대학교); 김유희(인하대학교); 이호경((주)한국교량개발연구소)"
] |
Depending on the researcher, the effect of prestressing on the natural frequency of a PSC (prestressed concrete) structure appear to have been interpreted differently. Most laboratory tests on PSC beams available showed that the natural frequency is increased appreciably by prestressing. On the other hand, some other references based on field experience argued that the dynamic response of a PSC structure does not change regardless of the prestressing applied. Therefore, the deduced conclusions are inconsistent. Because an experiment with and without prestressing is a difficult task on a full size PSC bridge, the change in natural frequency of a PSC bridge due to prestressing may not be examined through field measurements. The study examined analytically the effects of prestressing on the natural frequency of PSC bridges. A finite element program for an undamped dynamic motion of a beamtendon system was developed with additional geometric stiffness. The analytical results confirm that a key parameter in changing the natural frequency due to prestressing is the relative ratio of prestressing to the total weight of the structure rather than the prestressing itself.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002079263
|
oai_dc
|
Mechanical properties and adiabatic temperature rise of low heat concrete using ternary blended cement
|
Mechanical properties and adiabatic temperature rise of low heat concrete using ternary blended cement
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"김시준(경기대학교); 양근혁(경기대학교); 이경호(경기대학교); 이성태(인하공업전문대학)"
] |
This study examined the mechanical properties and adiabatic temperature rise of low-heat concrete developed based on ternary blended cement using ASTM type IV (LHC) cement, ground fly ash (GFA) and limestone powder (LSP). To enhance reactivity of fly ash, especially at an early age, the grassy membrane was scratched through the additional vibrator milling process. The targeted 28-day strength of concrete was selected to be 42 MPa for application to high-strength mass concrete including nuclear plant structures. The concrete mixes prepared were cured under the isothermal conditions of 5°C, 20°C, and 40°C. Most concrete specimens gained a relatively high strength exceeding 10 MPa at an early age, achieving the targeted 28-day strength. All concrete specimens had higher moduli of elasticity and rupture than the predictions using ACI 318-11 equations, regardless of the curing temperature. The peak temperature rise and the ascending rate of the adiabatic temperature curve measured from the prepared concrete mixes were lower by 12% and 32%, respectively, in average than those of the control specimen made using 80% ordinary Portland cement and 20% conventional fly ash.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002079264
|
oai_dc
|
Effect of fiber geometry on the electromagnetic shielding performance of mortar
|
Effect of fiber geometry on the electromagnetic shielding performance of mortar
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"김영준(고려대학교); Dinberu M. Yemam(Korea University); 김백중(고려대학교); 이종구(고려대학교)"
] |
The increased awareness of electromagnetic wave hazards has prompted studies on electromagnetic shielding using conductive materials in the construction industry. Previous studies have explored the effects of the types of conductive materials and their mix proportions on the electromagnetic shielding performance; however, there has been insufficient research on the effect of the geometry of the conductive materials on the electromagnetic shielding performance. Therefore, in this study, the dependence of the electromagnetic shielding performance on the cross-sectional geometry, diameter and length of fibers was investigated. The results showed that the electromagnetic shielding performance improved when the fiber length increased or the diameter decreased, but the effect of the cross-sectional geometry of the fibers was smaller than the effect of the fiber spacing factor.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002079251
|
oai_dc
|
Prediction of thermal stress in concrete structures with various restraints using thermal stress device
|
Prediction of thermal stress in concrete structures with various restraints using thermal stress device
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"차상률(한국과학기술원); 이윤(대전대학교); 안경희(한국과학기술원); 김진근(한국과학기술원)"
] |
Generally, thermal stress induced by hydration heat causes cracking in mass concrete structures, requiring a thorough control during the construction. The prediction of the thermal stress is currently undertaken by means of numerical analysis despite its lack of reliability due to the properties of concrete varying over time. In this paper, a method for the prediction of thermal stress in concrete structures by adjusting thermal stress measured by a thermal stress device according to the degree of restraint is proposed to improve the prediction accuracy. The ratio of stress in concrete structures to stress under complete restraint is used as the degree of restraint. To consider the history of the degree of restraint, incremental stress is predicted by comparing the degree of restraint and the incremental stress obtained by the thermal stress device. Furthermore, the thermal stresses of wall and foundation predicted by the proposed method are compared to those obtained by numerical analysis. The thermal stresses obtained by the proposed method are similar to those obtained by the analysis for structures with internally as well as externally strong restraint. It is therefore concluded that the prediction of thermal stress for concrete structures with various boundary conditions using the proposed method is suggested to be accurate.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002079257
|
oai_dc
|
Numerical evaluation of FRP composite retrofitted reinforced concrete wall subjected to blast load
|
Numerical evaluation of FRP composite retrofitted reinforced concrete wall subjected to blast load
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"남진원((주)바이텍코리아); 윤인석(인덕대학교); 이성태(인하공업전문대학)"
] |
High performance materials such as Fiber Reinforced Plastic (FRP) are often used for retrofitting structures against blast loads due to its ductility and strength. The effectiveness of retrofit materials needs to be precisely evaluated for the retrofitting design based on the dynamic material responses under blast loads.
In this study, the blast resistance of Carbon Fiber Reinforced Plastic (CFRP) and Kevlar/Glass hybrid fabric (K/G) retrofitted reinforced concrete (RC) wall is analyzed by using the explicit analysis code LS-DYNA, which accommodates the high-strain rate dependent material models. Also, the retrofit effectiveness of FRP fabrics is evaluated by comparing the analysis results for non-retrofitted and retrofitted walls. The verification of the analysis is performed through comparisons with the previous experimental results.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002079259
|
oai_dc
|
Analytical performance evaluation of modified inclined studs for steel plate concrete wall subjected to cyclic loads
|
Analytical performance evaluation of modified inclined studs for steel plate concrete wall subjected to cyclic loads
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"임진선(인하대학교); 정영도(포스코건설 R&D Center); 남진원((주)바이텍코리아); Chun-Ho Kim(Joongbu University); 이성태(인하공업전문대학)"
] |
An analytical study was conducted to investigate the effect of the shape and spacing of modified inclined studs used as shear connector between concrete and steel plate on the cyclic behavior of steel plate concrete (SC) shear wall. 9 different analysis cases were adopted to determine the optimized shape and spacing of stud. As the results, the skeleton curves were obtained from the load-displacement hysteresis curves, and the ultimate and yielding strengths were increased as the spacing of studs decrease. In addition, the strength of inclined studs is shown to be bigger compared to that of conventional studs. The damping ratios increased as the decrease of stiffness ratio. Finally, with decreasing the spacing distance of studs, the cumulative dissipated energy was increased and the seismic performance was improved.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002079255
|
oai_dc
|
Analytical study of failure damage to 270,000-kL LNG storage tank under blast loading
|
Analytical study of failure damage to 270,000-kL LNG storage tank under blast loading
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"이상원(연세대학교); Seung Jai Choi(Yonsei University); 김장호(연세대학교)"
] |
The outer tank of a liquefied natural gas (LNG) storage tank is a longitudinally and meridianally pre-stressed concrete (PSC) wall structure. Because of the current trend of constructing larger LNG storage tanks, the pre-stressing forces required to increase wall strength must be significantly increased. Because of the increase in tank sizes and pre-stressing forces, an extreme loading scenario such as a bomb blast or an airplane crash needs to be investigated. Therefore, in this study, the blast resistance performance of LNG storage tanks was analyzed by conducting a blast simulation to investigate the safety of larger LNG storage tanks. Test data validation for a blast simulation of reinforced concrete panels was performed using a specific FEM code, LS-DYNA, prior to a full-scale blast simulation of the outer tank of a 270,000-kL LNG storage tank. Another objective of this study was to evaluate the safety and serviceability of an LNG storage tank with respect to varying amounts of explosive charge. The results of this study can be used as basic data for the design and safety evaluation of PSC LNG storage tanks.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002079250
|
oai_dc
|
Deformation-based Strut-and-Tie Model for reinforced concrete columns subject to lateral loading
|
Deformation-based Strut-and-Tie Model for reinforced concrete columns subject to lateral loading
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"홍성걸(서울대학교); 이수곤(Samsung C&T); 홍성원(서울대학교 공학연구소); 강현구(서울대학교)"
] |
This paper presents a Strut-and-Tie Model for reinforced concrete (RC) columns subject to lateral loading. The proposed model is based on the loading path for the post-yield state, and the geometries of struts and tie are determined by the stress field of post-yield state. The analysis procedure of the Strut-and-Tie Model is that 1) the shear force and displacement at the initial yield state are calculated and 2) the relationship between the additional shear force and the deformation is determined by modifying the geometry of the longitudinal strut until the ultimate limit state. To validate the developed model, the ultimate strength and associated deformation obtained by experimental results are compared with the values predicted by the model. Good agreements between the proposed model and the experimental data are observed.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002079262
|
oai_dc
|
Pozzolanic reaction of the waste glass sludge incorporating precipitation additives
|
Pozzolanic reaction of the waste glass sludge incorporating precipitation additives
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"유일환(고려대학교); 최지선(현대건설); David A. Lange(University of Illinois at Urbana-Champaign); 지광습(고려대학교)"
] |
The waste glass sludge is a waste produced in the glass industry. It is in a dust form and disposed with water. In the disposal process, various cohesive agents are incorporated in order to precipitate the glass particles efficiently. In this paper, we investigate the pozzolanic reaction of the waste glass sludge incorporating precipitation additives experimentally. The consumption of calcium hydroxide, the setting time and the compressive strength and the pore structure were tested for two different types of the waste glass sludge depending on whether precipitation additives were used. It was found that the waste glass sludge incorporating the precipitation additives had a higher pozzolanic potential than the reference waste glass sludge without precipitation additives.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001983122
|
oai_dc
|
Prediction of Hybrid fibre-added concrete strength using artificial neural networks
|
Prediction of Hybrid fibre-added concrete strength using artificial neural networks
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ali Demir(Celal Bayar University)"
] |
Fibre-added concretes are frequently used in large site applications such as slab and airports as well as in bearing system elements or prefabricated elements. It is very difficult to determine the mechanical properties of the fibre-added concretes by experimental methods in situ. The purpose of this study is to develop an artificial neural network (ANN) model in order to predict the compressive and bending strengths of hybrid fibre-added and non-added concretes. The strengths have been predicted by means of the data that has been obtained from destructive (DT) and non-destructive tests (NDT) on the samples. NDTs are ultrasonic pulse velocity (UPV) and Rebound Hammer Tests (RH). 105 pieces of cylinder samples with a dimension of 150 × 300 mm, 105 pieces of bending samples with a dimension of 100x100x400 mm have been manufactured. The first set has been manufactured without fibre addition, the second set with the addition of %0.5 polypropylene and %0.5 steel fibre in terms of volume, and the third set with the addition of %0.5 polypropylene, %1 steel fibre. The water/cement (w/c) ratio of samples parametrically varies between 0.3-0.9. The experimentally measured compressive and bending strengths have been compared with predicted results by use of ANN method.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001983128
|
oai_dc
|
Strength deterioration of reinforced concrete column sections subject to pitting
|
Strength deterioration of reinforced concrete column sections subject to pitting
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Rita Greco(Technical University of Bari); Giuseppe Carlo Marano(Technical University of Bari)"
] |
Chloride induced reinforcement corrosion is widely accepted to be the most frequent mechanism causing premature degradation of reinforced concrete members, whose economic and social consequences are growing up continuously. Prevention of these phenomena has a great importance in structural design, and modern Codes and Standards impose prescriptions concerning design details and concrete mix proportion for structures exposed to different external aggressive conditions, grouped in environmental classes. This paper focuses on reinforced concrete column section load carrying capacity degradation over time due to chloride induced steel pitting corrosion. The structural element is considered to be exposed to marine environment and the effects of corrosion are described by the time degradation of the axial-bending interaction diagram. Because chlorides ingress and consequent pitting corrosion propagation are both time-dependent mechanisms, the study adopts a time-variant predictive approach to evaluate residual strength of corroded reinforced concrete columns at different lifetimes. Corrosion initiation and propagation process is modelled by taking into account all the parameters, such as external environmental conditions, concrete mix proportion, concrete cover and so on, which influence the time evolution of the corrosion phenomenon and its effects on the residual strength of reinforced concrete columns sections.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001983126
|
oai_dc
|
Prediction of RC structure service life from field long term chloride diffusion
|
Prediction of RC structure service life from field long term chloride diffusion
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Majid Safehian(Amirkabir University of Technology); Ali Akbar Ramezanianpour(Amirkabir University of Technology)"
] |
It is well-documented that the major deterioration of coastal RC structures is chloride-induced corrosion. Therefore, regional investigations are necessary for durability based design and evaluation of the proposed service life prdiction models. In this paper, four reinforced concrete jetties exposed to severe marine environment were monitored to assess the long term chloride penetration at 6 months to 96 months. Also, some accelerated durability tests were performed on standard samples in laboratory. As a result, two time-dependent equations are proposed for basic parameters of chloride diffusion into concrete and then the corrosion initiation time is estimated by a developed probabilistic service life model Also, two famous service life prediction models are compared using chloride profiles obtained from structures after about 40 years in the tidal exposure conditions. The results confirm that the influence of concrete quality on diffusion coefficients is related to the concrete pore structure and the time dependence is due to chemical reactions of sea water ions with hydration products which lead a reduction in pore structure. Also, proper attention to the durability properties of concrete may extend the service life of marine structures greater than fifty years, even in harsh environments.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001983130
|
oai_dc
|
Time dependent finite element analysis of steel-concrete composite beams considering partial interaction
|
Time dependent finite element analysis of steel-concrete composite beams considering partial interaction
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Maiga M. Dias(Federal University of Rio Grande do Sul); Jorge L.P. Tamayo(Federal University of Rio Grande do Sul); Inácio B. Morsch(Federal University of Rio Grande do Sul); Armando M. Awruch(Federal University of Rio Grande do Sul)"
] |
A finite element computer code for short-term analysis of steel-concrete composite structures is extended to study long-term effects under service loads, in the present work. Long-term effects are important in engineering design because they influence stress and strain distribution of the structural system and therefore contribute to the increment of deflections in these structures. For creep analysis, a rheological model based on a Kelvin chain, with elements placed in series, was employed. The parameters of the Kelvin chain were obtained using Dirichlet series. Creep and shrinkage models, proposed by the CEB FIP 90, were used. The shear-lag phenomenon that takes place at the concrete slab is usually neglected or not properly taken into account in the formulation of beam-column finite elements. Therefore, in this work, a three-dimensional numerical model based on the assemblage of shell finite elements for representing the steel beam and the concrete slab is used. Stud shear connectors are represented for special beam-column elements to simulate the partial interaction at the slab-beam interface. The two-dimensional representation of the concrete slab permits to capture the non-uniform shear stress distribution in the horizontal plane of the slab due to shear-lag phenomenon. The model is validated with experimental results of two full-scale continuous composite beams previously studied by other authors. Results are given in terms of displacements, bending moments and cracking patterns in order to shown the influence of long-term effects in the structural response and also the potentiality of the present numerical code.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001983124
|
oai_dc
|
Numerical modelling of the damaging behaviour of the reinforced concrete structures by multi-layers beams elements
|
Numerical modelling of the damaging behaviour of the reinforced concrete structures by multi-layers beams elements
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Khebizi Mourad(University of Guelma); Guenfoud Mohamed(University of Guelma)"
] |
A two-dimensional multi-layered finite elements modeling of reinforced concrete structures at non-linear behaviour under monotonic and cyclical loading is presented. The non-linearity material is characterized by several phenomena such as: the physical non-linearity of the concrete and steels materials, the behaviour of cracked concrete and the interaction effect between materials represented by the post-cracking filled. These parameters are taken into consideration in this paper to examine the response of the reinforced concrete structures at the non-linear behaviour. Four examples of application are presented. The numerical results obtained, are in a very good agreement with available experimental data and other numerical models of the literature.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001983125
|
oai_dc
|
Influence of axial load and loading path on the performance of R.C. bridge piers
|
Influence of axial load and loading path on the performance of R.C. bridge piers
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Fouad Kehila(National Earthquake Engineering Research); Hakim Bechtoula(National Earthquake Engineering Researc); Djillali Benaouar(Bab Ezzouar University of Science & Tec)"
] |
Piers are the most vulnerable part of a bridge structure during an earthquake event. During Kobe earthquake in 1995, several bridge piers of the Hanshin Expressway collapsed for more than 600m of the bridge length. In this paper, the most important results of an experimental and analytical investigation of ten reinforced concrete bridge piers specimens with the same cross section subjected to constant axial (or variable) load and reversed (or one direction) cycling loading are presented. The objective was to investigate the main parameters influencing the seismic performance of reinforced concrete bridge piers. It was found that loading history and axial load intensity had a great influence on the performance of piers, especially concerning strength and stiffness degradation as well as the energy dissipation. Controlling these parameters is one of the keys for an ideal seismic performance for a given structure during an eventual seismic event.
Numerical models for the tested specimens were developed and analyzed using SeismoStruct software. The analytical results show reasonable agreement with the experimental ones. The analysis not only correctly predicted the stiffness, load, and deformation at the peak, but also captured the post-peak softening as well. The analytical results showed that, in all cases, the ratio, experimental peak strength to the analytical one, was greater than 0.95.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001983129
|
oai_dc
|
On geometry dependent R-curve from size effect law for concrete-like quasibrittle materials
|
On geometry dependent R-curve from size effect law for concrete-like quasibrittle materials
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yanhua Zhao(Dalian University of Technology); Jian-mei Chang(Inner Mongolia University); Hong-bo Gao(Hainan University)"
] |
R-curve based on the size effect law previously developed for geometrically similar specimens (geometry type III) is extended to geometries with variable depth (geometry type I) as well as with variable notch (geometry type II), where the R-curve is defined as the envelope of the family of critical strain energy release rates from specimens of different sizes. The results show that the extended R-curve for type I tends to be the same for different specimen configurations, while it is greatly dependent on specimen geometry in terms of the initial crack length. Furthermore, the predicted load-deflection responses from the suggested R-curve are found to agree well with the testing results on concrete and rock materials. Besides, maximum loads for type II specimen are predicted well from the extended R-curve.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001983123
|
oai_dc
|
Computational simulations of concrete behaviour under dynamic conditions using elasto-visco-plastic model with non-local softening
|
Computational simulations of concrete behaviour under dynamic conditions using elasto-visco-plastic model with non-local softening
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ireneusz Marzec(Gdansk University of Technology); Jacek Tejchman(Gdansk University of Technology); Andrzej Winnicki(Cracow University of Technology)"
] |
The paper presents results of FE simulations of the strain-rate sensitive concrete beha515viour under dynamic loading at the macroscopic level. To take the loading velocity effect into account, viscosity, stress modifications and inertial effects were included into a rate-independent elasto-plastic formulation. In addition, a decrease of the material stiffness was considered for a very high loading velocity to simulate fragmentation. In order to ensure the mesh-independence and to properly reproduce strain localization in the entire range of loading velocities, a constitutive formulation was enhanced by a characteristic length of micro-structure using a non-local theory. Numerical results were compared with corresponding laboratory tests and available analytical formulae.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001983121
|
oai_dc
|
A meso-scale approach to modeling thermal cracking of concrete induced by water-cooling pipes
|
A meso-scale approach to modeling thermal cracking of concrete induced by water-cooling pipes
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chao Zhang(Wuhan University); Wei Zhou(Wuhan University); Gang Ma(Wuhan University); Chao Hu(Wuhan University); Shaolin Li(Wuhan University)"
] |
Cooling by the flow of water through an embedded cooling pipe has become a common and effective artificial thermal control measure for massive concrete structures. However, an extreme thermal gradient induces significant thermal stress, resulting in thermal cracking. Using a mesoscopic finite-element (FE) mesh, three-phase composites of concrete namely aggregate, mortar matrix and interfacial transition zone (ITZ) are modeled. An equivalent probabilistic model is presented for failure study of concrete by assuming that the material properties conform to the Weibull distribution law. Meanwhile, the correlation coefficient introduced by the statistical method is incorporated into the Weibull distribution formula. Subsequently, a series of numerical analyses are used for investigating the influence of the correlation coefficient on tensile strength and the failure process of concrete based on the equivalent probabilistic model. Finally, as an engineering application, damage and failure behavior of concrete cracks induced by a water-cooling pipe are analyzed in-depth by the presented model. Results show that the random distribution of concrete mechanical parameters and the temperature gradient near water-cooling pipe have a significant influence on the pattern and failure progress of temperature-induced micro-cracking in concrete.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001983127
|
oai_dc
|
Combined strain gradient and concrete strength effects on flexural strength and ductility design of RC columns
|
Combined strain gradient and concrete strength effects on flexural strength and ductility design of RC columns
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"M.T. Chen(The University of Hong Kong); J. C. M. Ho(The University of Hong Kong)"
] |
The stress-strain relationship of concrete in flexure is one of the essential parameters in assessing the flexural strength and ductility of reinforced concrete (RC) columns. An overview of previous research studies revealed that the presence of strain gradient would affect the maximum concrete stress developed in flexure. However, no quantitative model was available to evaluate the strain gradient effect on concrete under flexure. Previously, the authors have conducted experimental studies to investigate the strain gradient effect on maximum concrete stress and respective strain and developed two strain-gradient-dependent factors k3 and ko for modifying the flexural concrete stress-strain curve. As a continued study, the authors herein will extend the investigation of strain gradient effects on flexural strength and ductility of RC columns to concrete strength up to 100 MPa by employing the strain-gradient-dependent concrete stress-strain curve using nonlinear moment-curvature analysis. It was evident from the results that both the flexural strength and ductility of RC columns are improved under strain gradient effect. Lastly, for practical engineering design purpose, a new equivalent rectangular concrete stress block incorporating the combined effects of strain gradient and concrete strength was proposed and validated. Design formulas and charts have also been presented for flexural strength and ductility of RC columns.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002098826
|
oai_dc
|
Empirical modeling of flexural and splitting tensile strengths of concrete containing fly ash by GEP
|
Empirical modeling of flexural and splitting tensile strengths of concrete containing fly ash by GEP
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mustafa Sarıdemir(Nigde University)"
] |
In this paper, the flexural strength (ffs) and splitting tensile strength (fsts) of concrete containing different proportions of fly ash have been modeled by using gene expression programming (GEP). Two GEP models called GEP-I and GEP-II are constituted to predict the ffs and fsts values, respectively. In these models, the age of specimen, cement, water, sand, aggregate, superplasticizer and fly ash are used as independent input parameters. GEP-I model is constructed by 292 experimental data and trisected into 170, 86 and 36 data for training, testing and validating sets, respectively. Similarly, GEP-II model is constructed by 278 experimental data and trisected into 142, 70 and 66 data for training, testing and validating sets, respectively. The experimental data used in the validating set of these models are independent from the training and testing sets. The results of the statistical parameters obtained from the models indicate that the proposed empirical models have good prediction and generalization capability.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002098831
|
oai_dc
|
Impact of temperature cycling on fracture resistance of asphalt concretes
|
Impact of temperature cycling on fracture resistance of asphalt concretes
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Sadjad Pirmohammad(University of Mohaghegh Ardabili); Ahad Kiani(University of Mohaghegh Ardabili)"
] |
Asphalt pavements are exposed to complex weather conditions and vehicle traffic loads leading to crack initiation and crack propagation in asphalt pavements. This paper presents the impact of weather conditions on fracture toughness of an asphalt concrete, prevalently employed in Ardabil road networks, under tensile (mode I) and shear (mode II) loading. An improved semi-circular bend (SCB) specimen was employed to carry out the fracture experiments. These experiments were performed in two different weather conditions namely fixed and cyclic temperatures. The results showed that consideration of the impact of temperature cycling resulted in decreasing the fracture toughness of asphalt concrete significantly.
Furthermore, the fracture toughness was highly affected by loading mode for the both fixed and cyclic temperature conditions studied in this paper. In addition, it was found that the MTS criterion correctly predicts the onset of fracture initiation although this prediction was slightly conservative.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002098832
|
oai_dc
|
Effect of basalt fibers on fracture energy and mechanical properties of HSC
|
Effect of basalt fibers on fracture energy and mechanical properties of HSC
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mehmet E. Arslan(Technology Faculty Düzce University)"
] |
Fracture energy is one of the key parameters reveal cracking resistance and fracture toughness of concrete. The main purpose of this study is to determine fracture behavior, mechanical properties and microstructural analysis of high strength basalt fiber reinforced concrete (HSFRC). For this purpose, threepoint bending tests were performed on notched beams produced using HSFRCs with 12 mm and 24mm fiber length and 1, 2 and 3 kg/m³ fiber content in order to determine the value of fracture energy. Fracture energies of the notched beam specimens were calculated by analyzing load versus crack mouth opining displacement curves by the help of RILEM proposal. The results show that the effects of basalt fiber content and fiber length on fracture energy are very significant. The splitting tensile and flexural strength of HSFRC increased with increasing fiber content whereas a slight drop in flexural strength was observed for the mixture with 24mm fiber length and 3 kg/m³ fiber content. On the other hand, there was no significant effect of fiber addition on the compressive strength and modulus of elasticity of the mixtures. In addition, microstructural analysis of the three components; cement paste, aggregate and basalt fiber were performed based on the Scanning ElectronMicroscopy and Energy-Dispersive X-ray Spectroscopy examinations.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002098830
|
oai_dc
|
Prediction models for compressive strength of concrete with Alkali-activated binders
|
Prediction models for compressive strength of concrete with Alkali-activated binders
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Arkamitra Kar(Birla Institute of Technology and Science-Pilani); Indrajit Ray(The University of theWest Indies); Avinash Unnikrishnan(Portland State University); Udaya B. Halabe(West Virginia University)"
] |
Alkali-activated binder (AAB) is increasingly being considered as an eco-friendly and sustainable alternative to portland cement (PC). The present study evaluates 30 different AAB mixtures containing fly ash and/or slag activated by sodium hydroxide and sodium silicate by correlating their properties from micro to specimen level using regression. A model is developed to predict compressive strength of AAB as a function of volume fractions of microstructural phases (physicochemical properties) and ultrasonic pulse velocity (elastic properties and density). The predicted models are ranked and then compared with the experimental data. The correlations were found to be quite reasonable (R2 = 0.89) for all the mixtures tested and can be used to estimate the compressive strengths for similarAAB mixtures.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002098822
|
oai_dc
|
Optimum design of RC shallow tunnels in earthquake zones using artificial bee colony and genetic algorithms
|
Optimum design of RC shallow tunnels in earthquake zones using artificial bee colony and genetic algorithms
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hasan Tahsin Öztürk(Karadeniz Technical University); Erdem Turkeli(Provincial Organization of Ministry of Environment and Urbanization); Ahmet Durmus(Nuh Naci Yazgan University)"
] |
The main purpose of this study is to perform optimum cost design of cut and cover RC shallow tunnels using Artificial bee colony and genetic algorithms. For this purpose, mathematical expressions of objective function, design variables and constraints for the design of cut and cover RC shallow tunnels were determined. By using these expressions, optimum cost design of the Trabzon Kalekapısı junction underpass tunnel was carried out by using the cited algorithms. The results obtained from the algorithms were compared with the results obtained from traditional design and remarkable saving from the cost of the tunnel was achieved.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002098827
|
oai_dc
|
Probabilistic-based prediction of lifetime performance of RC bridges subject to maintenance interventions
|
Probabilistic-based prediction of lifetime performance of RC bridges subject to maintenance interventions
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hao Tian(Zhejiang Scientific Research Institute of Transport); Fangyuan Li(Tongji University)"
] |
In this paper, a probabilistic- and finite element-based approach to evaluate and predict the lifetime performance of reinforced concrete (RC) bridges undergoing various maintenance actions is proposed with the time-variant system reliability being utilized as a performance indicator. Depending on their structural state during the degradation process, the classical maintenance actions for RC bridges are firstly categorized into four types: Preventive type I, Preventive type II, Strengthening and Replacement.
Preventive type I is used to delay the onset of steel corrosion, Preventive type II can suppress the corrosion process of reinforcing steel, Strengthening is the application of various maintenance materials to improve the structural performance and Replacement is performed to restore the individual components or overall structure to their original conditions. The quantitative influence of these maintenance types on structural performance is investigated and the respective analysis modules are written and inputted into the computer program. Accordingly, the time-variant system reliability can be calculated by the use of Monte Carlo simulations and the updated the program. Finally, an existing RC continuous bridge located in Shanghai, China, is used as an illustrative example and the lifetime structural performance with and without each of the maintenance types are discussed. It is felt that the proposed approach can be applied to various RC bridges with different structural configurations, construction methods and environmental conditions.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002098825
|
oai_dc
|
Statistical flexural toughness modeling of ultra high performance concrete using response surface method
|
Statistical flexural toughness modeling of ultra high performance concrete using response surface method
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mohammad A. Mosaberpanah(Eastern Mediterranean University); Ozgur Eren(Eastern Mediterranean University)"
] |
This paper aims to model the effects of five different variables which includes: cement content (C), the steel fiber amount (F), the silica fume amount (SF), the superplasticizer (SP), the silica fume amount (SF), and the water to cementitious ratio (w/c) on 28 days flexural toughness of Ultra High Performance Concrete (UHPC) as well as, a study on the variable interactions and correlations by using analyze of variance (ANOVA) and response surface methodology (RSM). The variables were compared by fine aggregate mass. The model will be valid for the mixes with 0.18 to 0.32 w/c ratio, 4 to 8 percent steel fiber, 7 to 13 percent cement, 15 to 30 percent silica fume, and 4 to 8 percent superplasticizer by fine aggregate mass.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002098824
|
oai_dc
|
Theoretical and experimental dynamic characteristics of a RC building model for construction stages
|
Theoretical and experimental dynamic characteristics of a RC building model for construction stages
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Temel Turker(Karadeniz Technical University); Alemdar Bayraktar(Karadeniz Technical University)"
] |
Dynamic characteristics, named as natural frequencies, damping ratios and mode shapes, affect the dynamic behavior of buildings and they vary depending on the construction stages. It is aimed to present the effects of construction stages on the dynamic characteristics of reinforced concrete (RC) buildings considering theoretical and experimental investigations. For this purpose, a three-storey RC building model with a 1/2 scale was constructed in the laboratory of Civil Engineering Department at Karadeniz Technical University. The modal testing measurements were performed by using Operational Modal Analysis (OMA) method for the bare frame, brick walled and coated cases of the building model. Randomly generated loads by impact hammer were used to vibrate the building model; the responses were measured by uni-axial seismic accelerometers as acceleration. The building’s modal parameters at these construction stages were extracted from the processed signals using the Enhanced Frequency Domain Decomposition (EFDD) technique. Also, the finite element models of each case were developed and modal analyses were performed.
It was observed from the experimental and theoretical investigations that the natural frequencies of the building model varied depending on the construction stages considerably.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002052207
|
oai_dc
|
Study on moisture transport in concrete in atmospheric environment
|
Study on moisture transport in concrete in atmospheric environment
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Weiping Zhang(Tongji University); Fei Tong(Tongji University); Xianglin Gu(Tongji University); Yunping Xi(Tongji University)"
] |
Moisture transport in concrete in atmospheric environment was studied in this paper. Based on the simplified formula of the thickness of the adsorbed layer, the pore-size distribution function of cement paste was calculated utilizing the water adsorption isotherms. Taking into consideration of the hysteresis effect in cement paste, the moisture diffusivity of cement paste was obtained by the integration of the pore-size distribution. Concrete is regarded as a two-phase composite with cement paste and aggregate, neglecting the moisture diffusivity of aggregate, then moisture diffusivity of concrete was evaluated using the composite theory. Finally, numerical simulation of humidity response during both wetting and drying process was carried out by the finite difference method of partial differential equation for moisture transport, and the numerical results well capture the trend of the measured data.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002052186
|
oai_dc
|
Performance assessment of advanced hollow RC bridge column sections
|
Performance assessment of advanced hollow RC bridge column sections
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"김태훈((주)삼성물산 건설부문); H.Y. Kim(Yeungnam University); S.H. Lee(Samsung Construction & Trading Corporation); J.H. Lee(Yeungnam University); 신현목(성균관대학교)"
] |
This study investigates the performance of advanced hollow reinforced concrete (RC) bridge column sections with triangular reinforcement details. Hollow column sections are based on economic considerations of cost savings associated with reduced material and design moments, as against increased construction complexity, and hence increased labor costs. The proposed innovative reinforcement details are economically feasible and rational, and facilitate shorter construction periods. We tested a model of advanced hollow column sections under quasi-static monotonic loading. The results showed that the proposed triangular reinforcement details were equal to the existing reinforcement details, in terms of the required performance. We used a computer program, Reinforced Concrete Analysis in Higher Evaluation System Technology (RCAHEST), for analysis of the RC structures; and adopted a modified lateral confining effect model for the advanced hollow bridge column sections. Our study documents the testing of hollow RC bridge column sections with innovative reinforcement details, and presents conclusions based on the experimental and analytical findings. Additional full-scale experimental research is needed to refine and confirm the design details, especially for the actual detailing employed in the field.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002052200
|
oai_dc
|
A comparative assessment of bagging ensemble models for modeling concrete slump flow
|
A comparative assessment of bagging ensemble models for modeling concrete slump flow
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hacer Yumurtacı Aydogmus(Alanya Alaaddin Keykubat University); Halil Ibrahim Erdal(Turkish Cooperation and Coordi); Onur Karakurt(Gazi University); Yusuf S. Turkan(Istanbul University); Hamit Erdal(Ataturk University)"
] |
In the last decade, several modeling approaches have been proposed and applied to estimate the high-performance concrete (HPC) slump flow. While HPC is a highly complex material, modeling its behavior is a very difficult issue. Thus, the selection and application of proper modeling methods remain therefore a crucial task. Like many other applications, HPC slump flow prediction suffers from noise which negatively affects the prediction accuracy and increases the variance. In the recent years, ensemble learning methods have introduced to optimize the prediction accuracy and reduce the prediction error. This study investigates the potential usage of bagging (Bag), which is among the most popular ensemble learning methods, in building ensemble models. Four well-known artificial intelligence models (i.e., classification and regression trees CART, support vector machines SVM, multilayer perceptron MLP and radial basis function neural networks RBF) are deployed as base learner. As a result of this study, bagging ensemble models (i.e., Bag-SVM, Bag-RT, Bag-MLP and Bag-RBF) are found superior to their base learners (i.e., SVM, CART, MLP and RBF) and bagging could noticeable optimize prediction accuracy and reduce the prediction error of proposed predictive models.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002052198
|
oai_dc
|
Seismic performance of skewed highway bridges using analytical fragility function methodology
|
Seismic performance of skewed highway bridges using analytical fragility function methodology
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"M. Bayat(Tarbiat Modares University); F. Daneshjoo(Tarbiat Modares University)"
] |
In this study, the seismic performance of skewed highway bridges has been assessed by using fragility function methodology. Incremental Dynamic Analysis (IDA) has been used to prepare complete information about the different damage states of a 30 degree skewed highway bridge. A three dimensional model of a skewed highway bridge is presented and incremental dynamic analysis has been applied. The details of the full nonlinear procedures have also been presented. Different spectral intensity measures are studied and the effects of the period on the fragility curves are shown in different figures. The efficiency, practicality and proficiency of these different spectral intensity measures are compared. A suite of 20 earthquake ground motions are considered for nonlinear time history analysis. It has been shown that, considering different intensity measures (IM) leads us to overestimate or low estimate the damage probability which has been discussed completely.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002052184
|
oai_dc
|
Prediction of initiation time of corrosion in RC using meshless methods
|
Prediction of initiation time of corrosion in RC using meshless methods
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ling Yao(Xi'an Jiaotong University); Lingling Zhang(Xi'an Jiaotong University); Ling Zhang(Xi'an Jiaotong University); Xiaolu Li(Xi'an Jiaotong University)"
] |
Degradation of reinforced concrete (RC) structures due to chloride penetration followed by reinforcement corrosion has been a serious problem in civil engineering for many years. The numerical simulation methods at present are mainly finite element method (FEM) and finite difference method (FDM), which are based on mesh. Mesh generation in engineering takes a long time. In the present article, the numerical solution of chloride transport in concrete is analyzed using radial point interpolation method (RPIM) and element-free Galerkin (EFG). They are all meshless methods. RPIM utilizes radial polynomial basis, whereas EFG uses the moving least-square approximation. A Galerkin weak form on global is used to attain the discrete equation, and four different numerical examples are presented. MQ function and appropriate parameters have been proposed in RPIM. Numerical simulation results are compared with those obtained from the finite element method (FEM) and analytical solutions. Two case of chloride transport in full saturated and unsaturated concrete are analyzed to test the practical applicability and performance of the RPIM and EFG. A good agreement is obtained among RPIM, EFG, and the experimental data. It indicates that RPIM and EFG are reliable meshless methods for prediction of chloride concentration in concrete structures.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002052185
|
oai_dc
|
Modeling of reinforced concrete structural members for engineering purposes
|
Modeling of reinforced concrete structural members for engineering purposes
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jacky Mazars(University Grenoble Alpes); Stéphane Grange(University Grenoble Alpes)"
] |
When approached using nonlinear finite element (FE) techniques, structural analyses generate, for real RC structures, large complex numerical problems. Damage is a major part of concrete behavior, and the discretization technique is critical to limiting the size of the problem. Based on previous work, the μ damage model has been designed to activate the various damage effects correlated with monotonic and cyclic loading, including unilateral effects. Assumptions are formulated to simplify constitutive relationships while still allowing for a correct description of the main nonlinear effects. After presenting classical 2D finite element applications on structural elements, an enhanced simplified FE description including a damage description and based on the use of multi-fiber beam elements is provided. Improvements to this description are introduced both to prevent dependency on mesh size as damage evolves and to take into account specific phenomena (permanent strains and damping, steelconcrete debonding). Applications on RC structures subjected to cyclic loads are discussed, and results lead to justifying the various concepts and assumptions explained.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002052205
|
oai_dc
|
Numerical simulation on structural behavior of UHPFRC beams with steel and GFRP bars
|
Numerical simulation on structural behavior of UHPFRC beams with steel and GFRP bars
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"류두열(The University of British Columbia); Nemkumar Banthia(The University of British Columbia)"
] |
This study simulates the flexural behavior of ultra-high-performance fiber-reinforced concrete (UHPFRC) beams reinforced with steel and glass fiber-reinforced polymer (GFRP) rebars. For this, micromechanics-based modeling was first carried out on the basis of single fiber pullout models considering inclination angle. Two different tension-softening curves (TSCs) with the assumptions of 2-dimensional (2-D) and 3-dimensional (3-D) random fiber orientations were obtained from the micromechanics-based modeling, and linear elastic compressive and tensile models before the occurrence of cracks were obtained from the mechanical tests and rule of mixture. Finite element analysis incorporating smeared crack model was used due to the multiple cracking behaviors of structural UHPFRC beams, and the characteristic length of two times the element width (or two times the average crack spacing at the peak load) was suggested as a result of parametric study. Analytical results showed that the assumption of 2-D random fiber orientation is appropriate to a non-reinforced UHPFRC beam, whereas the assumption of 3-D random fiber orientation is suitable for UHPFRC beams reinforced with steel and GFRP rebars due to disorder of fiber alignment from the internal reinforcements. The micromechanics-based finite element analysis also well predicted the serviceability deflections of UHPFRC beams with GFRP rebars and hybrid reinforcements.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001929899
|
oai_dc
|
Failure criteria of concrete- A review
|
Failure criteria of concrete- A review
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Muthukumar G(BITS); Manoj Kumar(BITS)"
] |
Concrete is a versatile construction material used in many engineering structures. The design ofconcrete structures requires a thorough understanding of their material properties under various loadingconditions. Several experimental investigations have been carried out to examine the behavior of concrete.
This paper is an attempt to summarize the behavioral aspects of concrete under different loading conditions.
Failure models developed out of these experimental investigations are reported in this paper with their meritsand demerits.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001929904
|
oai_dc
|
Factors affecting the properties of recycled concrete by using neural networks
|
Factors affecting the properties of recycled concrete by using neural networks
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Zhen-Hua Duan(The Hong Kong Polytechnic University); Chi-Sun Poon(The Hong Kong Polytechnic University)"
] |
Artificial neural networks (ANN) has been proven to be able to predict the compressive strength and elastic modulus of recycled aggregate concrete (RAC) made with recycled aggregates (RAs) from different sources. However, ANN is itself like a black box and the output from the model cannot generate an exact mathematical model that can be used for detailed analysis. So in this study, sensitivity analysis is conducted to further examine the influence of each selected factor on the output value of the models. This is not only conducive to the determination and selection of the more important factors affecting the results, but also can provide guidance for researchers in adjusting mix proportions appropriately when designing RAC based on the variation of these factors.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001929907
|
oai_dc
|
Predictive models of hardened mechanical properties of waste LCD glass concrete
|
Predictive models of hardened mechanical properties of waste LCD glass concrete
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chien-Chih Wang(Cheng Shiu University); Her-Yung Wang(National Kaohsiung University of Applied Sciences); Chi Huang(National Kaohsiung University of Applied Sciences)"
] |
This paper aims to develop a prediction model for the hardened properties of waste LCD glass that is used in concrete by analyzing a series of laboratory test results, which were obtained in our previous study. We also summarized the testing results of the hardened properties of a variety of waste LCD glass concretes and discussed the effect of factors such as the water-binder ratio (w/b), waste glass content (G) and age (t) on the concrete compressive strength, flexural strength and ultrasonic pulse velocity. This study also applied a hyperbolic function, an exponential function and a power function in a non-linear regression analysis of multiple variables and established the prediction model that could consider the effect of the water-binder ratio (w/b), waste glass content (G) and age (t) on the concrete compressive strength, flexural strength and ultrasonic pulse velocity.
Compared with the testing results, the statistical analysis shows that the coefficient of determination R2 and the mean absolute percentage error (MAPE) were 0.930.96 and 5.48.4% for the compressive strength, 0.830.89 and 8.912.2% for the flexural strength and 0.870.89 and 1.82.2% for the ultrasonic pulse velocity, respectively. The proposed models are highly accurate in predicting the compressive strength, flexural strength and ultrasonic pulse velocity of waste LCD glass concrete. However, with other ranges of mixture parameters, the predicted models must be further studied.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001929910
|
oai_dc
|
Confining effect of concrete in double-skinned composite tubular columns
|
Confining effect of concrete in double-skinned composite tubular columns
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"원덕희(한국해양과학기술원); 한택희(한국해양과학기술원); 김승준(Marine Research Institute, Samsung Heavy); 이정화(고려대학교); 강영종(고려대학교)"
] |
A double-skinned composite tubular (DSCT) column, which consists of concrete and inner and outer tubes, was finally developed to overcome the weaknesses of concrete filled tube columns by reducing the self-weight of the column and confining the concrete triaxially. Research pertaining to the stiffness and strength of the column and the confining effect in a DSCT column has been carried out. However, detailed studies on the confining stress, especially the internal confining stress in a DSCT column, have not been carried out. Internal and external confining stresses should be evaluated to determine the effective confining stress in a DSCT column. In this paper, the confining stresses of concrete before and after insertion of an inner tube were studied using finite element analysis. The relationship between the internal or external confining stresses and the theoretical confining stress was investigated by parametric studies. New modified formulae for the yield and buckling failure conditions based on the formulae suggested by former researchers were proposed. Through analytical studies, the modified formulae were verified to be effective for economic and reasonable design of the inner tubes in a DSCT column under the same confining stress.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001929902
|
oai_dc
|
Study on fracture behavior of polypropylene fiber reinforced concrete with bending beam test and digital speckle method
|
Study on fracture behavior of polypropylene fiber reinforced concrete with bending beam test and digital speckle method
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Peng Cao(Tsinghua University); Decheng Feng(Harbin Institute of Tehcnology); Changjun Zhou(Tsinghua University); Wenxin Zuo(University of Birmingham)"
] |
Portland cement concrete, which has higher strength and stiffness than asphalt concrete, has been widely applied on pavements. However, the brittle fracture characteristic of cement concrete restricts its application in highway pavement construction. Since the polypropylene fiber can improve the fracture toughness of cement concrete, Polypropylene Fiber-Reinforced Concrete (PFRC) is attracting more and more attention in civil engineering. In order to study the effect of polypropylene fiber on the generation and evolution process of the local deformation band in concrete, a series of three-point bending tests were performed using the new technology of the digital speckle correlation method for FRC notched beams with different volumetric contents of polypropylene fiber. The modified Double-K model was utilized for the first time to calculate the stress intensity factors of instability and crack initiation of fiber-reinforced concrete beams. The results indicate that the polypropylene fiber can enhance the fracture toughness. Based on the modified Double-K fracture theory, the maximum fracture energy of concrete with 3.2% fiber (in volume) is 47 times higher than the plain concrete. No effort of fiber content on the strength of the concrete was found. Meanwhile to balance the strength and resistant fracture toughness, concrete with 1.6% fiber is recommended to be applied in pavement construction.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001929905
|
oai_dc
|
Prediction of acceleration and impact force values of a reinforced concrete slab
|
Prediction of acceleration and impact force values of a reinforced concrete slab
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"R. Tuğrul Erdem(Celal Bayar University)"
] |
Concrete which is a composite material is frequently used in construction works. Properties and behavior of concrete are significant under the effect of different loading cases. Impact loading which is a sudden dynamic one may have destructive effects on structures. Testing apparatuses are designed to investigate the impact effect on test members. Artificial Neural Network (ANN) is a computational model that is inspired by the structure or functional aspects of biological neural networks. It can be defined as an emulation of biological neural system. In this study, impact parameters as acceleration and impact force values of a reinforced concrete slab are obtained by using a testing apparatus and essential test devices. Afterwards, ANN analysis which is used to model different physical dynamic processes depending on several variables is performed in the numerical part of the study. Finally, test and predicted results are compared and it’s seen that ANN analysis is an alternative way to predict the results successfully.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001929908
|
oai_dc
|
Construction stages analyses using time dependent material properties of concrete arch dams
|
Construction stages analyses using time dependent material properties of concrete arch dams
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Barış Sevim(Yildiz Technical University); Ahmet C. Altunışık(Karadeniz Technical University); Alemdar Bayraktar(Karadeniz Technical University)"
] |
This paper presents the effects of the construction stages using time dependent material properties on the structural behaviour of concrete arch dams. For this purpose, a double curvature Type-5 arch dam suggested in ‘‘Arch Dams’’ symposium in England in 1968 is selected as a numerical example. Finite element models of Type-5 arch dam are modelled using SAP2000 program. Geometric nonlinearity is taken into consideration in the construction stage analysis using P-Delta plus large displacement criterion. In addition, the time dependent material strength variations and geometric variations are included in the analysis. Elasticity modulus, creep and shrinkage are computed for different stages of the construction process. In the construction stage analyses, a total of 64 construction stages are included. Each stage has generally 6000 m3 concrete volume. Total duration is taken into account as 1280 days. Maximum total step and maximum iteration for each step are selected as 200 and 50, respectively. The structural behaviour of the arch dam at different construction stages has been examined. Two different finite element analyses cases are performed. In the first case, construction stages using time dependent material properties are considered. In the second case, only linear static analysis (not considered construction stages) is taken into account. Variation of the displacements and stresses are obtained from the both analyses. It is highlighted that construction stage analysis using time dependent material strength variations and geometric variations has an important effect on the structural behaviour of arch dams. The maximum longitudinal, transverse and vertical displacements obtained from construction stages and static analyses are 1.35 mm and 0 mm; -8.44 and 6.68 mm; -4.00 and -9.90 mm, respectively. In addition, vertical displacements increase from the base to crest of the dam for both analyses. The maximum S11, S22 and S33 stresses are obtained as 1.60MPa and 2.84MPa; 1.39MPa and 2.43MPa; 0.60MPa and 0.50MPa, respectively. The differences between maximum longitudinal, transverse, and vertical stresses obtained from construction stage and static analyses are 78%, 75%, and %17, respectively. On the other hand, there is averagely 12% difference between minimum stresses for all three directions.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002018468
|
oai_dc
|
Probabilistic models for curvature ductility and moment redistribution of RC beams
|
Probabilistic models for curvature ductility and moment redistribution of RC beams
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hassan Baji(The University of Queensland); Hamid Reza Ronagh(The University of Queensland)"
] |
It is generally accepted that, in the interest of safety, it is essential to provide a minimum level of flexural ductility, which will allow energy dissipation and moment redistribution as required. If one wishes to be uniformly conservative across all of the design variables, curvature ductility and moment redistribution factor should be calculated using a probabilistic method, as is the case for other design parameters in reinforced concrete mechanics. In this study, simple expressions are derived for the evaluation of curvature ductility and moment redistribution factor, based on the concept of demand and capacity rotation. Probabilistic models are then derived for both the curvature ductility and the moment redistribution factor, by means of central limit theorem and through taking advantage of the specific behaviour of moment redistribution factor as a function of curvature ductility and plastic hinge length. The Monte Carlo Simulation (MCS) method is used to check and verify the results of the proposed method. Although some minor simplifications are made in the proposed method, there is a very good agreement between the MCS and the proposed method. The proposed method could be used in any future probabilistic evaluation of curvature ductility and moment redistribution factors.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002018474
|
oai_dc
|
A graphical user interface for stand-alone and mixed-type modelling of reinforced concrete structures
|
A graphical user interface for stand-alone and mixed-type modelling of reinforced concrete structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Vahid Sadeghian(University of Toronto); Frank Vecchio(University of Toronto)"
] |
FormWorks-Plus is a generalized public domain user-friendly preprocessor developed to facilitate the process of creating finite element models for structural analysis programs. The lack of a graphical user interface in most academic analysis programs forces users to input the structural model information into the standard text files, which is a time-consuming and error-prone process. FormWorks-Plus enables engineers to conveniently set up the finite element model in a graphical environment, eliminating the problems associated with conventional input text files and improving the user’s perception of the application. In this paper, a brief overview of the FormWorks-Plus structure is presented, followed by a detailed explanation of the main features of the program. In addition, demonstration is made of the application of FormWorks-Plus in combination with VecTor programs, advanced nonlinear analysis tools for reinforced concrete structures. Finally, aspects relating to the modelling and analysis of three case studies are discussed: a reinforced concrete beam-column joint, a steel-concrete composite shear wall, and a SFRC shear panel. The unique mixed-type frame-membrane modelling procedure implemented in FormWorks-Plus can address the limitations associated with most frame type analyses.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002018473
|
oai_dc
|
Mechanical properties of recycled fine glass aggregate concrete under uniaxial loading
|
Mechanical properties of recycled fine glass aggregate concrete under uniaxial loading
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jiong-Feng Liang(East China Institute of Technology); Ze-Ping Yang(East China Institute of Technology); Ping-Hua Yi(East China Institute of Technology); Jian-Bao Wang(East China Institute of Technology)"
] |
This paper reports the results of an experimental study on the compressive strength and the stress-strain curve (SSC) of recycled fine glass aggregate concrete with different replacement percentages of recycled fine glass aggregate. The results show that the recycled fine glass aggregate contents have significant impact on the workability, compressive strength, the elastic modulus, the peak and the ultimate strains of recycled fine glass aggregate concrete. Analytical expressions for the stress–strain relationship of recycled fine glass aggregate concrete are given, which can satisfactorily describe the effect of the recycled fine glass aggregate on the SSC.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002018476
|
oai_dc
|
A general tangent operator applied to concrete using a multi-surface plasticity model
|
A general tangent operator applied to concrete using a multi-surface plasticity model
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ana Beatriz C.G. Silva(Federal University of Rio de Janeiro); Jose Claudio F. Telles(Federal University of Rio de Janeiro); Eduardo M.R. Fairbairn(Federal University of Rio de Janeiro); Fernando Luiz B. Ribeiro(Federal University of Rio de Janeiro)"
] |
The present paper aims at developing a method to accommodate multi-surface concrete plasticity from the point of view of a consistency concept applied to general tangent operators. The idea is based on a Taylor series expansion of the actual effective stress at the stress point corresponding to the previous accumulated true stresses plus the current increment values, initially taken to be elastic. The proposed algorithm can be generalized for any multi-surface criteria combination and has been tested here for typical cement-based materials. A few examples of application are presented to demonstrate the effectiveness of the multi-surface technique as used to a combination of Rankine and Drucker-Prager yield criteria.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002018469
|
oai_dc
|
Strength criterion of plain recycled aggregate concrete under biaxial compression
|
Strength criterion of plain recycled aggregate concrete under biaxial compression
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Zhen-Jun He(North China University of Technology); Gan-Wen Liu(North China University of Technology); Wan-Lin Cao(Beijing University of Technology); Chang-Yang Zhou(North China University of Technology); Zhang Jia-Xing(North China University of Technology)"
] |
This paper presents results of biaxial compressive tests and strength criterion on two replacement percentages of recycled coarse aggregate (RPRCA) by mass for plain structural recycled aggregate concrete (RAC) at all kinds of stress ratios. The failure mode characteristic of specimens and the direction of the cracks were observed and described. The two principally static strengths in the corresponding stress state were measured. The influence of the stress ratios on the biaxial strengths of RAC was also analyzed. The experimental results showed that the ratios of the biaxial compressive strength 3f to the corresponding uniaxial compressive strength c for the two RAC are higher than that of the conventional concrete (CC), and dependent on the replacement percentages of recycled coarse aggregate, stress states and stress ratios; however, the differences of tensile-compressive ratios for the two RAC and CC are smaller. On this basis, a new failure criterion with the stress ratios is proposed for plain RAC under biaxial compressive stress states. It provides the experimental and theoretical foundations for strength analysis of RAC structures subject to complex loads.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002018471
|
oai_dc
|
Analysis of rectangular hybrid steel-GFRP reinforced concrete beam columns
|
Analysis of rectangular hybrid steel-GFRP reinforced concrete beam columns
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Rafic G. El-Helou(Syracuse University); Riyad S. Aboutaha(Syracuse University)"
] |
In this study, nominal moment-axial load interaction diagrams, moment-curvature relationships, and ductility of rectangular hybrid beam-column concrete sections are analyzed using the modified Hognestad concrete model. The hybrid columns are primarily reinforced with steel bars with additional Glass Fiber Reinforced Polymer (GFRP) control bars. Parameters investigated include amount, pattern, location, and material properties of concrete, steel, and GFRP. The study was implemented using a user defined comprehensive MATLAB® simulation model to find an efficient hybrid section design maximizing strength and ductility. Generating lower bond stresses than steel bars at the concrete interface, auxiliary GFRP bars minimize damage in the concrete core of beam-column sections. Their usage prevents excessive yielding of the core longitudinal bars during frequent moderate cyclic deformations, which leads to significant damage in the foundations of bridges or beam-column spliced sections where repair is difficult and expensive. Analytical results from this study shows that hybrid steel-GFRP composite concrete sections where GFRP is used as auxiliary bars show adequate ductility with a significant increase in strength. Results also compare different design parameters reaching a number of design recommendations for the proposed hybrid section.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002018472
|
oai_dc
|
Expansion behavior of low-strength steel slag mortar during high-temperature catalysis
|
Expansion behavior of low-strength steel slag mortar during high-temperature catalysis
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Wen-Ten Kuo(National Kaohsiung University of Applied); Chun-Ya Shu(National Kaohsiung University of Applied Sciences)"
] |
This study established the standard recommended values and expansion fracture threshold values for the content of steel slag in controlled low-strength materials (CLSM) to ensure the appropriate use of steel slag aggregates and the prevention of abnormal expansion. The steel slags used in this study included basic oxygen furnace (BOF) slag and desulfurization slag (DS), which replaced 5-50% of natural river sand by weight in cement mixtures. The steel slag mortars were tested by high-temperature (100°C) curing for 96 h and autoclave expansion. The results showed that the effects of the steel slag content varied based on the free lime (f-CaO) content. No more than 30% of the natural river sand should be replaced with steel slag to avoid fracture failure. The expansion fracture threshold value was 0.10%, above which there was a risk of potential failure. Based on the scanning electron microscopy (SEM) analysis, the high-temperature catalysis resulted in the immediate extrusion of peripheral hydration products from the calcium hydroxide crystals, leading to a local stress concentration and, eventually, deformation and cracking.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002018475
|
oai_dc
|
Implementation of bond-slip effects on behaviour of slabs in structures
|
Implementation of bond-slip effects on behaviour of slabs in structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S.S. Mousavi(Babol Noshirvani University of Technology); M. Dehestani(Babol Noshirvani University of Technology)"
] |
Employing discrete elements for considering bond-slip effects in reinforced concrete structures is very time consuming. In this study, a new modified embedded element method is used to consider the bond-slip phenomenon in structural behavior of reinforced concrete structures. A comprehensive parametric study of RC slabs is performed to determine influence of different variables on structural behavior. The parametric study includes a set of simple models accompanied with complex models such as multi-storey buildings. The procedure includes the decrease in the effective stiffness of steel bar in the layered model. Validation of the proposed model with existing experimental results demonstrates that the model is capable of considering the bond-slip effects in embedded elements. Results demonstrate the significant effect of bond-slip on total behavior of structural members. Concrete characteristic strengths, steel yield stress, bar diameter, concrete coverage and reinforcement ratios are the parameters considered in the parametric study. Results revealed that the overall behavior of slab is significantly affected by bar diameter compared with other parameters. Variation of steel yield stress has insignificant impact in static response of RC slabs; however, its effect in cyclic behavior is important.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002018470
|
oai_dc
|
Instantaneous and time-dependent flexural cracking models of reinforced self-compacting concrete slabs with and without fibres
|
Instantaneous and time-dependent flexural cracking models of reinforced self-compacting concrete slabs with and without fibres
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Farhad Aslani(University of New South Wales); Shami Nejadi(University of Technology Sydney); Bijan Samali(University of Western Sydney)"
] |
Self-compacting concrete (SCC) can be placed and compacted under its own weight with little or no compaction. It is cohesive enough to be handled without segregation or bleeding. Modifications in the mix design of SCC may significantly influence the material’s mechanical properties. Therefore, it is vital to investigate whether all the assumed hypotheses about conventional concrete (CC) are also valid for SCC structures. The aim in this paper is to develop analytical models for flexural cracking that describe in appropriate detail the observed cracking behaviour of the reinforced concrete flexural one way slabs tested. The crack width and crack spacing calculation procedures outlined in five international codes, namely Eurocode 2 (1991), CEB-FIP (1990), ACI318-99 (1999), Eurocode 2 (2004), and fib-Model Code (2010), are presented and crack widths and crack spacing are accordingly calculated. Then, the results are compared with the proposed analytical models and the measured experimental values, and discussed in detail.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001897312
|
oai_dc
|
New analytical model for the hoop contribution to the shear capacity of circular reinforced concrete columns
|
New analytical model for the hoop contribution to the shear capacity of circular reinforced concrete columns
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Francesco Trentadue(Technical University of Bari); Giuseppe Quaranta(Sapienza University of Rome); Rita Greco(Technical University of Bari); Giuseppe Carlo Marano(Technical University of Bari)"
] |
The paper is concerned with the analytical description of a resistance mechanism, not considered in previous models, by which the hoops contribute to the shear capacity of RC columns with circular cross sections. The difference from previous approaches consists in observing that, because of deformation, the hoops change their original shape and, as a consequence, their slope does not match anymore the original one in the neighborhood of a crack. The model involves two parameters only, namely the crack inclination and the hoop strain in the neighborhood of a crack. A closed-form analytical formulation to correlate the average value of the crack width and the hoop strain is also provided. Results obtained using the proposed model have been compared with experimental data, and a satisfactory agreement is found.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001897317
|
oai_dc
|
Vibration based damage detection in a scaled reinforced concrete building by FE model updating
|
Vibration based damage detection in a scaled reinforced concrete building by FE model updating
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Temel Türker(Department of Civil Engineering, Karaden); Alemdar Bayraktar(Department of Civil Engineering, Karaden)"
] |
The traditional destructive tests in damage detection require high cost, long consuming time, repairing of damaged members, etc. In addition to these, powerful equipments with advanced technology have motivated development of global vibration based damage detection methods. These methods base on observation of the changes in the structural dynamic properties and updating finite element models. The existence, location, severity and effect on the structural behavior of the damages can be identified by using these methods. The main idea in these methods is to minimize the differences between analytical and experimental natural frequencies. In this study, an application of damage detection using model updating method was presented on a one storey reinforced concrete (RC) building model. The model was designed to be 1/2 scale of a real building. The measurements on the model were performed by using ten uni-axial seismic accelerometers which were placed to the floor level. The presented damage identification procedure mainly consists of five steps: initial finite element modeling, testing of the undamaged model, finite element model calibration, testing of the damaged model, and damage detection with model updating. The elasticity modulus was selected as variable parameter for model calibration, while the inertia moment of section was selected for model updating. The first three modes were taken into consideration. The possible damaged members were estimated by considering the change ratio in the inertia moment. It was concluded that the finite element model calibration was required for structures to later evaluations such as damage, fatigue, etc. The presented model updating based procedure was very effective and useful for RC structures in the damage identification.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001897310
|
oai_dc
|
A method for the non-linear and failure load analysis of reinforced concrete frames
|
A method for the non-linear and failure load analysis of reinforced concrete frames
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Turgay Cosgun1(Istanbul University); Baris Sayin(Istanbul University)"
] |
Modern trend in structural design is to use smaller elements in order to ensure several purposes such as economy, functionality and aesthetic in appearance. However, because of decreasing rigidity of the structural elements, the system displacements increases and displacements become an important subject in this kind of structures takes into account both geometrical changes and the carrying capacity of the material after linear-elastic boundary. In this study, a method is proposed to calculate the failure loads and to analyse the reinforced concrete space frame systems. The numerical examples gathered from the literature survey are solved with this method utilising the prepared computer program and the comparable results are presented. The results show that the method is sufficiently accurate.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001897289
|
oai_dc
|
Fiber reinforced concrete L-beams under combined loading
|
Fiber reinforced concrete L-beams under combined loading
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Omer Farouk Ibraheem(University Sains Malaysia (USM)); B.H. Abu Bakar(University Sains Malaysia (USM)); I. Joharib(University Sains Malaysia (USM))"
] |
The addition of steel fibers in concrete mixture is recognized as a non-conventional mass reinforcement scheme that improves the torsional, flexural, and shear behavior of structural members. However, the analysis of fiber reinforcedconcrete beams under combined torsion, bending, and shear is limited because of the complicated nature of the problem. Therefore, nonlinear 3D finite element analysis was conducted using the “ANSYS CivilFEM” program to investigate the behavior of fiber reinforced concrete L-beams. These beams were tested at different reinforcement schemes and loading conditions. The reinforcement case parameters were set as follows: reinforced with longitudinal reinforcement only and reinforced with steel bars and stirrups. All beams were tested under two different combined loading conditions, namely, torsion-to-shear ratio (T/V) = 545 mm (high eccentricity) and T/V = 145 mm (low eccentricity). Eight intermediate L-beams were constructed and tested in a laboratory under combined torsion, bending, and shear to validate the finite element model. Comparisons with the experimental data reveal that the program can accurately predict the behavior of L-beams under different reinforcement cases and combined loading ratios. The ANSYS model accurately predicted the loads and deformations for various types of reinforcements in L-beams and captured the concrete strains of these beams.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001897308
|
oai_dc
|
New strut-and-tie-models for shear strength prediction and design of RC deep beams
|
New strut-and-tie-models for shear strength prediction and design of RC deep beams
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Panatchai Chetchotisak(Khon Kaen University); Jaruek Teerawong(Khon Kaen University); Sukit Yindeesuk(Ministry of Transport); 송준호(서울대학교)"
] |
Reinforced concrete deep beams are structural beams with low shear span-to-depth ratio, and hence in which the strain distribution is significantly nonlinear and the conventional beam theory is not applicable. A strut-and-tie model is considered one of the most rational and simplest methods available for shear strength prediction and design of deep beams. The strut-and-tie model approach describes the shear failure of a deep beam using diagonal strut and truss mechanism: The diagonal strut mechanism represents compression stress fields that develop in the concrete web between diagonal cracks of the concrete while the truss mechanism accounts for the contributions of the horizontal and vertical web reinforcements. Based on a database of 406 experimental observations, this paper proposes a new strut-and-tie-model for accurate prediction of shear strength of reinforced concrete deep beams, and further improves the model by correcting the bias and quantifying the scatter using a Bayesian parameter estimation method. Seven existing deterministic models from design codes and the literature are compared with the proposed method. Finally, a limit-state design formula and the corresponding reduction factor are developed for the proposed strut-andtie model.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001897325
|
oai_dc
|
Cementing failure of the casing-cement-rock interfaces during hydraulic fracturing
|
Cementing failure of the casing-cement-rock interfaces during hydraulic fracturing
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hai Y. Zhu(Southwest Petroleum University); Jin G. Deng(China University of Petroleum); Jun Zhao(Oilfield Chemicals R & D Institute); Hu Zhao(Oilfield Chemicals R & D Institute); Hai L. Liu(China University of Petroleum); Teng Wang(Southwest Petroleum University)"
] |
Using the principle of damage mechanics, zero-thickness pore pressure cohesive elements(PPCE) are used to simulate the casing-cement interface (CCI) and cement-rock interface (CRI). The traction-separation law describes the emergence and propagation of the PPCE. Mohr-coulomb criteria determines the elastic and plastic condition of cement sheath and rock. The finite element model (FEM) of delamination fractures emergence and propagation along the casing-cement-rock (CCR) interfaces during hydraulic fracturing is established, and the emergence and propagation of fractures along the wellbore axial and circumferential direction are simulated. Regadless of the perforation angle (the angle between the perforation and the max. horizontal principle stress), mirco-annulus will be produced alonge the wellbore circumferential direction when the cementation strength of the CCI and the CRI is less than the rock tensile strength; the delamination fractures are hard to propagate along the horizontal wellbore axial direction; emergence and propagation of delamination fractures are most likely produced on the shallow formationwhen the in-situ stresses are lower; the failure mode of cement sheath in the deep well is mainly interfaces seperation and body damange caused by cement expansion and contraction, or pressure testing and well shut-in operations.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001936931
|
oai_dc
|
Investigations on the influence of radial confinement in the impact response of concrete
|
Investigations on the influence of radial confinement in the impact response of concrete
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yousef Al-Salloum(King Saud University); Saleh Alsayed(King Saud University); Tarek Almusallam(King Saud University); S.M. Ibrahim(King Saud University); H. Abbas(King Saud University)"
] |
Annular and solid concrete specimens with different aspect ratios and static unconfined compressive strengths were studied for impact loading using SHPB test setup. Numerical simulations in LSDYNA were also carried out and results were validated. The stress-strain curves obtained under dynamic loading were also compared with static compressive tests. The mode of failure of concrete specimen was a typical ductile failure at high strain rates. In general, the dynamic increase factor (DIF) of thin solid specimens was higher than thick samples. In the numerical study, the variation of axial, hydrostatic and radial stresses for solid and annular samples was studied. The core phenomenon due to confinement was observed for solid samples wherein the applied loads were primarily borne by the innermost concrete zone rather than the outer peripheral zone. In the annular samples, especially with large diameter inside hole, the distribution of stresses was relatively uniform along the radial distance. Qualitatively, only a small change in the distribution of stresses for annular samples with different internal diameters studied was observed.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001936928
|
oai_dc
|
Moisture distribution in concrete subjected to rain induced wetting-drying
|
Moisture distribution in concrete subjected to rain induced wetting-drying
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Kaustav Sarkar(Indian Institute of Technology Delhi); Bishwajit Bhattacharjee(Indian Institute of Technology Delhi)"
] |
A rational estimation of moisture distribution in structural concrete is vital for predicting the possible extent and rate of progression of impending degradation processes. The paper proposes a numerical scheme for analysing the evolution of moisture distribution in concrete subjected to wetting-drying exposure caused by intermittent periods of rainfall. The proposed paradigm is based on the stage wise implementation of non-linear finite element (FE) analysis, with each stage representing a distinct phase of a typical wet-dry cycle. The associated boundary conditions have been constituted to realize the influence of various meteorological elements such as rain, wind, relative humidity and temperature on the exposed concrete surface. The reliability of the developed scheme has been demonstrated through its application for the simulation of experimentally recorded moisture profiles reported in published literature. A sensitivity analysis has also been carried out to study the influence of critical material properties on simulated results. The proposed scheme is vital to the service life modelling of concrete structures in tropical climates which largely remain exposed to the action of alternating rains.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001936930
|
oai_dc
|
A numerical procedure for reinforced concrete columns with a focus on stability analysis
|
A numerical procedure for reinforced concrete columns with a focus on stability analysis
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Susana L. Pires(University of Campinas); Maria Cecilia A.T. Silva(University of Campinas)"
] |
The purpose of this paper is to present a numerical procedure to analyse reinforced concrete columns subjected to combined axial loads and bending that rigorously considers nonlinear material and nonlinear geometric characteristics. Column design and stability analysis are simultaneously regarded. A finite element method is used for calculating displacements and the material and geometric nonlinearities are taken into account using an iterative process. A computer program is developed from the proposed numerical procedure, and the efficiency of the program is verified against available experimental data. The model applies to constant rectangular cross sectional columns with symmetric reinforcement distribution.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001936936
|
oai_dc
|
Experimental study and numerical investigation of behavior of RC beams strengthened with steel reinforced grout
|
Experimental study and numerical investigation of behavior of RC beams strengthened with steel reinforced grout
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Francesco Bencardino(University of Calabria); Antonio Condello(University of Calabria)"
] |
The purpose of this study is to evaluate the behavior and the strength of SRG (Steel Reinforced Grout) externally strengthened Reinforced Concrete (RC) beams by using a nonlinear numerical analysis. The numerical simulation was carried out by using a three-dimensional (3D) finite element model. An interface element with a suitable damage model was used to model the connection between concrete surface and SRG reinforcing layer. The reliability of the finite element 3D-model was checked using experimental data obtained on a set of three RC beams.
The parameters taken into consideration were the external configuration, with or without U-end anchorages, the concrete strength, the amount of internal tensile steel reinforcement.
Conclusions were made concerning the strength and the ductility of the strengthened beams by varying the parameters and on the effectiveness of the SRG reinforcing system applied with two types of external strengthening configuration.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001936940
|
oai_dc
|
Finite element model updating effect on the structural behavior of long span concrete highway bridges
|
Finite element model updating effect on the structural behavior of long span concrete highway bridges
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A.C. Altunisik(Karadeniz Technical University); A. Bayraktar(Karadeniz Technical University)"
] |
In this paper, it is aimed to determine the finite element model updating effects on the structural behavior of long span concrete highway bridges. Birecik Highway Bridge located on the 81stkm of Şanlıurfa-Gaziantep state highway over Fırat River in Turkey is selected as a case study. The bridge consist of fourteen spans, each of span has a nearly 26m. The total bridge length is 380m and width of bridge is 10m. Firstly, the analytical dynamic characteristics such as natural frequencies and mode shapes are attained from finite element analyses using SAP2000 program. After, experimental dynamic characteristics are specified from field investigations using Operational Modal Analysis method. Enhanced Frequency Domain Decomposition method in the frequency domain is used to extract the dynamic characteristics such as natural frequencies, mode shapes and damping ratios. Analytically and experimentally identified dynamic characteristics are compared with each other and finite element model of the bridge is updated to reduce the differences by changing of some uncertain parameters such as section properties, damages, boundary conditions and material properties. At the end of the study, structural performance of the highway bridge is determined under dead load, live load, and dynamic loads before and after model updating to specify the updating effect. Displacements, internal forces and stresses are used as comparison parameters. From the study, it is seen that the ambient vibration measurements are enough to identify the most significant modes of long span highway bridges. Maximum differences between the natural frequencies are reduced averagely from %46.7 to %2.39 by model updating. A good harmony is found between mode shapes after finite element model updating. It is demonstrated that finite element model updating has an important effect on the structural performance of the arch type long span highway bridge. Maximum displacements, shear forces, bending moments and compressive stresses are reduced %28.6, %21.0, %19.22, and %33.3-20.0, respectively.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001936934
|
oai_dc
|
A nonlinear model for ultimate analysis and design of reinforced concrete structures
|
A nonlinear model for ultimate analysis and design of reinforced concrete structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Konstantinos Morfidis(Institute of Engineering Seismology); Panos D. Kiousis(Colorado School of Mines); Hariton Xenidis(Aristotle University of Thessaloniki)"
] |
This paper presents a theoretical and computational approach to solve inelastic structures subjected to overloads. Current practice in structural design is based on elastic analysis followed by limit strength design. Whereas this approach typically results in safe strength design, it does not always guarantee satisfactory performance at the service level because the internal stiffness distribution of the structure changes from the service to the ultimate strength state. A significant variation of relative stiffnesses between the two states may result in unwanted cracking at the service level with expensive repairs, while, under certain circumstances, early failure may occur due to unexpected internal moment reversals. To address these concerns, a new inelastic model is presented here that is based on the nonlinear material response and the interaction relation between axial forces and bending moments of a beam-column element. The model is simple, reasonably accurate, and computationally efficient. It is easy to implement in standard structural analysis codes, and avoids the complexities of expensive alternative analyses based on 2D and 3D finite-element computations using solid elements.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001936938
|
oai_dc
|
Advanced performance evaluation system for existing concrete bridges
|
Advanced performance evaluation system for existing concrete bridges
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ayaho Miyamoto(Yamaguchi University); Hisao Emoto(Yamaguchi University); Hiroyoshi Asano(2Ube Industries Consultant Co)"
] |
The management of existing concrete bridges has become a major social concern in many developed countries due to the large number of bridges exhibiting signs of significant deterioration. This problem has increased the demand for effective maintenance and renewal planning. In order to implement an appropriate management procedure for a structure, a wide array of corrective strategies must be evaluated with respect to not only the condition state of each defect but also safety, economy and sustainability. This paper describes a new performance evaluation system for existing concrete bridges. The system evaluates performance based on load carrying capability and durability from the results of a visual inspection and specification data, and describes the necessity of maintenance. It categorizes all girders and slabs as either unsafe, severe deterioration, moderate deterioration, mild deterioration, or safe. The technique employs an expert system with an appropriate knowledge base in the evaluation. A characteristic feature of the system is the use of neural networks to evaluate the performance and facilitate refinement of the knowledge base. The neural network proposed in the present study has the capability to prevent an inference process and knowledge base from becoming a black box. It is very important that the system is capable of detailing how the performance is calculated since the road network represents a huge investment. The effectiveness of the neural network and machine learning method is verified by comparing diagnostic results by bridge experts.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001936942
|
oai_dc
|
Impact of composite materials on performance of reinforced concrete panels
|
Impact of composite materials on performance of reinforced concrete panels
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Sherif A. Mazek(Military Technical College); Ashraf A. Mostafa(Egyptian Engineering Department)"
] |
The use of composite materials to strengthen reinforced concrete (RC) structures against blast terror has great interests from engineering experts in structural retrofitting. The composite materials used in this study are rigid polyurethane foam (RPF) and aluminum foam (ALF). The aim of this study is to use the RPF and the ALF to strengthen the RC panels under blast load. The RC panel is considered to study the RPF and the ALF as structural retrofitting. Field blast test is conducted. The finite element analysis (FEA) is also used to model the RC panel under shock wave. The RC panel performance is studied based on detonating different TNT explosive charges. There is a good agreement between the results obtained by both the field blast test and the proposed numerical model. The composite materials improve the RC panel performance under the blast wave propagation.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002077418
|
oai_dc
|
Reliability-based modeling of punching shear capacity of FRP-reinforced two-way slabs
|
Reliability-based modeling of punching shear capacity of FRP-reinforced two-way slabs
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ahmet Emin Kurtoglu(Zirve University); Abdulkadir Cevik(University of Gaziantep); Hasan M. Albegmprli(Foundation of Technical Education); Mehmet Eren Gulsan(University of Gaziantep); Mahmut Bilgehan(Zirve University)"
] |
This paper deals with the reliability analysis of design formulations derived for predicting the punching shear capacity of FRP-reinforced two-way slabs. Firstly, a new design code formulation was derived by means of gene expression programming. This formulation differs from the existing ones as the slab length (L) was introduced in the equation. Next, the proposed formulation was tested for its generalization capability by a parametric study. Then, the stochastic analyses of derived and existing formulations were performed by Monte Carlo simulation. Finally, the reliability analyses of these equations were carried out based on the results of stochastic analysis and the ultimate state function of ASCE-7 and ACI-318 (2011). The results indicate that the prediction performance of new formulation is significantly higher as compared to available design equations and its reliability index is within acceptable limits.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002077413
|
oai_dc
|
A new precast wall connection subjected to monotonic loading
|
A new precast wall connection subjected to monotonic loading
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ramin Vaghei(University Putra Malaysia); Farzad Hejazi(University Putra Malaysia); Hafez Taheri(University Putra Malaysia); Mohd Saleh Jaafar(University Putra Malaysia); Abang Abdullah Abang Ali(University Putra Malaysia)"
] |
Final construction project cost is significantly determined by construction rate. The Industrialized Building System (IBS) was promoted to enhance the importance of prefabrication technology rather than conventional methods in construction. Ensuring the stability of a building constructed by using IBS is a challenging issue. Accordingly, the connections in a prefabricated building have a basic, natural, and essential role in providing the best continuity among the members of the building. Deficiencies of conventional precast connections were observed when precast buildings experience a large induced load, such as earthquakes and other disasters. Thus, researchers aim to determine the behavior of precast concrete structure with a specific type of connection. To clarify this problem, this study investigates the capacity behavior of precast concrete panel connections for industrial buildings with a new type of precast wall-to-wall connection (i.e., U-shaped steel channel connection). This capacity behavior is compared with the capacity behavior of precast concrete panel connections for industrial buildings that used a common approach (i.e., loop connection), which is subjected to monotonic loading as in-plane and out-of-plane loading by developing a finite element model. The principal stress distribution, deformation of concrete panels and welded wire mesh (BRC) reinforcements, plastic strain trend in the concrete panels and connections, and crack propagations are investigated for the aforementioned connection. Pushover analysis revealed that loop connections have significant defects in terms of strength for in-plane and out-of-plane loads at three translational degrees of freedom compared with the U-shaped steel channel connection.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002077414
|
oai_dc
|
A tension stiffening model for analysis of RC flexural members under service load
|
A tension stiffening model for analysis of RC flexural members under service load
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"K. A. Patel(Indian Institute of Technology Delhi); Sandeep Chaudhary(Malaviya National Institute of Technology Jaipur); A.K. Nagpal(Indian Institute of Technology Delhi)"
] |
Tension-stiffening is the contribution of concrete between the cracks to carry tensile stresses after cracking in Reinforced Concrete (RC) members. In this paper, a tension-stiffening model has been proposed for computationally efficient nonlinear analysis of RC flexural members subjected to service load. The proposed model has been embedded in a typical cracked span length beam element. The element is visualized to consist of at the most five zones (cracked or uncracked). Closed form expressions for flexibility and stiffness coefficients and end displacements have been obtained for the cracked span length beam element. Further, for use in everyday design, a hybrid analytical-numerical procedure has been developed for nonlinear analysis of RC flexural members using the proposed tension-stiffening model. The procedure yields deflections as well as redistributed bending moments.
The proposed model (and developed procedure) has been validated by the comparison with experimental results reported elsewhere and also by comparison with the Finite Element Method (FEM) results. The procedure would lead to drastic reduction in computational time in case of large RC structures.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002077417
|
oai_dc
|
Fiber method analysis of rc beam retrofitted with turnbuckle external post-tensioning
|
Fiber method analysis of rc beam retrofitted with turnbuckle external post-tensioning
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Bernardo A. Lejano(De La Salle University)"
] |
Strengthening as well as correcting unsightly deflections of reinforced concrete (RC) beam may be accomplished by retrofitting. An innovative way to do this retrofitting that is proposed in this study utilizes turnbuckle to apply external post-tensioning. This Turnbuckle External Post-Tensioning (T-EPT) was experimentally proven to improve the serviceability and load carrying capacity of reinforced concrete beams. The T-EPT system comprises a braced steel frame and a turnbuckle mechanism to provide the prestressing force. To further develop the T-EPT, this research aims to develop a numerical scheme to analyze the structural performance of reinforced concrete beams with this kind of retrofitting. The fiber method analysis was used as the numerical scheme. The fiber method is a simplified finite element method that is used in this study to predict the elastic and inelastic behavior of a reinforced concrete beam. With this, parametric study was conducted so that the effective setup of doing the T-EPT retrofitting may be determined. Different T-EPT configurations were investigated and their effectiveness evaluated. Overall, the T-EPT was effective in improving the serviceability condition and load carrying capacity of reinforced concrete beam.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002077429
|
oai_dc
|
Modulus of elasticity of concretes produced with basaltic aggregate
|
Modulus of elasticity of concretes produced with basaltic aggregate
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Lino Maia(University of Porto); Farhad Aslani(The University of New South Wales)"
] |
Basalt is a type of volcanic rocks, grey to black in colour, contains less than 20% quartz, 10% feldspathoid, and at least 65% of the feldspar of its volume. Basalt is considered an igneous rock with fine grains due to the rapid cooling of lava. Basaltic rocks have been widely used as aggregate for various purposes. The study presented in this paper was carried out on basalts that are widespread in the Madeira Island of Portugal and that comprise the major source of local crushed rock aggregates.
This paper discusses an experimental programme that was carried out to study the effects of basaltic aggregate on the compressive strength and modulus of elasticity of concrete. For this purpose, cylinder specimens with 150×300 mm dimensions and prism specimens with 150×150×375 mm dimensions were cast. The experimental programme was carried out with several concrete compositions belonging to strength classes C20/25, C25/30, C30/37, C40/50 and C60/75. The Eurocode 2 indicates the modulus of elasticity should be 20% higher when the aggregates are of basaltic origin, however results showed significant differences and a correction is proposed.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002077432
|
oai_dc
|
Topological optimization procedure considering nonlinear material behavior for reinforced concrete designs
|
Topological optimization procedure considering nonlinear material behavior for reinforced concrete designs
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Marcela Bruna Braga Franca(Universidade Federal de Minas Gerais); Marcelo Greco(Universidade Federal de Minas Gerais); Ricardo Morais Lanes(Universidade Federal de Minas Gerais); Valerio Silva Almeida(Universidade de Sao Paulo)"
] |
The search for new structural systems capable of associating performance and safety requires deeper knowledge regarding the mechanical behavior of structures subject to different loading conditions. The Strut-and-Tie Model is commonly used to structurally designing some reinforced concrete elements and for the regions where geometrical modifications and stress concentrations are observed, called “regions D”. This method allows a better structural behavior representation for strength mechanisms in the concrete structures. Nonetheless, the topological model choice depends on the designer’s experience regarding compatibility between internal flux of loads, geometry and boundary/initial conditions. Thus, there is some difficulty in its applications, once the model conception presents some uncertainty. In this context, the present work aims to apply the Strut-and-Tie Model to nonlinear structural elements together with a topological optimization method. The topological optimization method adopted considers the progressive stiffness reduction of finite elements with low stress values. The analyses performed could help the structural designer to better understand structural conceptions, guaranteeing the safety and the reliability in the solution of complex problems involving structural concrete.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002077425
|
oai_dc
|
The effect of micro pore on the characteristics of crack tip plastic zone in concrete
|
The effect of micro pore on the characteristics of crack tip plastic zone in concrete
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hadi Haeri(Islamic Azad University); V. Sarfarazi(Hamedan University of Technology)"
] |
Concrete is a heterogeneous material containing many weaknesses such as micro-cracks, pores and grain boundaries. The crack growth mechanism and failure behavior of concrete structures depend on the plastic deformation created by these weaknesses. In this article the non-linear finite element method is used to analyze the effect of presence of micro pore near a crack tip on both of the characteristics of crack tip plastic zone (its shape and size) and crack growth properties (such as crack growth length and crack initiation angle) under pure shear loading. The FE Code Franc2D/L is used to carry out these objectives. The effects of the crack-pore configurations and the spacing between micro pore and pre-excising crack tip on the characteristics of crack tip plastic zone and crack growth properties is highlighted. Based on the obtained results, the relative distance between the crack tip and the micro pore affects in very significant way the shape and the size of the crack tip plastic zone. Furthermore, crack growth length and crack initiation angle are mostly influenced by size and shape of plastic zone ahead of crack tip. Also the effects of pore decrease on the crack tip by variation of pore situation from linear to perpendicular configuration. The critical position for a micro pore is in front of the crack tip.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002077415
|
oai_dc
|
Chloride diffusion in concrete associated with single, dual and multi cation types
|
Chloride diffusion in concrete associated with single, dual and multi cation types
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Zijian Song(Hohai University); Linhua Jiang(Hohai University); Ziming Zhang(Hohai University)"
] |
Currently, most of the investigations on chloride diffusion were based on the experiments and simulations concerning single cation type chlorides. Chloride diffusion associated with dual or multi cation types was rarely studied. In this paper, several groups of diffusion experiments are conducted using chloride solutions containing single, dual and multi cation types. A multi-ionic model is also proposed to simulate the chloride diffusion behavior in the experimental tests. The MATLAB software is used to numerically solve the nonlinear PDEs in the multi-ionic model. The experimental and simulated results show that the chloride diffusion behavior associated with different cation types is significantly different. When the single cation type chlorides are adopted, it is found that the bound rates of chloride ions combined with divalent cations are greater than those combined with monovalent cations. When the dual/multi cation type chlorides are adopted, the chloride bound rates increase with the Ca2+/Mg2+ percentage in the source solutions. This evidence indicates that the divalent cations would markedly enhance the chloride binding capacity and reduce the chloride diffusivity. Moreover, on the basis of the analysis, it is also found that the complicated cation types in source solutions are beneficial to reducing the chloride diffusivity.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001957379
|
oai_dc
|
Analyzing the compressive strength of clinker mortars using approximate reasoning approaches – ANN vs MLR
|
Analyzing the compressive strength of clinker mortars using approximate reasoning approaches – ANN vs MLR
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ahmet Beycioğlu(Düzce University); Mehmet Emiroğlu(Düzce University); Yilmaz Kocak(Dumlupinar University); Serkan Subaşı(Düzce University)"
] |
In this paper, Artificial Neural Networks (ANN) and Multiple Linear Regression (MLR) models were discussed to determine the compressive strength of clinker mortars cured for 1, 2, 7 and 28 days. In the experimental stage, 1288 mortar samples were produced from 322 different clinker specimens and compressive strength tests were performed on these samples. Chemical properties of the clinker samples were also determined. In the modeling stage, these experimental results were used to construct the models. In the models tricalcium silicate (C3S), dicalcium silicate (C2S), tricalcium aluminate (C3A), tetracalcium alumina ferrite (C4AF), blaine values, specific gravity and age of samples were used as inputs and the compressive strength of clinker samples was used as output. The approximate reasoning ability of the models compared using some statistical parameters. As a result, ANN has shown satisfying relation with experimental results and suggests an alternative approach to evaluate compressive strength estimation of clinker mortars using related inputs. Furthermore MLR model showed a poor ability to predict.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001957382
|
oai_dc
|
An improved 1D-model for computing the thermal behaviour of concrete dams during operation. Comparison with other approaches
|
An improved 1D-model for computing the thermal behaviour of concrete dams during operation. Comparison with other approaches
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"D. Santillán(Technical University of Madrid); E. Salete(Technical University of Madrid); M.Á. Toled(Technical University of Madrid); A. Granados(Technical University of Madrid)"
] |
Thermal effects are significant loads for assessing concrete dam behaviour during operation. A new methodology to estimate thermal loads on concrete dams taking into account processes which were previously unconsidered, such as: the evaporative cooling, the night radiating cooling or the shades, has been recently reported. The application of this novel approach in combination with a three-dimensional finite element method to solve the heat diffusion equation led to a precise characterization of the thermal field inside the dam. However, that approach may be computationally expensive. This paper proposes the use of a new one-dimensional model based on an explicit finite difference scheme which is improved by means of the reported methodology for computing the heat fluxes through the dam faces.
The improved model has been applied to a case study where observations from 21 concrete thermometers and data of climatic variables were available. The results are compared with those from: (a) the original one-dimensional finite difference model, (b) the Stucky-Derron classical one-dimensional analytical solution, and (c) a three-dimensional finite element method. The results of the improved model match well with the observed temperatures, in addition they are similar to those obtained with (c) except in the vicinity of the abutments, although this later is a considerably more complex methodology. The improved model have a better performance than the models (a) and (b), whose results present larger error and bias when compared with the recorded data.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001957384
|
oai_dc
|
Modelling of chloride diffusion in saturated concrete
|
Modelling of chloride diffusion in saturated concrete
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Wen-Hu Tsao(China University of Science and Technolo); Nai-Ming Huang(China University of Science and Technolo); Ming-Te Liang(National Taiwan Ocean University)"
] |
The process of chloride ingress in saturated concrete was presented by a previous study that used a mathematical model for the same as that concrete. This model is to be studied chloride ion diffusion which is considered as a chemical phenomenon and is to be represented the chloride diffusion process to be a nonlinear partial differential equation (PDE). In this paper, this nonlinear PDE is solved by the Kirchhoff transformation to render into a linear PDE. This linear PDE associated with initial and boundary conditions is also solved by the Laplace transformation to obtain an analytical solution. To verify the serviceability and reliability of this proposed method, the practical application should be supplied. The input parameters were cited from the previous study. The free chloride concentration profiles obtained by the analytical solution of mathematical model for saturated concretes after 24 and 120 hrs of exposure were compared with the previous study. The predicted results obtained from proposed method have a tendency with experimental results obtained by the previous study and trend toward numerical results approximated by finite difference technique.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001957375
|
oai_dc
|
A 3D analytical model for the probabilistic characteristics of self-healing model for concrete using spherical microcapsule
|
A 3D analytical model for the probabilistic characteristics of self-healing model for concrete using spherical microcapsule
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"He-hua Zhu(Tongji University); Shuai Zhou(Tongji University); Zhi-guo Yan(Tongji University); Woody Ju(University of California); Qing Chen(Tongji University,)"
] |
In general, cracks significantly deteriorate the in-situ performance of concrete members and structures, especially in urban metro tunnels that have been embedded in saturated soft soils. The microcapsule self-healing method is a newly developed healing method for repairing cracked concrete. To investigate the optimal microcapsule parameters that will have the best healing effect in concrete, a 3D analytical probability healing model is proposed; it is based on the microcapsule self-healing method’s healing mechanism, and its purpose is to predict the healing efficiency and healing probability of given cracks. The proposed model comprehensively considers the radius and the volume fraction of microcapsules, the expected healing efficiency, the parameters of cracks, the broken ratio and the healing probability. Furthermore, a simplified probability healing model is proposed to facilitate the calculation. Then, a Monte Carlo test is conducted to verify the proposed 3D analytical probability healing model. Finally, the influences of microcapsules’ parameters on the healing efficiency and the healing probability of the microcapsule self-healing method are examined in light of the proposed probability model.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001957376
|
oai_dc
|
Data-driven SIRMs-connected FIS for prediction of external tendon stress
|
Data-driven SIRMs-connected FIS for prediction of external tendon stress
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"See Hung Lau(Universiti Malaysia Sarawak); Chee Khoon Ng(Universiti Malaysia Sarawak); Kai Meng Tay(Universiti Malaysia Sarawak)"
] |
This paper presents a novel harmony search (HS)-based data-driven single input rule modules (SIRMs)-connected fuzzy inference system (FIS) for the prediction of stress in externally prestressed tendon. The proposed method attempts to extract causal relationship of a system from an input-output pairs of data even without knowing the complete physical knowledge of the system. The monotonicity property is then exploited as an additional qualitative information to obtain a meaningful SIRMs-connected FIS model. This method is then validated using results from test data of the literature. Several parameters, such as initial tendon depth to beam ratio; deviators spacing to the initial tendon depth ratio; and distance of a concentrated load from the nearest support to the effective beam span are considered. A computer simulation for estimating the stress increase in externally prestressed tendon, Δfps, is then reported. The contributions of this paper is two folds; (i) it contributes towards a new monotonicity-preserving data-driven FIS model in fuzzy modeling and (ii) it provides a novel solution for estimating the Δfps even without a complete physical knowledge of unbonded tendons.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001957372
|
oai_dc
|
Seismic rehabilitation of substandard RC columns with partially deteriorated concrete using CFRP composites
|
Seismic rehabilitation of substandard RC columns with partially deteriorated concrete using CFRP composites
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Dongxu Hou(Dalian University of Technology); Zhimin Wu(Dalian University of Technology); Jianjun Zheng(Zhejiang University of Technology); Yao Cui(Dalian University of Technology)"
] |
Many existing reinforced concrete (RC) columns in structures tend to become substandard RC ones due to updated standards or environmental changes. These substandard columns may alter the behaviors of the whole structure and therefore are in urgent need of seismic retrofitting. Owing to their superior advantages, carbon fiber reinforced polymer (CFRP) composites are widely used to retrofit RC columns. The applications mainly focus on various substandard RC columns, but few deals with substandard columns with deteriorated concrete, especially damaged by earthquake. The purpose of this paper is to investigate the seismic behaviors of CFRP reinforced partially deteriorated RC columns and to evaluate the effect of CFRP sheets on them. Six flexure-dominant columns were tested under a constant axial load and transverse cyclic displacements. It is found that the seismic behaviors of partially deteriorated columns can be recovered by wrapping CFRP sheets on them. Numerical analysis is then conducted using finite element methods and verified with experimental results. The effects of the axial load ratio, the ratio of the thickness of CFRP sheet to the column diameter, and the slenderness ratio on the seismic behaviors of CFRP reinforced RC columns are evaluated. Finally, a method is proposed to determine the required thickness of CFRP sheet.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001957378
|
oai_dc
|
Repaired concrete columns with fiber reinforced thixotropic mortar: experimental & FEA approach
|
Repaired concrete columns with fiber reinforced thixotropic mortar: experimental & FEA approach
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Dimitra V. Achillopoulou(Democritus University of Thrace); Konstantinia C. Arvanitidou(Democritus University of Thrace); Athanasios I. Karabinis(Democritus University of Thrace)"
] |
Following previous studies, the current paper describes the results of an experimental program concerning the repair of reinforced concrete columns by thixotropic pseudo plastic mortar, preformed to analyze and quantify the influence of initial construction damage to the behavior of the repaired element. Five columns (section scale 1:2) were designed according to the minimum requirements of reinforcement of ductility orientated codes’ design with variables the percentages of initial construction damages. All were tested in axial compression with repeated cycles up to failure. For comparison reasons, another one of the same characteristics, yet healthy, was constructed and tested as a reference specimen. A numerical study (Finite Element Analysis) was conducted for further investigation of the behavior of the thixotropic mortar as repair material. The results indicate that: a) surpassing a specific amount of damage, columns even suitably repaired present lower strain capacity, b) finite element analysis present the same way of deboning of the repaired material taking into consideration the buckling of the reinforcement bars.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART001957373
|
oai_dc
|
High-strength concrete deep beams with web openings strengthened by carbon fiber reinforced plastics
|
High-strength concrete deep beams with web openings strengthened by carbon fiber reinforced plastics
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Wen-Yao Lu(China University of Technology); Hsin-Wan Yu(China University of Technology); Chun-Liang Chen(China University of Technology); Shen-Lung Liu(China University of Technology); Ting-Chou Che(China University of Technology)"
] |
The objective of this study is to examine the effect of carbon fiber reinforced polymer (CFRP) on the shear strengths of deep beams with web openings. A total of 18 high-strength concrete deep beams with web openings were tested. Twelve were externally wrapped with four layers of CFRP, six of them strengthened in the horizontal direction and the others in the vertical direction. The parameters of the configuration of CFRP, the sizes of the openings and the locations of the openings were covered in this study. The test results indicates the shear strengths of deep beams with openings sized 60×40 mm were about 16% higher than that with openings sized 68×68 mm. For deep beams with openings sized 60×40 mm, the lower the locations of openings the higher the shear strengths were. The test results also indicate the shear strengths of deep beams with web openings strengthened by CFRP wrapped in the vertical direction can be enhanced by about 10%. However, the shear strengths of deep beams with web openings strengthened by CFRP wrapped in the horizontal direction can only be enhanced by about 6%. The shear strengths of deep beam, with different size and location of web openings and strengthened by different configuration of CFRP can be reasonably predicted by the empirical formulas of Kong and Sharp.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002089598
|
oai_dc
|
Transverse reinforcement for confinement at plastic hinge of circular composite hollow RC columns
|
Transverse reinforcement for confinement at plastic hinge of circular composite hollow RC columns
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"원덕희(한국해양과학기술원); 한택희(한국해양과학기술원); 김승준(대전대학교); 박우선(한국해양과학기술원); 강영종(고려대학교)"
] |
Confined transverse reinforcement was arranged in a plastic hinge region to resist the lateral load that increased the lateral confinement effect in the bridge substructure. Columns increased the seismic performance through securing stiffness and ductility. The calculation method of transverse reinforcements at plastic hinges is reported in the AASHTO-LRFD specification. This specification was only proposed for solid reinforced concrete (RC) columns. Therefore, if this specification is applied for another column as composite column besides the solid RC column, the column cannot be properly evaluated. The application of this specification is particularly limited for composite hollow RC columns. The composite hollow RC column consists of transverse, longitudinal reinforcements, cover concrete, core concrete, and an inner tube inserted in the hollow face. It increases the ductility, strength, and stiffness in composite hollow RC columns. This paper proposes a modified equation for economics and rational design through investigation of displacement ductility when applying the existing specifications at the composite hollow RC column.
Moreover, a parametric study was performed to evaluate the detailed behavior. Using these results, a calculation method of economic transverse reinforcements is proposed.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002089601
|
oai_dc
|
A study of the replacement of desulphurization slag for sand to ready-mixed soil materials (RMSM)
|
A study of the replacement of desulphurization slag for sand to ready-mixed soil materials (RMSM)
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yi-Fang Shiha(National Kaohsiung University of Applied Sciences); Shih-Shong Tseng(National Kaohsiung University of Applied Sciences); Her-Yung Wang(National Kaohsiung University of Applied Sciences); Chih-Ting Wei(National Kaohsiung University of Applied Sciences)"
] |
After the industrial of steelmaking by-products are processed properly, they can be used in civil engineering, not only as a substitute for natural resources and to reduce costs, but also to provide environmental protection. This study used different amounts (10%, 20%, 30%, 40%,and 50%) of desulphurization slag to replace natural fine aggregates in ready-mixed soil materials, and tested the physical and fresh properties (slump, slump flow, tube flow, initial setting time, and bleeding) and hardened properties (compressive strength, ball drop, ultrasonic pulse velocity) of the materials. The variations between the performances of the materials with different mix proportions were discussed. When desulphurization slag is used in RMSM, the workability can be enhanced obviously significantly. When the replacement of desulphurization slag is 50%, the slump flow is increased by 110mm compared with the control group, and the initial setting time increases as the replacement increases, because of bleeding. When the replacement is 10% and 20%, the compressive strength at various ages is higher than that of the control group. When the replacement is 10%, the compressive strength at 7 days is higher than that of the control group by 60%, and the ultrasonic pulse velocity is proportional to the compressive strength, which increases with age and decrease as the replacement increases. An appropriate replacement can effectively accelerate construction, and allow projects to be finished ahead of schedule; therefore, an appropriate replacement, is applicable for ready-mixed soil materials.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002089595
|
oai_dc
|
Modeling the polypropylene fiber effect on compressive strength of self-compacting concrete
|
Modeling the polypropylene fiber effect on compressive strength of self-compacting concrete
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mehdi Nazarpour(Tabriz University); Ali Foroughi Asl(Tabriz University)"
] |
Although the self-compacting concrete (SCC) offers several practical and economic benefits and quality improvement in concrete constructions, in comparison with conventionally vibrated concretes confronts with autogenously chemical and drying shrinkage which causes the formation of different cracks and creates different problems in concrete structures. Using different fibers in the mix design and implementation of fibrous concrete, the problem can be solved by connecting cracks and micro cracks together and postponing the propagation of them. In this study an experimental investigation using response surface methodology (RSM) based on full factorial design has been undertaken in order to model and evaluate the polypropylene fiber effect on the fibrous self-compacting concrete and curing time, fiber percentage and fiber amount have been considered as input variables. Compressive strength has been measured and calculated as the output response to achieve a mathematical relationship between input variables. To evaluate the proposed model analysis of variance at a confidence level of 95% has been applied and finally optimum compressive strength predicted. After analyzing the data, it was found that the presented mathematical model is in very good agreement with experimental results. The overall results of the experiments confirm the validity of the proposed model and this model can be used to predict the compressive strength of fibrous self-compacting concrete.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002089593
|
oai_dc
|
Flexural behavior of concrete beams reinforced with CFRP prestressed prisms
|
Flexural behavior of concrete beams reinforced with CFRP prestressed prisms
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"J.F. Liang(Fundamental Science on Radioactive Geology and Exploration Technology Laboratory); Deng Yu(Guangxi University of Science and Technology); Bai Yu(Monash University)"
] |
An experimental investigation on the behaviour of concrete beams reinforced with various reinforcement, including ordinary steel bars, CFRP bars and CFRP prestressed concrete prisms(PCP). The main variable in the test program was the level of prestress and the cross section of PCP.The modes of failure and the crack width were observed. The results of load-deflection and load-crack width characteristics were discussed. The results showed that the CFRP prestressed concrete prisms as flexural reinforcement of concrete beams could limit deflection and crack width under service load and PCP can overcome the serviceability problems associated with the low elastic modulus/strength ratio of CFRP.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002089600
|
oai_dc
|
Simulation study on CFRP strengthened reinforced concrete beam under four-point bending
|
Simulation study on CFRP strengthened reinforced concrete beam under four-point bending
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Dongliang Zhang(Sichuan University); Qingyuan Wang(Sichuan University); Jiangfeng Dong(Sichuan University)"
] |
This paper presents numerical modeling of the structural behavior of CFRP (carbon fiber reinforced polymer) strengthened RC (reinforced concrete) beams under four-point bending. Simulation of debonding at the CFRP-concrete interface was focused, as it is the main failure mode of CFRP strengthened RC beams. Here, cohesive layer was employed to model the onset of debonding, which further helps to describe the post debonding behavior of the CFRP strengthened RC beam. In addition, the XFEM approach was applied to investigate the effects of crack localization on strain field on CFRP sheet and rebar. The strains obtained from the XFEM correlate better to the test results than that from CDP (concrete damaged plasticity) model. However, there is a large discrepancy between the experimental and simulated loaddisplacement relationships, which is due to the simplification of concrete constitutive law.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002089596
|
oai_dc
|
Properties of pervious concrete containing high-calcium fly ash
|
Properties of pervious concrete containing high-calcium fly ash
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"V. Sata(Khon Kaen University); C. Ngohpok(Khon Kaen University); P. Chindaprasirt(Khon Kaen University)"
] |
This paper presents the properties of pervious concrete containing high-calcium fly ash. The water to binder ratios of 0.19, 0.22, and 0.25, designed void ratios of 15, 20, and 25%, and fly ash replacements of 10, 20, and 30% were used. The results showed that the use of fly ash as partial replacement of Portland cement enhanced the mixing of paste resulting in a uniform mix and reduced amount of superplasticizer used in the mixture. The compressive strength and flexural strength of pervious concrete were slightly reduced with an increase in fly ash replacement level, while the abrasion resistance increased due mainly to the pozzolanic and filler effects. The compressive strength and flexural strengths at 28 days were still higher than 85% of the control concrete. The aggregate size also had a significant effect on the strength of pervious concrete. The compressive strength and flexural strength of pervious concrete with large aggregate were higher than that with small aggregate.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002089594
|
oai_dc
|
Assessment of design methods for punching through numerical experiments
|
Assessment of design methods for punching through numerical experiments
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Gregoria M. Kotsovou(HeriotWatt University); Gerasimos M. Kotsovos(Lithos Consulting Engineers); Emmanuel Vougioukas(National Technical University of Athens)"
] |
The work is intended to demonstrate that the loss of bond between concrete and flexural steel which led in recent years a number of flat-slab structures to punching collapse under service loading conditions is also relevant to ultimate limit-state design. It is based on a comparative study of the results obtained from numerical experiments on flat slab-column sub-assemblages. The slabs were designed for punching either in compliance with the EC2 code requirements, which do not allow for such loss of bond, or in accordance with the compressive force-path method which considers the loss of bond between concrete and the flexural reinforcement in tension as the primary cause of punching. The numerical experiments are carried out through the use of a nonlinear finite element analysis package for which, although ample published evidence of its validity exists, additional proof of its suitability for the purposes of the present work is presented.
|
토목공학
| null |
kci_detailed_000095.xml
|
|||
ART002089597
|
oai_dc
|
Software for biaxial cyclic analysis of reinforced concrete columns
|
Software for biaxial cyclic analysis of reinforced concrete columns
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Fatemeh Shirmohammadi(Walter P Moore Associates, Inc); Asad Esmaeily(Kansas State University)"
] |
Realistic assessment of the performance of reinforced concrete structural members like columns is needed for designing new structures or maintenance of the existing structural members. This assessment requires analytical capability of employing proper material models and cyclic rules and considering various load and displacement patterns. A computer application was developed to analyze the non-linear, cyclic flexural performance of reinforced concrete structural members under various types of loading paths including non-sequential variations in axial load and bi-axial cyclic load or displacement. Different monotonic material models as well as hysteresis rules, were implemented in a fiber-based moment-curvature and in turn force-deflection analysis, using proper assumptions on curvature distribution along the member, as in plastic-hinge models. Performance of the program was verified against analytical results by others, and accuracy of the analytical process and the implemented models were evaluated in comparison to the experimental results. The computer application can be used to predict the response of a member with an arbitrary cross section and various type of lateral and longitudinal reinforcement under different combinations of loading patterns in axial and bi-axial directions. On the other hand, the application can be used to examine analytical models and methods using proper experimental data.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002131693
|
oai_dc
|
Predicting of compressive strength of recycled aggregate concrete by genetic programming
|
Predicting of compressive strength of recycled aggregate concrete by genetic programming
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Gholamreza Abdollahzadeh(Babol University of Technology); Ehsan Jahani(University of Mazandaran); Zahra Kashir(Tabari University of Babol)"
] |
This paper, proposes 20 models for predicting compressive strength of recycled aggregate concrete (RAC) containing silica fume by using gene expression programming (GEP). To construct the models, experimental data of 228 specimens produced from 61 different mixtures were collected from the literature. 80% of data sets were used in the training phase and the remained 20% in testing phase.
Input variables were arranged in a format of seven input parameters including age of the specimen, cement content, water content, natural aggregates content, recycled aggregates content, silica fume content and amount of superplasticizer. The training and testing showed the models have good conformity with experimental results for predicting the compressive strength of recycled aggregate concrete containing silica fume.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002129375
|
oai_dc
|
Arrival direction effects of travelling waves on nonlinear seismic response of arch dams
|
Arrival direction effects of travelling waves on nonlinear seismic response of arch dams
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mehmet Akkose(Karadeniz Technical University)"
] |
The aim of this study is to investigate arrival direction effects of travelling waves on non-linear seismic response of arch dams. It is evident that the seismic waves may reach on the dam site from any direction. Therefore, this study considers the seismic waves arrive to the dam site with different angles, θ=0o, 15o, 30o, 45o, 60o, 75o, and 90o for non-linear analysis of arch dam-water-foundation interaction system. The N-S, E-W and vertical component of the Erzincan earthquake, on March 13, 1992, is used as the ground motion. Dam-water-foundation interaction is defined by Lagrangian approach in which a stepby- step integration technique is employed. The stress-strain behavior of the dam concrete is idealized using three-dimensional Drucker-Prager model based on associated flow rule assumption. The program NONSAP is employed in response calculations. The time-history of crest displacements and stresses of the dam are presented. The results obtained from non-linear analyses are compared with that of linear analyses.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002129376
|
oai_dc
|
The deformable multilaminate for predicting the Elasto-Plastic behavior of rocks
|
The deformable multilaminate for predicting the Elasto-Plastic behavior of rocks
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hadi Haeri(Islamic Azad University); V. Sarfarazi(Hamedan University of Technology)"
] |
In this paper, a multilaminate based model have been developed and presented to predict the strain hardening behavior of rock. In this multilaminate model, the stress–strain behavior of a material is obtained by integrating the mechanical response of an infinite number of predefined oriented planes passing through a material point. Essential features such as the variable deformations hypothesis and multilaminate model are discussed. The methodology to be discussed here is modeling of strains on the 13 laminates passing through a point in each loading step. Upon the presented methodology, more attention has been given to hardening in non-linear behaviour of rock in going from the peak to residual strengths. The predictions of the derived stress–strain model are compared to experimental results for marble, sandstone and dense Cambria sand. The comparisons demonstrate the ability of this model to reproduce accurately the mechanical behavior of rocks.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002129379
|
oai_dc
|
A review of experimental and numerical investigations about crack propagation
|
A review of experimental and numerical investigations about crack propagation
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Vahab Sarfarazi(Hamedan University of Technology); Hadi Haeri(Islamic Azad University)"
] |
A rock mass containing non-persistent joints can only fail if the joints propagate and coalesce through an intact rock bridge. Shear strength of rock mass containing non-persistent joints is highly affected by the both, mechanical behavior and geometrical configuration of non-persistent joints located in a rock mass. Existence of rock joints and rock bridges are the most important factors complicating mechanical responses of a rock mass to stress loading. The joint-bridge interaction and bridge failure dominates mechanical behavior of jointed rock masses and the stability of rock excavations.The purpose of this review paper is to present techniques, progresses and the likely future development directions in experimental and numerical modelling of a non-persistent joint failure behaviour. Such investigation is essential to study the fundamental failures occurring in a rock bridge, for assessing anticipated and actual performances of the structures built on or in rock masses. This paper is divided into two sections. In the first part, experimental investigations have been represented followed by a summarized numerical modelling. Experimental results showed failure mechanism of a rock bridge under different loading conditions. Also effects of the number of non-persistent joints, angle between joint and a rock bridge, lengths of the rock bridge and the joint were investigated on the rock bridge failure behaviour. Numerical simulation results are used to validate experimental outputs.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002129381
|
oai_dc
|
Damage and fracture processes of concrete using acoustic emission parameters
|
Damage and fracture processes of concrete using acoustic emission parameters
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Fan Xiangqian(Nanjing Hydraulic Research Institute); Hu Shaowei(Nanjing Hydraulic Research Institute); Lu Jun(Nanjing Hydraulic Research Institute)"
] |
In order to observe the internal damage of concrete in real time, we introduced acoustic emission nondestructive detecting technology into a series of fracture tests; the test results revealed the whole process that concrete undergoes when it sustains damage that leads to failure, according to the change rules of the acoustic emission parameters. The results showed that both the initiation and unstable loads can be accurately determined using the abrupt change of the acoustic emission rate curves and the turning point of the acoustic emission parameters’ accumulative curves. The whole process, from damage to failure, includes five phases, beginning with damage, such as cracking, a stable crack growth process, a critical unstable stage, and unstable propagation. The brittle fracture characteristics of concrete change when steel bars are joined, because the steel bars and the concrete structure bond, which causes an increase in the acoustic emission signals within the fracture process of the reinforced concrete. The unstable propagation stage is also extended. Our research results provide a valid methodology and technical explanations, which can help researchers to monitor the cracking process of concrete structures, in real time, during actual projects.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002129374
|
oai_dc
|
Behaviour of RC Beams with non-bonded flexural reinforcement: A numerical experiment
|
Behaviour of RC Beams with non-bonded flexural reinforcement: A numerical experiment
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Gregoria M. Kotsovou(HeriotWatt University); Gerasimos M. Kotsovos(Lithos Consulting Engineers)"
] |
The present work is concerned with a numerical investigation of the behaviour of reinforcedconcrete beams with non-bonded flexural tension reinforcement. The numerically-established behaviour of such beams with and without transverse reinforcement is compared with its counterpart of similar beams with bonded reinforcement. From the comparison, it is found that the development of bond anywhere within the shear span inevitably leads to inclined cracking which is the cause of ‘shear’ failure. On the other hand, the lack of bond within the shear span of the beams is found, not only to prevent cracking within the shear span, but, also, to lead to a flexural type of failure preceded by the formation of horizontal splitting of concrete in the compressive zone. It is also found that delaying the extension of horizontal splitting through the provision of transverse reinforcement in the beam mid span can lead to flexural failure after yielding of the tension reinforcement. Yielding of the tension reinforcement before the horizontal splitting of the compressive zone may also be achieved by reducing the amount of the latter reinforcement.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002129378
|
oai_dc
|
Parametrical study of the behavior of exterior unreinforced concrete beam-column joints through numerical modeling
|
Parametrical study of the behavior of exterior unreinforced concrete beam-column joints through numerical modeling
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Matheus F. A. Silva(University of Sao Paulo); Vladimir G. Haach(1University of Sao Paulo)"
] |
Exterior beam-column joints are structural elements that ensure connection between beams and columns. The joint strength is generally assumed to be governed by the structural element of lowest load capacity (beam or column), however, the joint may be the weakest link. The joint shear behavior is still not well understood due to the influence of several variables, such as geometry of the connection, stress level in the column, concrete strength and longitudinal beam reinforcement. A parametrical study based only on experiments would be impracticable and not necessarily exposes the failure mechanisms. This paper reports on a set of numerical simulations conducted in DIANA® software for the investigation of the shear strength of exterior joints. The geometry of the joints and stress level on the column are the variables evaluated.
Results have led to empirical expressions that provide the shear strength of unreinforced exterior beamcolumn joints.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002129385
|
oai_dc
|
Development of fine grained concretes for textile reinforced cementitious composites
|
Development of fine grained concretes for textile reinforced cementitious composites
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Esma Gizem Daskiran(Istanbul Technical University); Mehmet M. Daskiran(Istanbul Technical University); Mustafa Gencoglu(Istanbul Technical University)"
] |
A new innovative composite material is textile reinforced cementitious composite (TRCC). To achieve high flexural performance researchers suggest polymermodification of TRCCmatrices. In this study, nine readymix repair mortars commonly used in construction industry and the production of TRCC elements were examined.
Mechanical properties such as compressive and flexural strength, drying shrinkage were studied. Being a significant durability concern, alkali silica reaction tests were performed according to related standards. Results showed that, some ready repair mortar mixes are potentially reactive due to the alkali silica reaction. Two of the ready mortar mixes labelled as non-shrinkage in their technical data sheets showed the highest shrinkage. In this experiment, researchers designed new matrices. These matrices were fine grained concretes modified with polymer additives; latexes and redispersible powders. Two latexes and six redispersible powder polymers were used in the study.
Mechanical properties of fine grained concretes such as compressive and flexural strengthswere determined.Results showed that some of the fine grained concretes cast with redispersible powders had higher flexural strength than ready mix repair mortars at 28 days. Matrix composition has to be designed for a suitable consistency for planned production processes ofTRCCandmechanical properties for load-carrying capacity.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002112860
|
oai_dc
|
The effect of non-persistent joints on sliding direction of rock slopes
|
The effect of non-persistent joints on sliding direction of rock slopes
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Vahab Sarfarazi(Hamedan University of Technology); Hadi Haeri(Islamic Azad University); Alireza Khaloo(Sharif University of Technology)"
] |
In this paper an approach was described for determination of direction of sliding block in rock slopes containing planar non-persistent open joints. For this study, several gypsum blocks containing planar non-persistent open joints with dimensions of 15×15×15 cm were build. The rock bridges occupy 45, 90 and 135 cm2 of total shear surface (225cm2), and their configuration in shear plane were different. From each model, two similar blocks were prepared and were subjected to shearing under normal stresses of 3.33 and 7.77 kg/cm-2. Based on the change in the configuration of rock-bridges, a factor called the Effective Joint Coefficient (EJC) was formulated, that is the ratio of the effective joint surface that is in front of the rock-bridge and the total shear surface. In general, the failure pattern is influenced by the EJC while shear strength is closely related to the failure pattern. It is observed that the propagation of wing tensile cracks or shear cracks depends on the EJC and the coalescence of wing cracks or shear cracks dominates the eventual failure pattern and determines the peak shear load of the rock specimens. So the EJC is a key factor to determine the sliding direction in rock slopes containing planar non-persistent open joints.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002112864
|
oai_dc
|
Optimum seismic design of reinforced concrete frame structures
|
Optimum seismic design of reinforced concrete frame structures
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Sadjad Gharehbaghi(Behbahan Khatam Alanbia University of Technology); Abbas Moustafa(Minia University); Eysa Salajegheh(Shahid Bahonar University of Kerman)"
] |
This paper proposes an automated procedure for optimum seismic design of reinforced concrete (RC) frame structures. This procedure combines a smart pre-processing using a Tree Classification Method (TCM) and a nonlinear optimization technique. First, the TCM automatically creates sections database and assigns sections to structural members. Subsequently, a real valued model of Particle Swarm Optimization (PSO) algorithm is employed in solving the optimization problem. Numerical examples on design optimization of three low- to high-rise RC frame structures under earthquake loads are presented with and without considering strong column-weak beam (SCWB) constraint. Results demonstrate the effectiveness of the TCMin seismic design optimization of the structures.
|
토목공학
| null |
kci_detailed_000096.xml
|
|||
ART002112867
|
oai_dc
|
A study of the fresh properties of Recycled ready-mixed soil materials (RRMSM)
|
A study of the fresh properties of Recycled ready-mixed soil materials (RRMSM)
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Wen-Ling Huang(National Kaohsiung University of Applied Sciences); Her-Yung Wang(National Kaohsiung University of Applied Sciences); Chen Jheng-Hung(National Kaohsiung University of Applied Sciences)"
] |
Climate anomalies in recent years, numerous natural disasters caused by landslides and a large amount of entrained sands and stones in Taiwan have created significant disasters and greater difficulties in subsequent reconstruction. How to respond to these problems efficaciously is an important issue. In this study, the sands and stones were doped with recycled materials (waste LCD glass sand, slag powder), and material was mixed for recycled ready-mixed soil. The study is based on security and economic principles, using flowability test to determine the water-binder ratio (W/B=2.4, 2.6, and 2.8), a fixed soil: sand ratio of 6:4 and a soil: sand: glass ratio of 6:2:2 as fine aggregate. Slag (at concentrations of 0%, 20%, and 40%) replaced the cement. The following tests were conducted: flowability, initial setting time, unit weight, dropweight and compressive strength. The results show that the slump values are 220 -290 mm, the slump flow values are 460 -1030 mm, and the tube flow values are 240-590 mm, all conforming to the objectives of the design. The initial setting times are 945-1695 min. The unit weight deviations are 0.1-0.6%. The three groups of mixtures conform to the specification, being below 7.6 cm in the drop-weight test. In the compressive strength test, the water-binder ratios for 2.4 are optimal (13.78-17.84 kgf/cm2). The results show that Recycled ready-mixed soil materials (RRMSM) possesses excellent flowability. The other properties, applied to backfill engineering, can effectively save costs and are conducive to environmental protection.
|
토목공학
| null |
kci_detailed_000096.xml
|
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