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ART001775160
|
oai_dc
|
Polynomial modeling of confined compressive strength and strain of circular concrete columns
|
Polynomial modeling of confined compressive strength and strain of circular concrete columns
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hsing-Chih Tsai(National Taiwan University of Science an)"
] |
This paper improves genetic programming (GP) and weight genetic programming (WGP) and proposes soft-computing polynomials (SCP) for accurate prediction and visible polynomials. The proposed genetic programming system (GPS) comprises GP, WGP and SCP. To represent confined compressive strength and strain of circular concrete columns in meaningful representations, this paper conducts sensitivity analysis and applies pruning techniques. Analytical results demonstrate that all proposed models perform well in achieving good accuracy and visible formulas; notably, SCP can model problems in polynomial forms. Finally, concrete compressive strength and lateral steel ratio are identified as important to both confined compressive strength and strain of circular concrete columns. By using the suggested formulas, calculations are more accurate than those of analytical models. Moreover, a formula is applied for confined compressive strength based on current data and achieves accuracy comparable to that of neural networks.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001775156
|
oai_dc
|
Mechanical properties of natural fiber-reinforced normal strength and high-fluidity concretes
|
Mechanical properties of natural fiber-reinforced normal strength and high-fluidity concretes
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Joo-seok Kim(Kyungpook National University); Hyoung-ju Lee(Kyungpook National University); Yeol Choi(Kyungpook National University)"
] |
An experimental investigation of mechanical properties of jute fiber-reinforced concrete (JFRC) has been reported for making a suitable construction material in terms of fiber reinforcement. Two jute fiber reinforced concretes, called jute fiber reinforced normal strength concrete (JFRNSC) and jute fiber- reinforced high-fluidity concrete (JFRHFC), were tested in compression, flexure and splitting tension. Compressive, flexural and splitting tensile strengths of specimens were investigated to four levels of jute fiber contents by volume fraction. From the test results, Jute fiber can be successfully used for normal strength concrete (NSC) and high-fluidity concrete (HFC). Particularly, HFC with jute fibers shows relatively higher improvement of strength property than that of normal strength concrete.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001775157
|
oai_dc
|
Evaluation of the different genetic algorithm parameters and operators for the finite element model updating problem
|
Evaluation of the different genetic algorithm parameters and operators for the finite element model updating problem
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yildirim Serhat Erdogan(Istanbul Technical University); Pelin Gundes Bakir(Istanbul Technical University)"
] |
There is a wide variety of existing Genetic Algorithms (GA) operators and parameters in the literature. However, there is no unique technique that shows the best performance for different classes of optimization problems. Hence, the evaluation of these operators and parameters, which influence the effectiveness of the search process, must be carried out on a problem basis. This paper presents a comparison for the influence of GA operators and parameters on the performance of the damage identification problem using the finite element model updating method (FEMU). The damage is defined as reduction in bending rigidity of the finite elements of a reinforced concrete beam. A certain damage scenario is adopted and identified using different GA operators by minimizing the differences between experimental and analytical modal parameters. In this study, different selection, crossover and mutation operators are compared with each other based on the reliability, accuracy and efficiency criteria. The exploration and exploitation capabilities of different operators are evaluated. Also a comparison is carried out for the parallel and sequential GAs with different population sizes and the effect of the multiple use of some crossover operators is investigated. The results show that the roulettewheel selection technique together with real valued encoding gives the best results. It is also apparent that the Non-uniform Mutation as well as Parent Centric Normal Crossover can be confidently used in the damage identification problem. Nevertheless the parallel GAs increases both computation speed and the efficiency of the method.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001751733
|
oai_dc
|
Review of design parameters for FRP-RC members detailed according to ACI 440.1R-06
|
Review of design parameters for FRP-RC members detailed according to ACI 440.1R-06
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Fares Jnaid(Syracuse University); Riyad Aboutaha(Syracuse University)"
] |
This paper investigates the parameters that control the design of Fiber Reinforced Polymer (FRP) reinforced concrete flexural members proportioned following the ACI 440.1R-06. It investigates the critical parameters that control the flexural design, such as the deflection limits, crack limits, flexural capacity,concrete compressive strength, beam span and cross section, and bar diameter, at various Mean-Ambient Temperatures (MAT). The results of this research suggest that the deflection and cracking requirements are the two most controlling limits for FRP reinforced concrete flexural members.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001751732
|
oai_dc
|
Rock wool wastes as a supplementary cementitious material replacement in cement-based composites
|
Rock wool wastes as a supplementary cementitious material replacement in cement-based composites
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Wei-Ting Lin(National Ilan University); An Cheng(National Ilan University); Ran Huang(National Taiwan Ocean University); Yuan-Chieh Wu(Atomic Energy Council); Ta-Yuan Han(National Taiwan Ocean University)"
] |
The use of rock wool waste, an industrial by-product, in cement-based composites has positive effects on the environment because it reduces the problems associated rock wool disposal. The experiments in this study tested cement-based composites using various rock wool waste contents (10, 20, 30 and 40% by weight of cement) as a partial replacement for Portland cement in mortars. The pozzolanic strength activity test, flow test, compressive strength test, dry shrinkage test, absorption test, initial surface absorption test and scanning electron microscope observations were conducted to evaluate the properties of cement-based composites. Test results demonstrate that the pozzolanic strength activity index for rock wool waste specimens is 103% after 91 days. The inclusion of rock wool waste in cement-based composites decreases its dry shrinkage and initial surface absorption, and increases its compressive strength. These improved properties are the result of the dense structure achieved by the filling effect and pozzolanic reactions of the rock wool waste. The addition of 30% and 10% rock wool wastes to cement is the optimal amount based on the results of compressive strength and initial surface absorption for a w/cm of 0.35 and 0.55, respectively. Therefore, it is feasible to utilize rock wool waste as a partial replacement of cement in cement-based composites.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001751734
|
oai_dc
|
FE analysis of RC structures using DSC model with yield surfaces for tension and compression
|
FE analysis of RC structures using DSC model with yield surfaces for tension and compression
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A.H. Akhaveissy(Razi University); C.S. Desai(University of Arizona); D. Mostofinejad(Isfahan University of Technology); A. Vafai(Sharif University of Technology)"
] |
The nonlinear finite element method with eight noded isoparametric quadrilateral element for concrete and two noded element for reinforcement is used for the prediction of the behavior of reinforcement concrete structures. The disturbed state concept (DSC) including the hierarchical single surface (HISS) plasticity model with associated flow rule with modifications is used to characterize the constitutive behavior of concrete both in compression and in tension which is named DSC/HISS-CT. The HISS model is applied to shows the plastic behavior of concrete, and DSC for microcracking, fracture and softening simulations of concrete. It should be noted that the DSC expresses the behavior of a material element as a mixture of two interacting components and can include both softening and stiffening, while the classical damage approach assumes that cracks (damage) induced in a material treated acts as a void, with no strength. The DSC/HISS-CT is a unified model with different mechanism, which expresses the observed behavior in terms of interacting behavior of components; thus the mechanism in the DSC is much different than that of the damage model, which is based on physical cracks which has no strength and interaction with the undamaged part. This is the first time the DSC/HISS-CT model, with the capacity to account for both compression and tension yields, is applied for concrete materials. The DSC model allows also for the characterization of non-associative behavior through the use of disturbance. Elastic perfectly plastic behavior is assumed for modeling of steel reinforcement. The DSC model is validated at two levels: (1) specimen and (2) practical boundary value problem. For the specimen level, the predictions are obtained by the integration of the incremental constitutive relations. The FE procedure with DSC/HISS-CT model is used to obtain predictions for practical boundary value problems. Based on the comparisons between DSC/HISS-CT predictions, test data and ANSYS software predictions, it is found that the model provides highly satisfactory predictions. The model allows computation of microcracking during deformation leading to the fracture and failure; in the model, the critical disturbance, Dc, identifies fracture and failure.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001751735
|
oai_dc
|
Stress-strain behavior and toughness of high-performance steel fiber reinforced concrete in compression
|
Stress-strain behavior and toughness of high-performance steel fiber reinforced concrete in compression
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"P. Ramadoss(Pondicherry Engineering College); K. Nagamani(Anna University)"
] |
The complete stress-strain behavior of steel fiber reinforced concrete in compression is needed for the analysis and design of structures. An experimental investigation was carried out to generate the complete stress-strain curve of high-performance steel fiber reinforced concrete (HPSFRC) with a strength range of 52–80 MPa. The variation in concrete strength was achieved by varying the water-to-cementitious materials ratio of 0.40-0.25 and steel fiber content (Vf = 0.5, 1.0 and 1.5% with l/d = 80 and 55) in terms of fiber reinforcing parameter, at 10% silica fume replacement. The effects of these parameters on the shape of stress-strain curves are presented. Based on the test data, a simple model is proposed to generate the complete stress-strain relationship for HPSFRC. The proposed model has been found to give good correlation with the stress-strain curves generated experimentally. Inclusion of fibers into HPC improved the ductility considerably. Equations to quantify the effect of fibers on compressive strength, strain at peak stress and toughness of concrete in terms of fiber reinforcing index are also proposed, which predicted the test data quite accurately. Compressive strength prediction model was validated with the strength data of earlier researchers with an absolute variation of 2.1%.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001751736
|
oai_dc
|
Numerical analysis of thermal and composite stresses in prestressed concrete pavements
|
Numerical analysis of thermal and composite stresses in prestressed concrete pavements
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Fereidoon Moghadas Nejad(Amirkabir University of Technology); Sepehr Ghafari(Amirkabir University of Technology); Shahriar Afandizadeh(University of Science and Technology)"
] |
One of the major benefits of the pre-stressed concrete pavements is the omission of tension in concrete that results in a reduction of cracks in the concrete slabs. Therefore, the life of the pavement is increased as the thickness of the slabs is reduced. One of the most important issues in dealing with the prestressed concrete pavement is determination of the magnitude of the pre-stress. Three dimensional finite element analyses are conducted in this research to study the pre-stress under various load (Boeing 777) and thermal gradient combinations. The model was also analyzed under temperature gradients without the presence of traffic loading and the induced stresses were compared with those from theoretical relationships. It was seen that the theoretical relationships result in conservative values for the stress.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001790145
|
oai_dc
|
Construction stage effect on the dynamic characteristics of RC frame using operational modal analysis
|
Construction stage effect on the dynamic characteristics of RC frame using operational modal analysis
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mehmet Emin Arslan(Karadeniz Technical University); Ahmet Durmuş(Karadeniz Technical University)"
] |
In this study, dynamic characteristics such as natural frequencies, mode shapes and damping ratios of RC frame is determined for different construction stages using Operational Modal Analyses method under ambient vibration. Full scaled, one bay and one story RC frames are selected as an application for different construction stages such as plane, brick in-filled and brick in-filled with plaster. The RC frame is vibrated by natural excitations with small impact effects and the response signals are measured using sensitive accelerometers during ambient vibration tests. Measurement time-frequency span and effective mode number are determined by considering similar studies in literature. Sensitive seismic accelerometers are used to collect signals obtained from the experimental tests. To obtain experimental dynamic characteristics, output-only system identification technique is employed namely; Enhanced Frequency Domain Decomposition technique in the frequency domain. It is demonstrated that the ambient vibration measurements are enough to identify the most significant modes of RC frames.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001790119
|
oai_dc
|
Actual microstructure-based numerical method for mesomechanics of concrete
|
Actual microstructure-based numerical method for mesomechanics of concrete
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S. Chen(The University of Hong Kong); A. K. H. Kwan(The University of Hong Kong); Z.Q. Yue(The University of Hong Kong)"
] |
This paper presents an actual microstructure-based numerical method to investigate the mechanical properties of concrete at mesoscopic level. Digital image processing technique is used to capture the concrete surface image and generate the actual 3-phase microstructure of the concrete, which consists of aggregate, matrix and interfacial transition zones. The microstructure so generated is then transformed into a mesh or grid for numerical analysis. A finite difference code FLAC2D is used for the numerical analysis to simulate the mechanical responses and failure patterns of the concrete. Several cases of concrete with different degrees of material heterogeneity and under different compression loading conditions have been analysed. From the numerical results, the effects of the internal material heterogeneities as well as the external confining stresses are studied. It is shown that the material heterogeneities arising from the presence of different phases and the existence of interfacial transition zones have great influence on the overall mechanical behaviour of concrete and that the numerically simulated behaviour of concrete with or without confining stresses applied agrees quite well with the general observations reported in the literature.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001790122
|
oai_dc
|
Modelling dowel action of discrete reinforcing bars for finite element analysis of concrete structures
|
Modelling dowel action of discrete reinforcing bars for finite element analysis of concrete structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A. K. H. Kwan(The University of Hong Kong); P.L. Ng(The University of Hong Kong)"
] |
In the finite element analysis of reinforced concrete structures, discrete representation of the steel reinforcing bars is considered advantageous over smeared representation because of the more realistic modelling of their bond-slip behaviour. However, there is up to now limited research on how to simulate the dowel action of discrete reinforcing bars, which is an important component of shear transfer in cracked concrete structures. Herein, a numerical model for the dowel action of discrete reinforcing bars is developed. It features derivation of the dowel stiffness based on the beam-on-elastic-foundation theory and direct assemblage of the dowel stiffness matrix into the stiffness matrices of adjoining concrete elements. The dowel action model is incorporated in a nonlinear finite element program based on secant stiffness formulation and application to deep beams tested by others demonstrates that the incorporation of dowel action can improve the accuracy of the finite element analysis.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001790128
|
oai_dc
|
Evaluation of early age mechanical properties of concrete in real structure
|
Evaluation of early age mechanical properties of concrete in real structure
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jiachun Wang(Xiamen University of Technology); Peiyu Yan(Tsinghua University)"
] |
The curing temperature is known to influence the rate of mechanical properties development of early age concrete. In realistic sites the temperature of concrete is not isothermal 20˚C, so the paper measured adiabatic temperature increases of four different concretes to understand heat emission during hydration at early age. The temperature-matching curing schedule in accordance with adiabatic temperature increase is adopted to simulate the situation in real massive concrete. The specimens under temperature-matching curing are subjected to realistic temperature for first few days as well as adiabatic condition. The mechanical properties including compressive strength, splitting strength and modulus of elasticity of concretes cured under both temperature-matching curing and isothermal 20˚C curing are investigated. The results denote that comparing temperature-matching curing with isothermal 20˚C curing, the early age concretes mechanical properties are obviously improved, but the later mechanical properties of concretes with pure Portland and containing silica fume are decreased a little and still increased for concretes containing fly ash and slag. On this basement using an equivalent age approach evaluates mechanical properties of early age concrete in real structures, the model parameters are defined by the compressive strength test, and can predict the compressive strength, splitting strength and elasticity modulus through measuring or calculating by finite element method the concreted temperature at early age, and the method is valid, which is applied in a concrete wall for evaluation of crack risking.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001790143
|
oai_dc
|
Damage analysis of arch dam under blast loading
|
Damage analysis of arch dam under blast loading
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Xinhua Xue(Sichuan University); Xingguo Yang(Sichuan University); Wohua Zhang(Zhejiang University)"
] |
This paper examines the dynamic response of an arch dam subjected to blast loading. A damage model is developed for three dimensional analysis of arch dams. The modified Drucker-Prager criterion is adopted as the failure criteria of the damage evolution in concrete. Then, Xiluodu arch dam serves as an example to simulate the failure behaviors of structures with the proposed model. The results obtained using the proposed model can reveal the reliability degree of the safe operation level of the high arch dam system as well as the degree of potential failure, providing a reliable basis for risk assessment and risk control
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001790146
|
oai_dc
|
Reliability assessment of concrete bridges subject to corrosion-induced cracks during life cycle using artificial neural networks
|
Reliability assessment of concrete bridges subject to corrosion-induced cracks during life cycle using artificial neural networks
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Afshin Firouzi(Islamic Azad University); Alireza Rahai(Amir Kabir University of Technology)"
] |
Corrosion of RC bridge decks eventually leads to delamination, severe cracking and spalling of the concrete cover. This is a prevalent deterioration mechanism and demands for the most costly repair interventions during the service life of bridges worldwide. On the other hand, decisions for repairs are usually made whenever the extent of a limit crack width, reported in routine visual inspections, exceeds an acceptable threshold level. In this paper, while random fields are applied to account for spatial variation of governing parameters of the corrosion process, an analytical model is used to simulate the corrosion induced crack width. However when dealing with random fields, the Monte Carlo simulation is apparently an inefficient and time consuming method, hence the utility of neural networks as a surrogate in simulation is investigated and found very promising. The proposed method can be regarded as an invaluable tool in decision making concerning maintenance of bridges.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001790125
|
oai_dc
|
Computational impact responses of reinforced concrete slabs
|
Computational impact responses of reinforced concrete slabs
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S.N. Mokhatar(Universiti Tun Hussein Onn Malaysia); A.B.H. Kueh(Universiti Teknologi Malaysia); R. Abdullah(Universiti Teknologi Malaysia)"
] |
The responses of reinforced concrete slabs subject to an impact loading near the ultimate load range are explored. The analysis is carried out on a simply supported rectangular reinforced concrete slab using a nonlinear explicit dynamic procedure and considering three material models: Drucker-Prager, modified Drucker-Prager, and concrete damaged plasticity, available in the commercial finite element software, ABAQUS/Explicit. For comparison purposes, the impact force-time response, steel reinforcement failure, and concrete perforation pattern are verified against the existing experimental results. Also, the effectiveness of mesh density and damage wave propagation are studied independently. It is shown that the presently adopted finite element procedure is able to simulate and predict fairly accurate the behavior of reinforced concrete slab under impact load. More detailed investigations are however demanded for the justification of effects coming from an imperfect projectile orientation as well as the load and structural surface conditions, including the impulsive contacted state, which are inevitable in an actual impact environment.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001769831
|
oai_dc
|
A reliable approach for determining concrete strength in structures by using cores
|
A reliable approach for determining concrete strength in structures by using cores
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ayşegül Durmuş(Karadeniz Technical University); Hasan Tahsin Öztürk(Karadeniz Technical University); Ahmet Durmuş(Karadeniz Technical University)"
] |
As known, concrete classes are described as strength of standard specimens produced and kept in ideal conditions, not including reinforcement and not subjected to any load effect before. Under the circumstances, transforming core strengths to the standard specimen strength is necessary and considering all parameters, affected on the core strength, is inevitable. In fact, effects of the reinforcement and the load history on concrete strength are generally neglected when these mentioned transforms are performing. The main purpose of this paper is investigating the effects of the reinforcement and the load history on the core strength. This investigation is experimentally performed on cores drilled from specimens having different keeping conditions, reinforced, unreinforced, subjected to bending and central pressure in various proportions of failure load during specified periods. Obtained results show that the importance of these effects cannot be neglected.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001769830
|
oai_dc
|
A new method solving the temperature field of concrete around cooling pipes
|
A new method solving the temperature field of concrete around cooling pipes
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Zhenyang Zhu(Hydrochina Huadong Engineering Corporation); Sheng Qiang(Hohai University,); Weimin Chen(Hydrochina Huadong Engineering Corporation)"
] |
When using the conventional finite element method, a great number of grid nodes are necessary to describe the large and uneven temperature gradients in the concrete around cooling pipes when calculating the temperature field of mass concrete with cooling pipes. In this paper, the temperature gradient properties of the concrete around a pipe were studied. A new calculation method was developed based on these properties and an explicit iterative algorithm. With a small number of grid nodes, both the temperature distribution along the cooling pipe and the temperature field of the concrete around the water pipe can be correctly calculated with this new method. In conventional computing models, the cooling pipes are regarded as the third boundary condition when solving a model of concrete with plastic pipes, which is an approximate way. At the same time, the corresponding parameters have to be got by expensive experiments and inversion. But in the proposed method, the boundary condition is described strictly, and thus is more reliable and economical. And numerical examples were used to illustrate that this method is accurate, efficient and applicable to the actual engineering.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001769832
|
oai_dc
|
Nonlinear finite element analysis of loading transferred from column to socket base
|
Nonlinear finite element analysis of loading transferred from column to socket base
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Özgür ANIL(Gazi University); Burak UYAROĞLU(Gazi University)"
] |
Since the beginning of the 90 s, depending on the growth of the industrial sector in Turkey,factory constructions have been increased. The cost of precast concrete buildings is lower than the steel ones for this reason the precast structural systems are used more. Precast concrete structural elements are mostly as strong as not to have damage in the earthquake but weakness of connections between elements causes unexpected damages of structure during earthquake. When looking at the previous researches, it can be seen that there is a lack of studies about socket type base connections although there were many experimental and analytical studies about the connections of precast structural elements. The aim of this study is to investigate the stress transfer mechanism between column and the socket base wall with finite element method. For the finite element analysis ANSYS software was used. A finite element model was created which is the simulation of experimental research executed by Canha et al. (2009) under vertical and horizontal forces. Results of experimental research and finite element analysis were compared to create a successful simulation of experimental program. After determining the acceptable parameters, models of socket bases were created. Model dimensions were chosen according to square section column sizes 400, 450, 500, 550 and 600 mm which were mostly used in industrial buildings. As a result of this study, stress distribution at center section of the socket base models were observed and it is found that stress distribution affects triangular at the half of socket bottom and top.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001769826
|
oai_dc
|
Shear strength of full-scale steel fibre-reinforced concrete beams without stirrups
|
Shear strength of full-scale steel fibre-reinforced concrete beams without stirrups
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Nino Spinella(University of Messina)"
] |
Although shear reinforcement in beams typically consists of steel bars bent in the form of stirrups or hoops, the addition of deformed steel fibres to the concrete has been shown to enhance shear resistance and ductility in reinforced concrete beams. This paper presents a model that can be used to predict the shear strength of fibrous concrete rectangular members without stirrups. The model is an extension of the plasticity-based crack sliding model originally developed for plain concrete beams. The crack sliding model has been improved in order to take into account several aspects: the arch effect for deep beams, the postcracking tensile strength of steel fibre reinforced concrete and its ability to control sliding along shear cracks, and the mitigation of the shear size effect due to presence of fibres. The results obtained by the model have been validated by a large set of experimental tests taken from literature, compared with several models proposed in literature, and numerical analyses are carried out showing the influence of fibres on the beam failure mode.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001769829
|
oai_dc
|
Modelling of strains in reinforced concrete flexural members using alpha-stable distribution
|
Modelling of strains in reinforced concrete flexural members using alpha-stable distribution
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"K. Balaji Rao(CSIR-Structural Engineering Research Centre); M. B. Anoop(CSIR-Structural Engineering Research Centre); K. Kesavan(CSIR-Structural Engineering Research Centre); S. R. Balasubramanian(CSIR-Structural Engineering Research Centre); K. Ravisankar(CSIR-Structural Engineering Research Centre); Nagesh R. Iyer(CSIR-Structural Engineering Research Centre)"
] |
Large fluctuations in surface strain at the level of steel are expected in reinforced concrete flexural members at a given stage of loading due to the emergent structure (emergence of new crack patterns). This has been identified in developing deterministic constitutive models for finite element applications in Ibrahimbegovic et al. (2010). The aim of this paper is to identify a suitable probability distribution for describing the large deviations at far from equilibrium points due to emergent structures, based on phenomenological, thermodynamic and statistical considerations. Motivated by the investigations reported by Prigogine (1978) and Rubi (2008), distributions with heavy tails (namely, alpha-stable distributions) are proposed for modeling the variations in strain in reinforced concrete flexural members to account for the large fluctuations. The applicability of alpha-stable distributions at or in the neighborhood of far from equilibrium points is examined based on the results obtained from carefully planned experimental investigations, on seven reinforced concrete flexural members. It is found that alpha-stable distribution performs better than normal distribution for modeling the observed surface strains in reinforced concrete flexural members at these points.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001769828
|
oai_dc
|
Nonlinear finite element analysis of torsional R/C hybrid deep Tbeam with opening
|
Nonlinear finite element analysis of torsional R/C hybrid deep Tbeam with opening
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ade Lisantono(Universitas Atma Jaya Yogyakarta)"
] |
A nonlinear finite element analysis of R/C hybrid deep T-beam with web opening subjected to pure torsion is presented. Hexahedral 8-nodes and space truss element were used for modeling concrete and reinforcement. The reinforcement was assumed perfectly bonded to the corresponding nodes of the concrete element. The constitutive relations for concrete and reinforcement are based on the modified field theory and elastic perfectly plastic. The smear crack approach was adopted for modeling the crack. The torque-twist angle relationship curve based on the finite element analysis was compared to the experimental results. The comparison shows that the curve of torque-twist angle predicted by the nonlinear finite element analysis is linear before cracking and close to the experimental result. After cracking, the curve becomes nonlinear and stiffer compared to the experimental result.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001769827
|
oai_dc
|
Reinforcement design for the anchorage of externally prestressed bridges with “tensile stress region”
|
Reinforcement design for the anchorage of externally prestressed bridges with “tensile stress region”
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"C. Liu(Tongji University); B. Jung(Bauhaus-Universität); G. Morgentha(Bauhaus-Universität); D. Xu(Tongji University)"
] |
Two-dimensional tensile stresses are occurring at the back of the anchorage of the tendons of prestressed concrete bridges. A new method named “tensile stress region” for the design of the reinforcement is presented in this paper. The basic idea of this approach is the division of an anchor block into several slices, which are described by the tensile stress region. The orthogonal reinforcing wire mesh can be designed in each slice to resist the tensile stresses. Additionally the sum of the depth of every slice defined by the tensile stress region is used to control the required length of the longitudinal reinforcement bars. An example for the reinforcement design of an anchorage block of an external prestressed concrete bridge is analyzed by means of the new presented method and a finite element model is established to compare the results. Furthermore the influence of the transverse and vertical prestressing on the ordinary reinforcement design is taken into account. The results show that the amount of reinforcement bars at the anchorage block is influenced by the layout of the transverse and the vertical prestressing tendons. Using the “tensile stress region” method, the ordinary reinforcement bars can be designed more precisely compared to the design codes, and arranged according to the stress state in every slice.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001813331
|
oai_dc
|
Prediction model for the hydration properties of concrete
|
Prediction model for the hydration properties of concrete
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"추인엽(삼성엔지니어링); Muhammad Nasir Amin(한국과학기술대학교); 김진근(한국과학기술원)"
] |
This paper investigates prediction models estimating the hydration properties of concrete, such as the compressive strength, the splitting tensile strength, the elastic modulus,and the autogenous shrinkage. A prediction model is suggested on the basis of an equation that is formulated to predict the compressive strength. Based on the assumption that the apparent activation energy is a characteristic property of concrete, a prediction model for the compressive strength is applied to hydration-related properties. The hydration properties predicted by the model are compared with experimental results, and it is concluded that the prediction model properly estimates the splitting tensile strength, elastic modulus, and autogenous shrinkage as well as the compressive strength of concrete.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001813342
|
oai_dc
|
Equifield line simulation and ion migration prediction for concrete under 2-D electric field
|
Equifield line simulation and ion migration prediction for concrete under 2-D electric field
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chih-Chien Liu(ROC Military Academy); Chun-Yao Huang(National Kaohsiung University of Applied); Wen-Ten Kuo(National Kaohsiung University of Applied)"
] |
This study attempted to find a proper method applicable to simulating practical equifield lines of two-dimensional Accelerate Lithium Migration Technique (ALMT), and evaluate the feasibility of using the theoretical ion migration model of one-dimensional ALMT to predict the ion migration behavior of two-dimensional ALMT. The result showed that the electrolyte or carbon plate can be used as matrix to draw equifield line graph similar to that by using mortar as matrix. Using electrolyte electrode module for simulation has advantages of simple production, easy measurement, rapidness, and economy. The electrolyte module can be used to simulate the equifield line distribution diagram in practical two-dimensional electrode configuration firstly. Then, several equifield line zones were marked, and several subzones under one-dimensional ALMT were separated from various equifield line zones. The theoretical free content distribution of alkali in concrete under two-dimensional electric field effect could be obtained from duration analysis.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001813365
|
oai_dc
|
On modeling coupling beams incorporating strain-hardening cement-based composites
|
On modeling coupling beams incorporating strain-hardening cement-based composites
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chung-Chan Hung(National Central University); Yen-Fang Su(National Central University)"
] |
Existing numerical models for strain-hardening cement-based composites (SHCC) are short of providing sufficiently accurate solutions to the failure patterns of coupling beams of different designs. The objective of this study is to develop an effective model that is capable of simulating the nonlinear behavior of SHCC coupling beams subjected to cyclic loading. The beam model proposed in this study is a macro-scale plane stress model. The effects of cracks on the macro-scale behavior of SHCC coupling beams are smeared in an anisotropic model. In particular, the influence of the defined crack orientations on the simulation accuracy is explored. Extensive experimental data from coupling beams with different failure patterns are employed to evaluate the validity of the proposed SHCC coupling beam models. The results show that the use of the suggested shear stiffness retention factor for damaged SHCC coupling beams is able to effectively enhance the simulation accuracy, especially for shear-critical SHCC coupling beams. In addition, the definition of crack orientation for damaged coupling beams is found to be a critical factor influencing the simulation accuracy.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001813337
|
oai_dc
|
Nonlinear finite element modeling of FRP-wrapped UHPC columns
|
Nonlinear finite element modeling of FRP-wrapped UHPC columns
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Soner Guler(Istanbul Technical University); Alperen Çopur(Istanbul Technical University); Metin Aydogan(Istanbul Technical University)"
] |
The primary aim of this study is to develop a three dimensional finite element (FE) model to predict the axial stress-strain relationship and ultimate strength of the FRP-wrapped UHPC columns by comparing experimental results. The reliability of four selected confinement models and three design codes such as ACI-440, CSA-S806-02, and ISIS CANADA is also evaluated in terms of agreement with the experimental results. Totally 6 unconfined and 36 different types of the FRP-wrapped UHPC columns are tested under monotonic axial compression. The values of ultimate strengths of FRP-wrapped UHPC columns obtained from the experimental results are compared and verified with finite element (FE) analysis results and the design codes mentioned above. The concrete damage plasticity model (CDPM) in Abaqus is utilized to represent the confined behavior of the UHPC. The results indicate that agreement between the test results and the non-linear FE analysis results is highly satisfactory. The CSA-S806-02 design code is considered more reliable than the ACI-440 and the ISIS CANADA design codes to calculate the ultimate strength of the FRP-wrapped UHPC columns. None of the selected confinement models that are developed for FRP-wrapped low and normal strength concrete columns can safely predict the ultimate strength of FRP-wrapped UHPC columns.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001813335
|
oai_dc
|
Influence of shear deformation of exterior beam-column joints on the quasi-static behavior of RC framed structures
|
Influence of shear deformation of exterior beam-column joints on the quasi-static behavior of RC framed structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ricardo J.T. Costa(University of Coimbra); Fernando C.T. Gomes(ESTGOH); Paulo M.M.P. Providência(Rua Antero de Quental 199); Alfredo M.P.G. Dias(University of Coimbra)"
] |
In the analysis and design of reinforced concrete frames beam-column joints are sometimes assumed as rigid. This simplifying assumption can be unsafe because it is likely to affect the distributions of internal forces and moments, reduce drift and increase the overall load-carrying capacity of the frame. This study is concerned with the relevance of shear deformation of beam-column joints, in particular of exterior ones, on the quasi-static behavior of regular reinforced concrete sway frames. The included parametric studies of a simple sub-frame model reveal that the quasi-static monotonic behavior of unbraced regular reinforced concrete frames is prone to be significantly affected by the deformation of beam-column joints.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001813346
|
oai_dc
|
Computationally efficient 3D finite element modeling of RC structures
|
Computationally efficient 3D finite element modeling of RC structures
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"George Markou(Alhosn University); Manolis Papadrakakis(National Technical University of Athens)"
] |
A detailed finite element modeling is presented for the simulation of the nonlinear behavior of reinforced concrete structures which manages to predict the nonlinear behavior of four different experimental setups with computational efficiency, robustness and accuracy. The proposed modeling method uses 8-node hexahedral isoparametric elements for the discretization of concrete. Steel rebars may have any orientation inside the solid concrete elements allowing the simulation of longitudinal as well as transverse reinforcement. Concrete cracking is treated with the smeared crack approach, while steel reinforcement is modeled with the natural beam-column flexibility-based element that takes into consideration shear and bending stiffness. The performance of the proposed modeling is demonstrated by comparing the numerical predictions with existing experimental and numerical results in the literature as well as with those of a commercial code. The results show that the proposed refined simulation predicts accurately the nonlinear inelastic behavior of reinforced concrete structures achieving numerical robustness and computational efficiency.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001813351
|
oai_dc
|
Flexural ductility of RC beam sections at high strain rates
|
Flexural ductility of RC beam sections at high strain rates
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Akhilesh K. Pandey(CSIR-Central Building Research Institute)"
] |
Computation of flexural ductility of reinforced concrete beam sections has been proposed by taking into account strain rate sensitive constitutive behavior of concrete and steel, confinement of core concrete and degradation of cover concrete during load reversal under earthquake loading. The estimate of flexural ductility of reinforced concrete rectangular sections has been made for a wide range of tension and compression steel ratios for confined and unconfined concrete at a strain rate varying from 3.3 × 10-5 to 1.0/sec encountered during normal and earthquake loading. The parametric studies indicated that flexural ductility factor decreases at increasing strain rates. Percentage decrease is more for a richer mix concrete with the similar reinforcement. The confinement effect has marked influence on flexural ductility and increase in ductility is more than twice for confined concrete (0.6 percent volumetric ratio of transverse steel) compared to unconfined concrete. The provisions in various codes for achieving ductility in moment resisting frames have been discussed.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001813364
|
oai_dc
|
Replicating the chemical composition of the binder for restoration of historic mortars as an optimization problem
|
Replicating the chemical composition of the binder for restoration of historic mortars as an optimization problem
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"D. Miriello(Università della Calabria); M. Lezzerini(Università di Pisa); F. Chiaravalloti(Università della Calabria); A. Bloise(Università della Calabria); C. Apollaro(Università della Calabria); G.M. Crisci(Università della Calabria)"
] |
The present study aims to show how the problem of reproducing, as closely as possible, binders of historic mortars by mixing raw materials which are commercially available, can be formulated as a linear optimization problem. The study points out that by mixing five standard raw materials (end-members) it is possible to obtain mortar binders with the almost same chemical compositions of those determined on the historic and archaeological mortar samples studied in some recent scientific papers. An advanced function of the Microsoft Excel spreadsheet, the Solver add-in, was used for the calculation of the right amount of each raw material to be mixed for producing the new binders. This approach could be useful to provide an optimal solution in the process of restoration of ancient monuments, where it is necessary to replace the historic mortars with new highly compatible repair mortars.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001813347
|
oai_dc
|
An efficient method for the compressive behavior of FRP-confined concrete cylinders
|
An efficient method for the compressive behavior of FRP-confined concrete cylinders
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Xinglang Fan(Dalian University of Technology); Zhimin Wu(Dalian University of Technology); Yufei Wu(City University of Hong Kong); Jianjun Zheng(Zhejiang University of Technology)"
] |
Fiber reinforced polymer (FRP) jackets have been widely used as an effective tool for the strengthening and rehabilitation of concrete structures, especially damaged concrete columns. Therefore, a clear understanding of the compressive behavior of FRP-confined concrete is essential. The objective of this paper is to develop a simple efficient method for predicting the compressive strength, the axial strain at the peak stress, and the stress-strain relationship of FRP-confined concrete. In this method, a compressive strength model is established based on Jefferson’s failure surface. With the proposed strength model, the strength of FRP-confined concrete can be estimated more precisely. The axial strain at the peak stress is then evaluated using a damage-based formula. Finally, a modified stress-strain relationship is derived based on Lam and Teng’s model. The validity of the proposed compressive strength and strain models and the modified stress-strain relationship is verified with a wide range of experimental results collected from the research literature and obtained from the self-conducted test. It can be concluded that, as a competitive alternative, the proposed method can be used to predict the compressive behavior of FRP-confined concrete with reasonable accuracy.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001813349
|
oai_dc
|
Analysis of RC walls with a mixed formulation frame finite element
|
Analysis of RC walls with a mixed formulation frame finite element
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Afsin Saritas(Middle East Technical University); Filip C. Filippou(University of California)"
] |
This paper presents a mixed formulation frame element with the assumptions of the Timoshenko shear beam theory for displacement field and that accounts for interaction between shear and normal stress at material level. Nonlinear response of the element is obtained by integration of section response, which in turn is obtained by integration of material response. Satisfaction of transverse equilibrium equations at section includes the interaction between concrete and transverse reinforcing steel. A 3d plastic damage model is implemented to describe the hysteretic behavior of concrete. Comparisons with available experimental data on RC structural walls confirm the accuracy of proposed method.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001803374
|
oai_dc
|
Applications of the ANFIS and LR in the prediction of strain in tie section of concrete deep beams
|
Applications of the ANFIS and LR in the prediction of strain in tie section of concrete deep beams
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mohammad Mohammadhassani(University of Malaya); Hossein Nezamabadi-Pour(Shahid Bahonar University of Kerman); Mohammed Jameel(University of Malaya); Karim Garmasiri(Razi University)"
] |
Recent developments in Artificial Intelligence (AI) and computational intelligence have made it viable in the construction industry and structural analysis. This study usesthe Adaptive Network-based Fuzzy Inference System (ANFIS) as a modelling tool to predict the strain in tie section for High Strength Self Compacting Concrete (HSSCC) deep beams. 3773 experimental data were collected. The input data andits corresponding strains in tie section as output data were recorded at all loading stages. Results from ANFIS are compared with the classical linear regression (LR). The comparison shows that the ANFIS‘s results are highly accurate, precise and satisfactory.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001803383
|
oai_dc
|
A study on electrical and thermal properties of conductive concrete
|
A study on electrical and thermal properties of conductive concrete
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Tehsien Wu(National Taiwan Ocean University); Ran Huang(National Taiwan Ocean University); Maochieh Chi(Wufeng University); Tsailung Weng(Tatung University)"
] |
Traditional concrete is effectively an insulator in the dry state. However, conductive concrete can attain relatively high conductivity by adding a certain amount of electronically conductive components in the regular concrete matrix. The main purpose of this study is to investigate the electrical and thermal properties of conductive concrete with various graphite contents, specimen dimensions and applied voltages. For this purpose, six different mixtures (the control mixtures and five conductive mixtures with steel fibers of 2% by weight of coarse aggregate and graphite as fine aggregate replacement at the levels of 0%, 5%, 10%, 15% and 20% by weight) were prepared and concrete blocks with two types of dimensions were fabricated. Four test voltage levels, 48 V, 60 V, 110 V, and 220 V, were applied for the electrical and thermal tests. Test results show that the compressive strength of specimens decreases as the amount of graphite increases in concrete. The rising applied voltage decreases electrical resistivity and increases heat of concrete. Meanwhile, higher electrical current and temperature have been obtained in small size specimens than the comparable large size specimens. From the results, it can be concluded that the graphite contents, applied voltage levels, and the specimen dimensions play important roles in electrical and thermal properties of concrete. In addition, the superior electrical and thermal properties have been obtained in the mixture adding 2% steel fibers and 10% graphite.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001803378
|
oai_dc
|
Predicting the indirect tensile strength of self-compacting concrete using artificial neural networks
|
Predicting the indirect tensile strength of self-compacting concrete using artificial neural networks
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Moosa Mazloom(Shahid Rajaee Teacher Training University); M.M. Yoosefi(Shahid Rajaee Teacher Training Universit)"
] |
This paper concentrates on the results of experimental work on tensile strength of self-compacting concrete (SCC) caused by flexure, which is called rupture modulus. The work focused on concrete mixes having water/binder ratios of 0.35 and 0.45, which contained constant total binder contents of 500 kg/m3 and 400 kg/m3, respectively. The concrete mixes had four different dosages of a superplasticizer based on polycarboxylic with and without silica fume. The percentage of silica fume that replaced cement in this research was 10%. Based upon the experimental results, the existing equations for anticipating the rupture modulus of SCC according to its compressive strength were not exact enough. Therefore, it is decided to use artificial neural networks (ANN) for anticipating the rupture modulus of SCC from its compressive strength and workability. The conclusion was that the multi layer perceptron (MLP) networks could predict the tensile strength in all conditions, but radial basis (RB) networks were not exact enough in some circumstances. On the other hand, RB networks were more users friendly and they converged to the final networks quicker.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001803379
|
oai_dc
|
Composed material models for nonlinear behavior of reinforced concrete
|
Composed material models for nonlinear behavior of reinforced concrete
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Tayfun Dede(Karadeniz Technical University); Yusuf Ayvaz(Karadeniz Technical University)"
] |
The purpose of this study is to present different composed material models for reinforced concrete structures (RC). For this aim a nonlinear finite element analysis program is coded in MATLAB.
This program contains several yield criteria and stress-strain relationships for compression and tension behavior of concrete. In this study, the well-known criteria, Drucker-Prager, von Mises, Mohr Coulomb, Tresca, and two new criteria, Hsieh-Ting-Chen and Bresler-Pister, are taken into account. It is concluded that the coded program, the new yield criteria, and the models considered can be effectively used in the nonlinear analysis of reinforced concrete beams.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001803384
|
oai_dc
|
Progressive collapse resistance of flat slabs: modeling post-punching behavior
|
Progressive collapse resistance of flat slabs: modeling post-punching behavior
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yaser Mirzaei(Northeastern University); Mehrdad Sasani(Northeastern University)"
] |
Post-punching resistance of a flat slab can help redistribute the gravity loads and resist progressive collapse of a structure following initial damage. One important difficulty with accounting for the post-punching strength of a slab is the discontinuity that develops following punching shear. A numerical simulation technique is proposed here to model and evaluate post-punching resistance of flat slabs. It is demonstrated that the simulation results of punching shear and post-punching response of the model of a slab on a single column are in good agreement with corresponding experimental data. It is also shown that progressive collapse due to a column removal (explosion) can lead to punching failure over an adjacent column. Such failure can propagate throughout the structure leading to the progressive collapse of the structure. Through post-punching modeling of the slab and accounting for the associated discontinuity, it is also demonstrated that the presence of an adequate amount of integrity reinforcement can provide an alternative load path and help resist progressive collapse.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001803381
|
oai_dc
|
Experimental and numerical analysis of new bricks made up of polymer modified-cement using expanded vermiculite
|
Experimental and numerical analysis of new bricks made up of polymer modified-cement using expanded vermiculite
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Fuat Köksal(Bozok University); Juan J. del Coz Diaz(University of Oviedo); Osman Gencel(Bartin University,); Felipe P. Alvarez Rabanal(University of Oviedo)"
] |
In this paper, the properties of the cement mortar modified with styrene acrylic ester copolymer were investigated. Expanded vermiculite as lightweight aggregate was used for making the polymer modified mortar test specimens. To study the effect of polymer–cement ratio and vermiculite-cement ratio on various properties, specimens were prepared by varying the polymer–cement and vermiculite-cement ratios. Tests of physical properties such as density, water absorption, thermal conductivity, three-point flexure and compressive tests were made on the specimens. Furthermore, a coupled thermal-structural finite element model of an entire corner wall was modelled in order to study the best material configuration. The wall is composed by a total of 132 bricks of 120 × 242 × 54 size, joined by means of a contact-bonded model. The use of advanced numerical methods allows us to obtain the optimum material properties. Finally, comparisons of polymer–cement and vermiculite-cement ratios on physical properties are given and the most important conclusions are exposed.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001803375
|
oai_dc
|
A local-global scheme for tracking crack path in three-dimensional solids
|
A local-global scheme for tracking crack path in three-dimensional solids
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"O. L. Manzoli(Sao Paulo State University (UNESP)); G.K.S. Claro(Sao Paulo State University (UNESP)); J.A. Lopes Jr.(Sao Paulo State University (UNESP))"
] |
This paper aims to contribute to the three-dimensional generalization of numerical prediction of crack propagation through the formulation of finite elements with embedded discontinuities. The analysis of crack propagation in two-dimensional problems yields lines of discontinuity that can be tracked in a relatively simple way through the sequential construction of straight line segments oriented according to the direction of failure within each finite element in the solid. In three-dimensional analysis, the construction of the discontinuity path is more complex because it requires the creation of plane surfaces within each element, which must be continuous between the elements. In the method proposed by Chaves (2003) the crack is determined by solving a problem analogous to the heat conduction problem, established from local failure orientations, based on the stress state of the mechanical problem. To minimize the computational effort, in this paper a new strategy is proposed whereby the analysis for tracking the discontinuity path is restricted to the domain formed by some elements near the crack surface that develops along the loading process. The proposed methodology is validated by performing three-dimensional analyses of basic problems of experimental fractures and comparing their results with those reported in the literature.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001667019
|
oai_dc
|
Structural behaviour of tapered concrete-filled steel composite (TCFSC) columns subjected to eccentric loading
|
Structural behaviour of tapered concrete-filled steel composite (TCFSC) columns subjected to eccentric loading
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Alireza Bahrami(Universiti Kebangsaan Malaysia); Wan Hamidon Wan Badaruzzaman(Universiti Kebangsaan Malaysia); Siti Aminah Osman(Universiti Kebangsaan Malaysia)"
] |
This paper deals with the structural behaviour of tapered concrete-filled steel composite (TCFSC) columns under eccentric loading. Finite element software LUSAS is used to perform the nonlinear analyses to predict the structural behaviour of the columns. Results from the finite element modelling and existing experimental test are compared to verify the accuracy of the modelling. It is demonstrated that they correlate reasonably well with each other; therefore, the proposed finite element modelling is absolutely accurate to predict the structural behaviour of the columns. Nonlinear analyses are carried out to investigate the behaviour of the columns where the main parameters are: (1) tapered angle (from 0o to 2.75o); (2) steel wall thickness (from 3 mm to 4 mm); (3) load eccentricity (15 mm and 30 mm); (4) L/H ratio (from 10.67 to 17.33); (5) concrete compressive strength (from 30 MPa to 60 MPa); (6) steel yield stress (from 250 MPa to 495 MPa). Results are depicted in the form of load versus mid-height deflection plots. Effects of various tapered angles, steel wall thicknesses, and L/H ratios on the ultimate load capacity, ductility and stiffness of the columns are studied. Effects of different load eccentricities, concrete compressive strengths and steel yield stresses on the ultimate load capacity of the columns are also examined. It is concluded from the study that the parameters considerably influence the structural behaviour of the columns.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000097.xml
|
||
ART001667023
|
oai_dc
|
Effect of polyolefin fibers on the permeability of cement-based composites
|
Effect of polyolefin fibers on the permeability of cement-based composites
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hui-Mi Hsu(National Ilan University); Wei-Ting Lin(National Ilan University); An Cheng(National Ilan University)"
] |
This study evaluates the permeability of cement-based composites, which are a mix of polyolefin fibers and silica fume. Test results indicate that permeability increases as the water/cementitious ratio increases. Silica fume in cement-based composites produced hydrated calcium silicate and filled the pores. However, permeability decreased as the addition of silica fume increased. Specimens containing polyolefin fibers also provided higher permeability resistance. The polyolefin fiber length did not have a significant effect on permeability. The decrease in the permeability is mainly due to the addition of silica fume and lower water/cementitious ratio. Addition of fibers marginally decreases the permeability. Incorporating polyolefin fiber and silica fume in composites achieved more significant decreases in permeability. The correlated test results reveal the interrelationship between them.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000097.xml
|
||
ART001667021
|
oai_dc
|
An investigation on plan geometries of RC buildings: with or without projections in plan
|
An investigation on plan geometries of RC buildings: with or without projections in plan
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Tugba Inan(Izmir Institute of Technology); Koray Korkmaz(Izmir Institute of Technology); Ismail H. Cagatay(Cukurova University)"
] |
The interaction of plan geometry and structural configuration, a determinative factor in the earthquake behavior of buildings, has become a serious issue in the building industry in Turkey due to the poor seismic performance of R/C buildings during the latest earthquake. Consequently, designing new buildings without structural irregularities against earthquake loads is proving to be more significant. This study focuses on the effects of plan geometries on earthquake performances of buildings. In that respect, structural irregularities in the plan are investigated in detail based on the Turkish Earthquake Code (TEC 2007). The study is based on five main parametric models and a total of 40 sub-models that are grouped according to their plan geometries with excessive projections such as L-shaped, H-shaped, T-shaped and U-shaped models. In addition to these, a square model without any projections is also generated. All models are designed to have the same storey gross area but with different number of storeys. Changes in the earthquake behavior of buildings were evaluated according to the number of storeys, the projection ratios and the symmetry conditions of each model. The analysis of each structural irregularity resulted in many findings, which were then assessed. The study demonstrates that the square model delivers the best earthquake performance owing to its regular plan geometry.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000097.xml
|
||
ART001667024
|
oai_dc
|
Neuro-Fuzzy modeling of torsional strength of RC beams
|
Neuro-Fuzzy modeling of torsional strength of RC beams
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A. Cevik(University Of Gaziantep); R. Saracoglu(Selcuk University); M.H. Arslan(Selcuk University)"
] |
This paper presents Neuro-Fuzzy (NF) based empirical modelling of torsional strength of RC beams for the first time in literature. The proposed model is based on fuzzy rules. The experimental database used for NF modelling is collected from the literature consisting of 76 RC beam tests. The input variables in the developed rule based on NF model are cross-sectional area of beams, dimensions of closed stirrups, spacing of stirrups, cross-sectional area of one-leg of closed stirrup, yield strength of stirrup and longitudinal reinforcement, steel ratio of stirrups, steel ratio of longitudinal reinforcement and concrete compressive strength. According to the selected variables, the formulated NFs were trained by using 60 of the 76 sample beams. Then, the method was tested with the other 16 sample beams. The accuracy rates were found to be about 96% for total set. The performance of accuracy of proposed NF model is furthermore compared with existing design codes by using the same database and found to be by far more accurate. The use of NF provided an alternative way for estimating the torsional strength of RC beams. The outcomes of this study are quite satisfactory which may serve NF approach to be widely used in further applications in the field of reinforced concrete structures.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000097.xml
|
||
ART001667020
|
oai_dc
|
The effects of replacement fly ash with diatomite in geopolymer mortar
|
The effects of replacement fly ash with diatomite in geopolymer mortar
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Theerawat Sinsiri(Suranaree University of Technology); Tanakorn Phoo-ngernkham(Suranaree University of Technology); Vanchai Sata(Khon Kaen University); Prinya Chindaprasirt(Khon Kaen University)"
] |
This article presents the effect of replacement fly ash (FA) with diatomite (DE) on the properties of geopolymer mortars. DE was used to partially replace FA at the levels of 0, 60, 80 and 100% by weight of binder. Sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) solutions were used as the liquid portion in the mixture in order to activate the geopolymerization. The NaOH concentrations of 15M, Na2SiO3/NaOH ratios of 1.5 by weight, and the alkaline liquid/binder (LB) ratios by weight of 0.40, 0.50, 0.60 and 0.70 were used. The curing at temperature of 75oC for 24 h was used to accelerate the geopolymerization. The flows of all fresh geopolymer mortars were tested. The compressive strengths and the stress-strain characteristics of the mortar at the age of 7 days, and the unit weights were also tested. The results revealed that the use of DE to replace part of FA as source material in making geopolymer mortars resulted in the increased in the workability, and strain capacity of mortar specimens and in the reductions in the unit weights and compressive strengths. The strain capacity of the mortar increased from 0.0028 to 0.0150 with the increase in the DE replacement levels from 0 to 100%. The mixes with 15M NaOH, Na2SiO3/NaOH of 1.5, LB ratio of 0.50, and using 75oC curing temperature showed 7 days compressive strengths 22.0-81.0 MPa which are in the range of normal to high strength mortars.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000097.xml
|
||
ART001642913
|
oai_dc
|
The high-rate brittle microplane concrete model: Part I: bounding curves and quasi-static fit to material property data
|
The high-rate brittle microplane concrete model: Part I: bounding curves and quasi-static fit to material property data
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mark D. Adley(U.S. Army Engineer Research and Development Center); Andreas O. Frank(U.S. Army Engineer Research and Development Center); Kent T. Danielson(U.S. Army Engineer Research and Development Center)"
] |
This paper discusses a new constitutive model called the high-rate brittle microplane (HRBM) model and also presents the details of a new software package called the Virtual Materials Laboratory (VML). The VML software package was developed to address the challenges of fitting complex material models such as the HRBM model to material property test data and to study the behavior of those models under a wide variety of stress- and strain-paths. VML employs Continuous Evolutionary Algorithms (CEA) in conjunction with gradient search methods to create automatic fitting algorithms to determine constitutive model parameters. The VML code is used to fit the new HRBM model to a well-characterized conventional strength concrete called WES5000. Finally, the ability of the new HRBM model to provide high-fidelity simulations of material property experiments is demonstrated by comparing HRBM simulations to laboratory material property data.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001642911
|
oai_dc
|
The 3D-numerical simulation on failure process of concrete-filled tubular (CFT) stub columns under uniaxial compression
|
The 3D-numerical simulation on failure process of concrete-filled tubular (CFT) stub columns under uniaxial compression
|
{
"journal_name": "사단법인 한국계산역학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"W.C. Zhu(Northeastern University); L. Ling(Northeastern University); C.A. Tang(Dalian University of Technology); Y.M. Kang(Northeastern University); xielinmao(서울대학교)"
] |
Based on the heterogeneous characterization of concrete at mesoscopic level, Realistic Failure Process Analysis (RFPA3D) code is used to simulate the failure process of concrete-filled tubular (CFT) stub columns. The results obtained from the numerical simulations are firstly verified against the existing experimental results. An extensive parametric study is conducted to investigate the effects of different concrete strength on the behaviour and load-bearing capacity of the CFT stub columns. The strength of concrete considered in this study ranges from 30 to 110 MPa. Both the load-bearing capacity and loaddisplacement curves of CFT columns are evaluated. In particular, the crack propagation during the deformation and failure processes of the columns is predicted and the associated mechanisms related to the increased load-bearing capacity of the columns are clarified. The numerical results indicate that there are two mechanisms controlling the failure of the CFT columns. For the CFT columns with the lower concrete strength, they damage when the steel tube yields at first. By contrast, for the columns with high concrete strength it is the damage of concrete that controls the overall loading capacity of the CFT columns. The simulation results also demonstrate that RFPA3D is not only a useful and effective tool to simulate the concrete-filled steel tubular columns, but also a valuable reference for the practice of engineering design.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001642912
|
oai_dc
|
Importance of a rigorous evaluation of the cracking moment in RC beams and slabs
|
Importance of a rigorous evaluation of the cracking moment in RC beams and slabs
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A.V. Lopes(University of Coimbra); S.M.R. Lopes(University of Coimbra)"
] |
The service loads are often decisive in the design of concrete structures. The evaluation of the cracking moment, Mcr, is an important issue to predict the performance of the structure, such as, the deflections of the reinforced concrete beams and slabs. To neglect the steel bars of the section is a simplification that is normally used in the computation of the cracking moment. Such simplification leads to small errors in the value of this moment (typically less than 20%). However, these small errors can conduce to significant errors when the values of deflections need to be computed from Mcr. The article shows that an error of 10% on the evaluation of Mcr can lead to errors over 100% in the deformation values. When the deformation of the structure is the decisive design parameter, the exact computing of the cracking moment is obviously very important. Such rigorous computing might lead to important savings in the cost of the structure. With this article the authors wish to draw the attention of the technical community to this fact. A simple equation to evaluate the cracking moment, Mcr, is proposed for a rectangular crosssection. This equation leads to cracking moments higher than those obtained by neglecting the reinforcement bars and is a simple rule that can be included in Eurocode 2. To verify the accuracy of the developed model, the results of the proposed equation was compared with a rigorous computational procedure. The proposed equation corresponds to a good agreement when compared with the previous approach and, therefore, this model can be used as a practical aid for calculating an accurate value of the cracking moment.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001642910
|
oai_dc
|
Simulation of the damping effect of a high-rise CRST frame structure
|
Simulation of the damping effect of a high-rise CRST frame structure
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Xilin Lu(Tongji University); Chunguang Meng(Tongji University); Hongmei Zhang(Tongji University)"
] |
The damping effect of a Concrete-filled Rectangular Steel Tube (CRST) frame structure is studied in this paper. Viscous dampers are employed to insure the function of the building especially subjected to earthquakes, for some of the main vertical elements of the building are not continuous. The shaking table test of a 1:15 scale model was conducted under different earthquake excitations to recognize the seismic behavior of this building. And the vibration damping effect was also investigated by the shaking table test and the simulation analysis. The nonlinear time-history analysis of the shaking table test model was carried out by the finite element analysis program CANNY. The simulation model was constructed in accordance with the tested one and was analyzed under the same loading condition and the simulation effect was then validated by the tested results. Further more, the simulation analysis of the prototype structure was carried out by the same procedure. Both the simulated and tested results indicate that there are no obvious weak stories on the damping equipped structure, and the dampers can provide the probability of an irregular CRST frame structure to meet the requirements of the design code on energy dissipation and deformation limitation.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001643309
|
oai_dc
|
The high-rate brittle microplane concrete model: Part II: application to projectile perforation of concrete slabs
|
The high-rate brittle microplane concrete model: Part II: application to projectile perforation of concrete slabs
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Andreas O. Frank(U.S. Army Engineer Research and Development Center Impact and Explosive Effects Branch); Mark D. Adley(U.S. Army Engineer Research and Development Center Impact and Explosive Effects Branch); Kent T. Danielson(U.S. Army Engineer Research and Development Center Impact and Explosive Effects Branch); Henry S. McDevitt, Jr.(U.S. Army Engineer Research and Development Center Impact and xplosive Effects Branch)"
] |
In this paper, we examine the behavior of the High-Rate Brittle Microplane (HRBM) concrete model based on a series of penetration experiments. These experiments were conducted with three different slab thicknesses (127, 216 and 254 mm) that provided a significant challenge for the numerical simulations. The 127 mm slab provided little resistance, the 216 mm slab provided nominal resistance and the 254 mm slab approached the perforation limit thickness of the projectile. These experiments provide a good baseline for evaluating material models since they have been shown to be extremely challenging; in fact, we have not encountered many material models that can provide quantitatively predictive results in terms of both projectile exit velocity and material damage. In a companion paper, we described the HRBM material model and its fit to various quasi-static material property data for WES-5000 concrete. In this paper, we show that, when adequately fit to these quasi-static data, the HRBM model does not have significant predictive capabilities, even though the quasi-static material fit may be exceptional. This was attributed to the rate-dependent response of the material. After various rate effects were introduced into the HRBM model, the quantitative predictive nature of the calculations dramatically increased. Unfortunately, not much rate-dependent material property data are in the literature; hence, accurate incorporation of rate effects into material models is difficult. Nonetheless, it seems that rate effects may be critical in obtaining an accurate response for concrete during projectile perforation events.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001632252
|
oai_dc
|
Generalization of shear truss model to the case of SFRC beams with stirrups
|
Generalization of shear truss model to the case of SFRC beams with stirrups
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Piero Colajanni(University of Messina); Antonino Recupero(University of Messina); Nino Spinella(University of Messina)"
] |
A theoretical model for shear strength evaluation of fibrous concrete beams reinforced with stirrups is proposed. The formulation is founded on the theory of plasticity and the stress field concepts, generalizing a known plastic model for calculating the bearing capacity of reinforced concrete beams, to the case of fibrous concrete. The beneficial effect of steel fibres is estimated taking into account the residual tensile strength of fibrous concrete, by modifying an analytical constitutive law which presents a plastic plateau as a post-peak branch. Around fifty results of experimental tests carried out on steel fibrous concrete beams available in the literature were collected, and a comparison of shear strength estimation provided by other semi-empirical models is performed, proving that the numerical values obtained with the proposed model are in very good agreement with the experimental results.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001632250
|
oai_dc
|
Investigation of effectiveness of double concave friction pendulum bearings
|
Investigation of effectiveness of double concave friction pendulum bearings
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Sevket Ates(Karadeniz Technical University)"
] |
This paper presents the investigation of the stochastic responses of seismically isolated bridges subjected to spatially varying earthquake ground motions including incoherence, wave-passage and site-response effects. The incoherence effect is examined by considering Harichandran and Vanmarcke coherency model. The effect of the wave-passage is dealt with various wave velocities in the response analysis. Homogeneous firm, medium and soft soil conditions are selected for considering the siteresponse effect where the bridge supports are constructed. The ground motion is described by filtered white noise and applied to each support points. For seismic isolation of the bridge, single and double concave friction pendulum bearings are used. Due to presence of friction on the concave surfaces of the isolation systems, the equation of motion of is non-linear. The non-linear equation of motion is solved by using equivalent linearization technique of non-linear stochastic analyses. Solutions obtained from the stochastic analyses of non-isolated and isolated bridges to spatially varying earthquake ground motions compared with each other for the special cases of the ground motion model. It is concluded that friction pendulum systems having single and double concave surfaces have important effects on the stochastic responses of bridges to spatially varying earthquake ground motions.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001632248
|
oai_dc
|
Modeling of fiber pullout behaviors of stiff fiber reinforced cementitious composites
|
Modeling of fiber pullout behaviors of stiff fiber reinforced cementitious composites
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Xu Chang(Henan Polytechnic University); Ya-Juan Chen(Henan Polytechnic University); Hai-Xiao Lin(Henan Polytechnic University); Yong-bin Zhang(Dalian University of Technology)"
] |
This paper presents numerical studies of stiff fiber pullout behaviors of fiber reinforced cementitious composites based on a progressive damage model. The ongoing debonding process is simulated. Interfacial stress distribution for different load levels is analyzed. A parametric study, including bond strength and the homogeneity index on the pullout behaviors is carried out. The numerical results indicate that the bond stress decreases gradually from loaded end to embedded end along fiber-cement interface. The debonding initially starts from loaded end and propagates to embedded end as load increasing. The embedded length and bond strength affect the load-loaded end displacement curves significantly. The numerical results have a general agreement with the experimental investigation.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001632251
|
oai_dc
|
Utilization of support vector machine for prediction of fracture parameters of concrete
|
Utilization of support vector machine for prediction of fracture parameters of concrete
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Pijush Samui(Centre for Disaster Mitigation and Management, VIT University); 김두기(군산대학교)"
] |
This article employs Support Vector Machine (SVM) for determination of fracture parameters critical stress intensity factor (Ksic) and the critical crack tip opening displacement (CTODc) of concrete. SVM that is firmly based on the theory of statistical learning theory, uses regression technique by introducing ε-insensitive loss function has been adopted. The results are compared with a widely used Artificial Neural Network (ANN) model. Equations have been also developed for prediction of Ksic and CTODc. A sensitivity analysis has been also performed to investigate the importance of the input parameters. The results of this study show that the developed SVM is a robust model for determination of Ksic and CTODc of concrete.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001632249
|
oai_dc
|
Model for simulating the effects of particle size distribution on the hydration process of cement
|
Model for simulating the effects of particle size distribution on the hydration process of cement
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Changjiu Chen(Tsinghua University); Xuehui An(Tsinghua University)"
] |
The hydration of cement contributes to the performance characteristics of concrete, such as strength and durability. In order to improve the utilization efficiency of cement and its early properties, the particle size distribution (PSD) of cement varies considerably, and the effects of the particle size distribution of cement on the hydration process should be considered. In order to evaluate effects of PSD separately, experiments testing the isothermal heat generated during the hydration of cements with different particle size distributions but the same chemical composition have been carried out. The measurable hydration depth for cement hydration was proposed and deduced based on the experimental results, and a PSD hydration model was developed in this paper for simulating the effects of particle size distribution on the hydration process of cement. First, a reference hydration rate was derived from the isothermal heat generated by the hydration of ordinary Portland cement. Then, the model was extended to take into account the effect of water-to-cement ratio, hereinafter which was referred to as PSD hydration model. Finally, the PSD hydration model was applied to simulate experiments measuring the isothermal heat generated by the hydration of cement with different particle size distributions at different water-to-cement ratios. This showed that the PSD hydration model had simulated the effects of particle size distribution and water-to-cement ratio on the hydration process of cement with satisfactory accuracy.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001682530
|
oai_dc
|
Analytical simulation of reversed cyclic lateral behaviors of an RC shear wall sub-assemblage
|
Analytical simulation of reversed cyclic lateral behaviors of an RC shear wall sub-assemblage
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"이한선(고려대학교); Da Hun Jeong(Korea University); 황경란(고려대학교)"
] |
Experimental results of cyclic reversed lateral force test on a two-story reinforced concrete shear wall sub-assemblage are simulated analytically by using the PERFORM-3D program. A comparison of experimental and analytical results leads to the following conclusions: (1) “Shear Wall” and “General Wall” models with “Concrete shear” cannot simulate the pinching phenomena due to shear and show larger amounts of inelastic energy absorption than those in the experiment. (2) Modeling a story-height wall by using two or more “General Wall” elements with “Diagonal shear” in the vertical direction induces the phenomenon of swelling-out at the belly, leading to the erroneous simulation of shear behaviors. In application to tall building structures, it is recommended to use one element of “General Wall” with “Diagonal shear” for the full height of a story. (3) In the plastic hinge area, concrete deformations of analytical models overestimate elongation and underestimate shortening when compared with experimental results.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000097.xml
|
||
ART001682531
|
oai_dc
|
Prediction of compressive strength of concrete using neural networks
|
Prediction of compressive strength of concrete using neural networks
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yousef A. Al-Salloum(King Saud University); Abid A. Shah(King Saud University); Saleh H. Alsayed(King Saud University); Tarek H. Almusallam(King Saud University); M.S. Al-Haddad(King Saud University); H. Abbas(King Saud University)"
] |
This research deals with the prediction of compressive strength of normal and high strength concrete using neural networks. The compressive strength was modeled as a function of eight variables: quantities of cement, fine aggregate, coarse aggregate, micro-silica, water and super-plasticizer, maximum size of coarse aggregate, fineness modulus of fine aggregate. Two networks, one using raw variables and another using grouped dimensionless variables were constructed, trained and tested using available experimental data, covering a large range of concrete compressive strengths. The neural network models were compared with regression models. The neural networks based model gave high prediction accuracy and the results demonstrated that the use of neural networks in assessing compressive strength of concrete is both practical and beneficial. The performance of model using the grouped dimensionless variables is better than the prediction using raw variables.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000097.xml
|
||
ART001682523
|
oai_dc
|
Properties of recycled green building materials applied in lightweight aggregate concrete
|
Properties of recycled green building materials applied in lightweight aggregate concrete
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Her-Yung Wang(National Kaohsiung University of Applied Sciences); Darn-Horng Hsiao(National Kaohsiung University of Applied Sciences); Shi-Yang Wang(National Kaohsiung University of Applied Sciences)"
] |
This study uses recycled green building materials based on a Taiwan-made recycled mineral admixture (including fly ash, slag, glass sand and rubber powder) as replacements for fine aggregates in concrete and tests the properties of the resulting mixtures. Fine aggregate contents of 5% and 10% were replaced by waste LCD glass sand and waste tire rubber powder, respectively. According to ACI concretemixture design, the above materials were mixed into lightweight aggregate concrete at a constant water-tobinder ratio (W/B = 0.4). Hardening (mechanical), non-destructive and durability tests were then performed at curing ages of 7, 28, 56 and 91 days and the engineering properties were studied. The results of these experiments showed that, although they vary with the type of recycling green building material added, the slumps of these admixtures meet design requirements. Lightweight aggregate yields better hardened properties than normal-weight concrete, indicating that green building materials can be successfully applied in lightweight aggregate concrete, enabling an increase in the use of green building materials, the improved utilization of waste resources, and environmental protection. In addition to representing an important part of a “sustainable cycle of development”, green building materials represent a beneficial reutilization of waste resources.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000097.xml
|
||
ART001682527
|
oai_dc
|
Reconstruction of internal structures and numerical simulation for concrete composites at mesoscale
|
Reconstruction of internal structures and numerical simulation for concrete composites at mesoscale
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chengbin Du(Hohai University); Wu QIN(CCCC Third Harbor Consultants Co); Hairong Xu(Hohai University); Dong Lei(Hohai University); Shouyan Jiang(Hohai University); 김충호(고려대학교)"
] |
At mesoscale, concrete is considered as a three-phase composite material consisting of the aggregate particles, the cement matrix and the interfacial transition zone (ITZ). The reconstruction of the internal structures for concrete composites requires the identification of the boundary of the aggregate particles and the cement matrix using digital imaging technology followed by post-processing through MATLAB. A parameter study covers the subsection transformation, median filter, and open and close operation of the digital image sample to obtain the optimal parameter for performing the image processing technology. The subsection transformation is performed using a grey histogram of the digital image samples with a threshold value of [120, 210] followed by median filtering with a 16 × 16 square module based on the dimensions of the aggregate particles and their internal impurity. We then select a “disk” tectonic structure with a specific radius, which performs open and close operations on the images. The edges of the aggregate particles (similar to the original digital images) are obtained using the canny edge detection method. The finite element model at mesoscale can be established using the proposed image processing technology. The location of the crack determined through the numerical method is identical to the experimental result, and the load-displacement curve determined through the numerical method is in close agreement with the experimental results. Comparisons of the numerical and experimental results show that the proposed image processing technology is highly effective in reconstructing the internal structures of concrete composites.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000097.xml
|
||
ART001682525
|
oai_dc
|
Software for application of Newton-Raphson method in estimation of strains in prestressed concrete girders
|
Software for application of Newton-Raphson method in estimation of strains in prestressed concrete girders
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Milan Gocic(University of Nis); Enis Sadovic(Ambijent doo)"
] |
Structures suffer from damages in their lifetime due to time-dependant effects, such as fatigue, creep and shrinkage, which can be expressed by concrete strains. These processes could be seen in the context of strain estimation of pre-stressed structures in two phases by using numerical methods. Their aim is checking and validating existing code procedures in determination of deformations of pre-tensioned girders by solving a system of nonlinear equations with strains as unknown parameters. This paper presents an approach based on the Newton-Raphson method for obtaining the stresses and strains in middle span section of pre-stressed girders according the equilibrium state.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000097.xml
|
||
ART001682524
|
oai_dc
|
Flexural performance and fiber distribution of an extruded DFRCC panel
|
Flexural performance and fiber distribution of an extruded DFRCC panel
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"이방연(전남대학교); Byung-Chan Han(Woosong Information College); 조창근(Chosun University); 김윤용(Chungnam National University)"
] |
This paper presents the mix composition and production method that was applied to an extruded Ductile Fiber Reinforced Cement Composite (DFRCC) panel, as well as the flexural performance, represented by deformation hardening behavior with multiple cracking. The effect of fiber distribution characteristics on the flexural behavior of the panel is also addressed. In order to demonstrate the fiber distribution effect, a series of experiments and analyses, including a sectional image analysis and micromechanical analysis, was performed. From the experimental and analysis results, it was found that the flexural behavior of the panel was highly affected by a slight variation in the mix composition. In terms of the average fiber orientation, the fiber distribution was found to be similar to that derived under the assumption of a two-dimensional random distribution, irrespective of the mix composition. In contrast, the probability density function for the fiber orientation was measured to vary depending on the mix composition.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000097.xml
|
||
ART001682528
|
oai_dc
|
Automated design of optimum longitudinal reinforcement for flexural and axial loading
|
Automated design of optimum longitudinal reinforcement for flexural and axial loading
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Antonio Tomás(UPCT); Antonio Alarcón(UPCT)"
] |
The problem of a concrete cross section under flexural and axial loading is indeterminate due to the existence of more unknowns than equations. Among the infinite solutions, it is possible to find the optimum, which is that of minimum reinforcement that satisfies certain design constraints (section ductility, minimum reinforcement area, etc.). This article proposes the automation of the optimum reinforcement calculation under any combination of flexural and axial loading. The procedure has been implemented in a program code that is attached in the Appendix. Conventional-strength or high-strength concrete may be chosen, minimum reinforcement area may be considered (it being possible to choose between the standards ACI 318 or Eurocode 2), and the neutral axis depth may be constrained in order to guarantee a certain sectional ductility. Some numerical examples are presented, drawing comparisons between the results obtained by ACI 318, EC 2 and the conventional method.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000097.xml
|
||
ART001682516
|
oai_dc
|
Modeling the compressive strength of cement mortar nano-composites
|
Modeling the compressive strength of cement mortar nano-composites
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Reza Alavi(Doust Construction Engineering Group Co); Hamed Mirzadeh(Isfahan University of Technology)"
] |
Nano-particle-reinforced cement mortars have been the basis of research in recent years and a significant growth is expected in the future. Therefore, optimization and quantification of the effect of processing parameters and mixture ingredients on the performance of cement mortars are quite important.
In this work, the effects of nano-silica, water/binder ratio, sand/binder ratio and aging (curing) time on the compressive strength of cement mortars were modeled by means of artificial neural network (ANN). The developed model can be conveniently used as a rough estimate at the stage of mix design in order to produce high quality and economical cement mortars.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000097.xml
|
||
ART001682518
|
oai_dc
|
Analysis of RC beam with unbonded or exposed tensile steel reinforcements and defective stirrup anchorages for shear strength
|
Analysis of RC beam with unbonded or exposed tensile steel reinforcements and defective stirrup anchorages for shear strength
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Xiao-Hui Wang(Shanghai Jiaotong University); Xi-La Liu(Shanghai Jiaotong University)"
] |
Although the effect of corrosion of reinforcing bar on the shear behavior of the reinforced concrete (RC) beam had been simulated by tests of the beam with unbonded, half-exposed or wholeexposed tensile steel reinforcements as well as defective stirrup anchorages, theoretical methods to accurately predict remaining capacity of this kind of RC beams, especially shear capacity, are still lacking. Considering the possible position of the critical inclined crack, the actual pattern of strains in the concrete body within the partial length and the proposed compatibility condition of deformations of the RC beam, shear strength of the RC beam with unbonded or exposed tensile steel reinforcements and/or defective stirrup anchorages is predicted. Comparison between the model’s predictions with the experimental results published in the literature shows the practicability of the proposed model. Influence of the length of unbonded or exposed tensile steel reinforcements and the percentage of stirrups lacked end anchorages on the shear strength of the RC beam is discussed. It is concluded that, the shear strength of the RC beam with unbonded or exposed tensile steel reinforcements and/or defective stirrup anchorages is greatly influenced by the length of unbonded or exposed tensile steel reinforcements and the percentage of stirrups lacked end anchorages, this influence can be adverse, insignificant or even favourable, dependent on the given parameters of the corresponding normal bonded RC beam.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000097.xml
|
||
ART001682520
|
oai_dc
|
Modeling of diffusion-reaction behavior of sulfate ion in concrete under sulfate environments
|
Modeling of diffusion-reaction behavior of sulfate ion in concrete under sulfate environments
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Xiao-Bao Zuo(Nanjing University of Science & Technology); Wei Sun(Southeast University); Hua Li(Southeast University); Yu-Kui Zhao(Nanjing University of Science & Technology)"
] |
This paper estimates theoretically the diffusion-reaction behaviour of sulfate ion in concrete caused by environmental sulfate attack. Based on Fick’s second law and chemical reaction kinetics, a nonlinear and nonsteady diffusion-reaction equation of sulfate ion in concrete, in which the variable diffusion coefficient and the chemical reactions depleting sulfate ion concentration in concrete are considered, is proposed. The finite difference method is utilized to solve the diffusion-reaction equation of sulfate ion in concrete, and then it is used to simulate the diffusion-reaction process and the concentration distribution of sulfate ion in concrete. Afterwards, the experiments for measuring the sulfate ion concentration in concrete are carried out by using EDTA method to verify the proposal model, and results show that the proposed model is basically in agreement with the experimental results. Finally, Numerical example has been completed to investigate the diffusion-reaction behavior of sulfate ion in the concrete plate specimen immersed into sulfate solution.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000097.xml
|
||
ART001682514
|
oai_dc
|
An approach of using ideal grading curve and coating paste thickness to evaluate the performances of concrete-(1) Theory and formulation
|
An approach of using ideal grading curve and coating paste thickness to evaluate the performances of concrete-(1) Theory and formulation
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"H.Y. Wang(National Kaohsiung University of Applied Sciences); C.L. Hwang(National Taiwan University of Science and Technology); S.T. Yeh(National Taiwan University of Science and Technology)"
] |
The performance of a concrete is significantly influenced by its mixture proportion and the coating thickness on aggregate surface. The concrete in this study is designed by estimating the blending ratio of aggregate using a densified mixture design algorithm (DMDA) based on an ideal grading curve and estimating the paste volume as the sum of the amount of paste needed to provide an assigned coating paste thickness. So as to obtain appropriate concrete amount, and thus can accurately estimate the property of concrete. Deduction of this mix design formula is simple and easy understanding, and meanwhile to obtain result is fast. This estimation model of mix design is expected to reward to industry and effectively upgrade concrete quality.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000097.xml
|
||
ART001682515
|
oai_dc
|
An approach of using ideal gradating curve and coating paste thickness to design concrete performance- (2) Experimental work
|
An approach of using ideal gradating curve and coating paste thickness to design concrete performance- (2) Experimental work
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"H.Y. Wang(National Kaohsiung University of Applied Sciences); C.L. Hwang(National Taiwan University of Science and Technology); S.T. Yeh(National Taiwan University of Science and Technology)"
] |
The ideal gradating curve is used in this study to estimate densified aggregate blended ratio and total surface area of aggregate, there by under assigned paste amount of concrete, and coating paste thickness can then be deduced. Four groups of concrete mixtures were prepared and the corresponding concrete properties, such as workability, compression strength, ultrasonic velocity, surface resistivity and chloride ion penetration, were measured and finally the results are interpreted in terms of “coating thickness”. The result shows as the coating thickness of the concrete is higher than critical one, the coating thickness on aggregate does affect the workability, and whatever workability is required the superplasticizer can be adjusted to achieve the demand workability. Under a fixed paste quality at the same age, coating paste thickness is inversely proportional to the concrete properties, especially as the coating thickness gets thinner.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000097.xml
|
||
ART001682513
|
oai_dc
|
Experimental and numerical investigation on in-plane behaviour of hollow concrete block masonry panels
|
Experimental and numerical investigation on in-plane behaviour of hollow concrete block masonry panels
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A. Rama Chandra Murthy(CSIR); S. Chitra Ganapathi(CSIR); Nagesh R. Iyer(CSIR); N. Lakshmanan(CSIR); N.G. Bhagavan(CSIR)"
] |
This paper presents the details of studies conducted on hollow concrete block masonry (HCBM) units and wall panels. This study includes, compressive strength of unit block, ungrouted and grouted HCB prisms, flexural strength evaluation, testing of HCBM panels with and without opening.
Non-linear finite element (FE) analysis of HCBM panels with and without opening has been carried out by simulating the actual test conditions. Constant vertical load is applied on the top of the wall panel and then lateral load is applied in incremental manner. The in-plane deformation is recorded under each incremental lateral load. Displacement ductility factors and response reduction factors have been evaluated based on experimental results. From the study, it is observed that fully grouted and partially reinforced HCBM panel without opening performed well compared to other types of wall panels in lateral load resistance and displacement ductility. In all the wall panels, shear cracks originated at loading point and moved towards the compression toe of the wall. The force reduction factor of a wall panel with opening is much less when compared with fully reinforced wall panel with no opening. The displacement values obtained by non-linear FE analysis are found to be in good agreement with the corresponding experimental values. The influence of mortar joint has been included in the stress-strain behaviour as a monolith with HCBM and not considered separately. The derived response reduction factors will be useful for the design of reinforced HCBM wall panels subjected to lateral forces generated due to earthquakes.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000097.xml
|
||
ART001711383
|
oai_dc
|
A software-assisted comparative assessment of the effect of cement type on concrete carbonation and chloride ingress
|
A software-assisted comparative assessment of the effect of cement type on concrete carbonation and chloride ingress
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S. Demis(AEIPLOUS Institute for Innovation & Sustainable Development); V.G. Papadakis(University of Western Greece)"
] |
Utilization of supplementary cementing materials (SCM) by the cement industry, as a highly promising solution of sustainable cement development aiming to reduce carbon dioxide emissions, necessitates a more thorough evaluation of these types of materials on concrete durability. In this study a comparative assessment of the effect of SCM on concrete durability, of every cement type as defined in the European Standard EN 197-1 is taking place, using a software tool, based on proven predictive models (according to performance-related methods for assessing durability) developed and wide-validated for the estimation of concrete service life when designing for durability under harsh environments. The effect of Type II additives (fly ash, silica fume) on CEM I type of cement, as well as the effect of every Portland-composite type of cement (and others) are evaluated in terms of their performance in carbonation and chloride exposure, for a service life of 50 years. The main aim is to portray a unified and comprehensive evaluation of the efficiency of SCM in order to create the basis for future consideration of more types of cement to enter the production line in industry.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001711374
|
oai_dc
|
Software for adaptable eccentric analysis of confined concrete circular columns
|
Software for adaptable eccentric analysis of confined concrete circular columns
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Hayder A. Rasheed(Kansas State University); Ahmed M. Abd El-Fattah(King Fahd University of Petroleum and Minerals); Asad Esmaeily(Kansas State University); John P. Jones(Bridge Design Office); Kenneth F. Hurst(Bridge Design Office)"
] |
This paper describes the varying material model, the analysis method and the software development for reinforced concrete circular columns confined by spiral or hoop transverse steel reinforcement and subjected to eccentric loading. The widely used Mander model of concentric loading is adapted here to eccentric loading by developing an auto-adjustable stress-strain curve based on the eccentricity of the axial load or the size of the compression zone to generate more accurate interaction diagrams. The prediction of the ultimate unconfined capacity is straight forward. On the other hand, the prediction of the actual ultimate capacity of confined concrete columns requires specialized nonlinear analysis. This nonlinear procedure is programmed using C-Sharp to build efficient software that can be used for design, analysis, extreme event evaluation and forensic engineering. The software is equipped with an elegant graphics interface that assimilates input data, detail drawings, capacity diagrams and demand point mapping in a single sheet. Options for preliminary design, section and reinforcement selection are seamlessly integrated as well. Improvements to KDOT Bridge Design Manual using this software with reference to AASHTO LRFD are made.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001711384
|
oai_dc
|
Quality assessment of high performance concrete using digitized image elements
|
Quality assessment of high performance concrete using digitized image elements
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Sheng-Szu Peng(Minghsin University of Science and Technology); Her-Yung Wang(National Kaohsiung University of Applied Sciences); Yu-Te Chou(National Kaohsiung University of Applied Sciences); Edward H. Wang(Minghsin University of Science and Technology)"
] |
The quality of high performance concrete largely depends on water cement ratio, porosity,material composition and mix methods. The uniformity of color, texture and compressive strengths are quality indicators commonly used to assess the overall characteristics of concrete mixes. The homogeneity and share of coarse aggregates play a key role in concrete quality and must be analyzed in a microscopic point of view. This research studies the quality of high performance concrete by taking drilled cores in both horizontal and vertical directions from a 1.0 m3 specimen. The coarse aggregate, expressed in digitized 100×116 dpi resolution images are processed based on brightness in colors through commercial software converted into text files. With the image converting to text format, the share of coarse aggregate is quantified leading to a satisfactory assessment of homogeneity – a quality index of high performance concrete. The compressive strengths of concrete and the shares of coarse aggregate of the samples are also compared in this research study to illustrate its correlation in concrete quality. It is concluded that a higher homogeneity of aggregate exists in the vertical plane than that of the horizontal planes of the high performance concrete. In addition, the concrete specimen showing denser particle packing has relatively higher compressive strengths. The research methodology provides an easy-to-use, direct measurement of high performance concrete when conducting quality assessment in the construction site.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001711376
|
oai_dc
|
Permeability and abrasion resistance of concretes containing high volume fine fly ash and palm oil fuel ash
|
Permeability and abrasion resistance of concretes containing high volume fine fly ash and palm oil fuel ash
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S. Homwuttiwong(Mahasarakham University); C. Jaturapitakkul(King Mongkut’s University of Technology Thonburi (KMUTT)); P. Chindaprasirt(Khon Kaen University)"
] |
In this paper, compressive strength, water permeability and abrasion resistance of concretes containing high volume fine fly ash (FFA) and fine ground palm oil fuel ash (GPA) were studied. Portland cement type I was replaced with FFA and GPA at dosages up to 70% by weight of binder. Ground river sand (GRS) was also used to replace Portland cement in order to indicate the level of filler effect. Results indicated that FFA was slightly more reactive than GPA. The replacement of 40-70% of FFA produced concretes with compressive strength, permeability and abrasion resistance comparable to those of normal concretes. The incorporation of GPA slightly reduced the performances of concretes as compared to those of FFA concretes. The reduction of Portland cement was partly compensated by the increase in pozzolanic activity of the fine fly ash and palm oil fuel ash and thus enabled the large replacement levels.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001711385
|
oai_dc
|
Modeling of nonlinear response of R/C shear deficient t-beam subjected to cyclic loading
|
Modeling of nonlinear response of R/C shear deficient t-beam subjected to cyclic loading
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"R.A. Hawileh(American University of Sharjah); M.H. Tanarslan(Dokuz Eylul University); J. A. Abdalla(American University of Sharjah)"
] |
This paper presents a finite element (FE) model for predicting the nonlinear response and behavior of a reinforced concrete T-beam deficient in shear under cyclic loading. Cracking loads, failure loads, response hysteresis envelopes and crack patterns were used as bench mark for comparison between experimental and FE results. A parametric study was carried out to predict the optimum combination of the open and close crack shear transfer coefficients (βt and βc) of the constitutive material model for concrete. It is concluded that when both shear transfer coefficients are equal to 0.2 the FE results gave the best correlation with the experimental results. The results were also verified on a rectangular shear deficient beam (R-beam) tested under cyclic loading and it is concluded that the variation of section geometry has no effect on the optimum choice of the values of shear transfer coefficients of 0.2. In addition, a parametric study based on the variation of concrete compressive strength, was carried out on the T-beam and it is observed that the variation of concrete compressive strength has little effect on the deflection. Further conclusions and observations were also drawn.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001711377
|
oai_dc
|
Investigation of the shear behaviour of multi-story reinforced concrete walls with eccentric openings
|
Investigation of the shear behaviour of multi-story reinforced concrete walls with eccentric openings
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Rafik Taleb(Saad Dahleb Blida University); Hakim Bechtoula(Rue Kaddour RAHIM); Masanubo Sakashita(Kyoto University); Noureddine Bourahla(Saad Dahleb Blida University); Susumu Kono(Kyoto University)"
] |
Four Reinforced Concrete (RC) single span structural walls having various opening sizes and locations were constructed and tested under lateral reversed cyclic loading at the structural laboratory of Kyoto University. These specimens were scaled to 40% and represented the lower three stories of a sixstoried RC building. The main purposes of the experimental tests were to evaluate the shear behavior and to identify the influence of opening ratios on the cracks distribution and shear strength of RC structural walls. The shear strength of the specimens was estimated by combining the shear strength of structural wall without openings and the reduction factor that takes into account the openings. Experimental and analytical results showed that the shear strength was different depending on the loading direction due to opening locations. A two-dimensional finite element analysis was carried out to simulate the performance of the tested specimens. The constructed finite elements model simulated the lateral load-drift angle relations quite well.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001711382
|
oai_dc
|
Using generalized regression neural network (GRNN) for mechanical strength prediction of lightweight mortar
|
Using generalized regression neural network (GRNN) for mechanical strength prediction of lightweight mortar
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"S.V. Razavi(Jundi-Shapur University of Technology); M.Z. Jumaat(University Malaya(UM)); E.S. Ahmed H(Universiti Kebangsaan Malaysia(UKM)); Mohammadi, P.(Islamic Azad University)"
] |
In this paper, the mechanical strength of different lightweight mortars made with 0, 5, 10, 15,20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 and 100 percentage of scoria instead of sand and 0.55 water-cement ratio and 350 kg/m3 cement content is investigated. The experimental result showed 7.9%, 16.7% and 49% decrease in compressive strength, tensile strength and mortar density, respectively, by using 100% scoria instead of sand in the mortar. The normalized compressive and tensile strength data are applied for artificial neural network (ANN) generation using generalized regression neural network (GRNN). Totally, 90 experimental data were selected randomly and applied to find the best network with minimum mean square error (MSE) and maximum correlation of determination. The created GRNN with 2 input layers, 2 output layers and a network spread of 0.1 had minimum MSE close to 0 and maximum correlation of determination close to 1.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001719189
|
oai_dc
|
Plastic hinge length of circular reinforced concrete columns
|
Plastic hinge length of circular reinforced concrete columns
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Yu-Chen Ou(National Taiwan University of Science and Technology); Raditya Andy Kurniawan(National Taiwan University of Science and Technology); Dimas Pramudya Kurniawan(National Taiwan University of Science and Technology); Nguyen Dang Nguyen(National Taiwan University of Science and Technology)"
] |
This paper presents a parametric study of the plastic hinge length of circular reinforced concrete columns using a three-dimensional finite element analysis method, and using the Taguchi robust design method to reduce computational cost. Parameters examined include the longitudinal reinforcing ratio, the shear span-to-depth ratio, the axial force ratio and the concrete compressive strength. The study considers longitudinal reinforcement with yield strengths of 414 MPa and 685 MPa, and proposes simplified formulas for the plastic hinge length of circular reinforced concrete columns, showing that increases in plastic hinge length correlate to increases in the axial load, longitudinal reinforcing and shear span-todepth ratios. As concrete strength increases, the plastic hinge length decreases for the 414 MPa case but increases for the 685 MPa case.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001719187
|
oai_dc
|
An investigation on the mortars containing blended cement subjected to elevated temperatures using Artificial Neural Network (ANN) models
|
An investigation on the mortars containing blended cement subjected to elevated temperatures using Artificial Neural Network (ANN) models
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"A.A. Ramezanianpour(Amirkabir University of Technology); M.E. Kamel(University of Tehran); E. Ghiasvand(Amirkabir University of Technology); H. Shokrani(Amirkabir University of Technology); N. Bakhshi(Amirkabir University of Technology); A. Kazemian(Amirkabir University of Technology)"
] |
This paper presents the results of an investigation on the compressive strength and weight loss of mortars containing three types of fillers as cement replacements; Limestone Filler (LF), Silica Fume (SF) and Trass (TR), subjected to elevated temperatures including 400oC, 600oC, 800oC and 1000oC. Results indicate that addition of TR to blended cements, compared to SF addition, leads to higher compressive strength and lower weight loss at elevated temperatures. In order to model the influence of the different parameters on the compressive strength and the weight loss of specimens, artificial neural networks (ANNs) were adopted. Different diagrams were plotted based on the predictions of the most accurate networks to study the effects of temperature, different fillers and cement content on the target properties. In addition to the impressive RMSE and R2 values of the best networks, the data used as the input for the prediction plots were chosen within the range of the data introduced to the networks in the training phase.
Therefore, the prediction plots could be considered reliable to perform the parametric study.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001719183
|
oai_dc
|
Concrete mix design for service life of RC structures exposed to chloride attack
|
Concrete mix design for service life of RC structures exposed to chloride attack
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"권성준(한남대학교); 김상철(Hanseo University)"
] |
The purpose of this research is to propose a design technique of concrete mix proportions satisfying service life through genetic algorithm (GA) and neural network (NN). For this, thirty mix proportions and the related diffusion coefficients in high performance concrete are analyzed and fitness function for diffusion coefficient is obtained considering mix components like w/b (water to binder ratio), cement content, mineral admixture (slag, flay ash and silica fume) content, sand and coarse aggregate content. Through averaging the results of 10 times GA simulations, relative errors to the previous data decrease lower than 5.0% and the simulated mix proportions are verified with the experimental results. Assuming the durability design parameters, intended diffusion coefficient for intended service life is derived and mix proportions satisfying the service life are obtained. Among the mix proportions, the most optimized case which satisfies required concrete strength and the lowest cost is selected through GA algorithm. The proposed technique would be improved with the enhancement of comprehensive data set including wider the range of diffusion coefficients.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001719185
|
oai_dc
|
Application of Fuller’s ideal curve and error function to making high performance concrete using rice husk ash
|
Application of Fuller’s ideal curve and error function to making high performance concrete using rice husk ash
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Chao-Lung Hwang(National Taiwan University of Science and Technology); Le Anh-Tuan Bui(National Taiwan University of Science and Technology); Chun-Tsun Chen(National Taiwan University of Science and Technology)"
] |
This paper focuses on the application of Fuller’s ideal gradation curve to theoretically design blended ratio of all solid materials of high performance concrete (HPC), with the aid of error function, and then to study the effect of rice husk ash (RHA) on the performance of HPC. The residual RHA, generated when burning rice husk pellets at temperatures varying from 600 to 800oC, was collected at steam boilers in Vietnam. The properties of fresh and hardened concrete are reviewed. It is possible to obtain the RHA concrete with comparable or better properties than those of the specimen without RHA with lower cement consumption. High flowing concrete designed by the proposed method was obtained without bleeding or segregation. The application of the proposed method for HPC can save over 50% of the consumption of cement and limit the use of water. Its strength efficiency of cement in HPC is 1.4-1.9 times higher than that of the traditional method. Local standards of durability were satisfied at the age of 91 days both by concrete resistivity and ultrasonic pulse velocity.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001719184
|
oai_dc
|
Investigation into the behaviour of deep beam with web openings by finite element
|
Investigation into the behaviour of deep beam with web openings by finite element
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Jeung-Hwan Doh(Griffith University Gold Coast Campus); Tae-Min Yoo(Griffith University Gold Coast Campus); Dane Miller(Griffith University Gold Coast Campus); Hong Guan(Griffith University Gold Coast Campus); Sam Fragomeni(Victoria University)"
] |
Currently, the design of reinforced concrete deep beams with web openings is carried out using empirical or semi-empirical methods and hence their scope of application is limited. In particular, high strength concrete deep beams with various web opening configurations have been given little treatment. In view of this, a nonlinear layered finite element method (LFEM) for cracking and failure analysis of reinforced concrete structures is used to conduct a parametric study to investigate reinforced concrete deep beams various web opening behaviours. This paper initially presents comparisons of LFEM output with published test results to numerical techniques. The paper then focuses on a parametric study on the shear strengths of deep beams with varying web opening configurations such as opening sizes and locations. The results confirm that the current design methods are inadequate in predicting the maximum shear strength when web openings are present. A series of parametric study offers insight into the maximum shear strength of the deep beams being critically influenced by the size and location of web openings.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001719182
|
oai_dc
|
Numerical crack modelling of tied concrete columns under compression
|
Numerical crack modelling of tied concrete columns under compression
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"C. Bosco(Politecnico di Torino); S. Invernizzi(Politecnico di Torino)"
] |
In the present paper the problem of monotonically compressed concrete columns is studied numerically, accounting for transverse steel reinforcement and concrete cracking. The positive confinement effect of the ties on the core concrete is modeled explicitly and studied in the case of distributed or concentrated vertical load. The main aim is to investigate the influence of transverse reinforcement steel characteristics on the column load carrying capacity and ductility, in order to provide an evaluation about some standards requirements about the class and ductility of steel to be used for ties. The obtained results show that the influence of transverse reinforcement steel class of ductility is negligible both on the column load carrying capacity and on its ductility. Also the dissipated energy is basically unchanged. In view of these evidences, some standards requirements about the steel class of ductility to be used for ties appear to be rather questionable.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001719181
|
oai_dc
|
Predicting concrete properties using neural networks (NN) with principal component analysis (PCA) technique
|
Predicting concrete properties using neural networks (NN) with principal component analysis (PCA) technique
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"B. Boukhatem(University of Blida); A.T. Hamou(University of Sherbrooke); Dj. Ziou(University of Sherbrooke); M. Ghrici(University of Chlef); S. Kenai(University of Blida)"
] |
This paper discusses the combined application of two different techniques, Neural Networks (NN) and Principal Component Analysis (PCA), for improved prediction of concrete properties. The combination of these approaches allowed the development of six neural networks models for predicting slump and compressive strength of concrete with mineral additives such as blast furnace slag, fly ash and silica fume. The Back-Propagation Multi-Layer Perceptron (BPMLP) with Bayesian regularization was used in all these models. They are produced to implement the complex nonlinear relationship between the inputs and the output of the network. They are also established through the incorporation of a huge experimental database on concrete organized in the form Mix-Property. Thus, the data comprising the concrete mixtures are much correlated to each others. The PCA is proposed for the compression and the elimination of the correlation between these data. After applying the PCA, the uncorrelated data were used to train the six models. The predictive results of these models were compared with the actual experimental trials. The results showed that the elimination of the correlation between the input parameters using PCA improved the predictive generalisation performance models with smaller architectures and dimensionality reduction. This study showed also that using the developed models for numerical investigations on the parameters affecting the properties of concrete is promising.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001719171
|
oai_dc
|
Determination of plastic hinge properties for static nonlinear analysis of FRP-strengthened circular columns in bridges
|
Determination of plastic hinge properties for static nonlinear analysis of FRP-strengthened circular columns in bridges
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Gholamreza Ghodrati Amiri(Iran University of Science & Technology); Azadeh Jaberi Jahromi(Iran University of Science & Technology); Benyamin Mohebi(Imam Khomeini International University)"
] |
In the recent years, rehabilitation of structures, strengthening and increasing the ductility of them under seismic loads have become so vital that many studies has been carried out on the retrofit of steel and concrete members so far. Bridge piers are very important members concerning rehabilitation, in which the plastic hinging zone is very vulnerable. Pier is usually confined by special stirrups predicted in the design procedure; moreover, fiber-reinforced polymers (FRP) jackets are used after construction to confine the pier. FRP wrapping of the piers is one of the most effective ways of increasing moment and ductility capacity of them, which has a growing application due to its relative advantages. In many earthquake-resistant bridges, reinforced concrete columns have a major defect which could be retrofitted in different ways like using FRP. After rehabilitation, it is important to check the strengthening adequacy by dynamic nonlinear analysis and precise modeling of material properties. If the plastic hinge properties are simplified for the strengthened members, as the simplified properties which FEMA 356 proposes for nonstrengthened members, static nonlinear analysis could be performed more easily. Current paper involves this matter and it is intended to determine the plastic hinge properties for static nonlinear analysis of the FRP-strengthened circular columns.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001719173
|
oai_dc
|
Regression-based algorithms for exploring the relationships in a cement raw material quarry
|
Regression-based algorithms for exploring the relationships in a cement raw material quarry
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Bulent Tutmez(Inonu University); Ahmet Dag(Cukurova University)"
] |
Using appropriate raw materials for cement is crucial for providing the required products. Monitoring relationships and analyzing distributions in a cement material quarry are important stages in the process. CaO, one of the substantial chemical components, is included in some raw materials such as limestone and marl; furthermore, appraising spatial assessment of this chemical component is also very critical. In this study, spatial evaluation and monitoring of CaO concentrations in a cement site are considered. For this purpose, two effective regression-based models were applied to a cement quarry located in Turkey. For the assessment, some spatial models were developed and performance comparisons were carried out. The results show that the regression-based spatial modelling is an efficient methodology and it can be employed to evaluate spatially varying relationships in a cement quarry.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001719179
|
oai_dc
|
Modeling of chloride diffusion in a hydrating concrete incorporating silica fume
|
Modeling of chloride diffusion in a hydrating concrete incorporating silica fume
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"왕소용(강원대학교); 박기봉(강원대학교); 이한승(한양대학교)"
] |
Silica fume has long been used as a mineral admixture to improve the durability and produce high strength and high performance concrete. And in marine and coastal environments, penetration of chloride ions is one of the main mechanisms causing concrete reinforcement corrosion. In this paper, we proposed a numerical procedure to predict the chloride diffusion in a hydrating silica fume blended concrete. This numerical procedure includes two parts: a hydration model and a chloride diffusion model. The hydration model starts with mix proportions of silica fume blended concrete and considers Portland cement hydration and silica fume reaction respectively. By using the hydration model, the evolution of properties of silica fume blended concrete is predicted as a function of curing age and these properties are adopted as input parameters for the chloride penetration model. Furthermore, based on the modeling of physicochemical processes of diffusion of chloride ion into concrete, the chloride distribution in silica fume blended concrete is evaluated. The prediction results agree well with experiment results of chloride ion concentrations in the hydrating concrete incorporating silica fume.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001719177
|
oai_dc
|
Nonlinear modeling of flat-plate structures using grid beam elements
|
Nonlinear modeling of flat-plate structures using grid beam elements
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ying Tian(University of Nevada Las Vegas); Jianwei Chen(Hebei United University); Aly Said(University of Nevada Las Vegas); Jian Zhao(University of Wisconsin)"
] |
This paper presents a simplified grid beam model for simulating the nonlinear response of reinforced concrete flat-plate structures. The beam elements are defined with nonlinear behavior for bending moment and torsion. The flexural stiffness and torsional strength of the beam elements are defined based on experimental data to implicitly account for slab two-way bending effects. A failure criterion that considers the interaction between the punching strength and slab flexural behavior is incorporated in the model. The effects of bond-slip of slab reinforcement on connection stiffness are examined. The proposed grid beam model is validated by simulating large-scale tests of slab-column connections subjected to concentric gravity loading and unbalanced moment. This study also determines the critical parameters for a hysteretic model used to simulate flat-plates subjected to cyclic lateral loading.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001719178
|
oai_dc
|
Reliability of column capacity design in shear
|
Reliability of column capacity design in shear
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"George C. Thomos(National Technical University of Athens); Constantin G. Trezos(National Technical University of Athens)"
] |
The capacity design of shear forces is one of the special demands of EC8 by which the ductile behavior of structures is implemented. The aim of capacity design is the formation of plastic hinges without shear failure of the elements. This is achieved by deriving the design shear forces from equilibrium conditions, assuming that plastic hinges, with their possible over-strengths, have been formed in the adjacent joints of the elements. In this equilibrium situation, the parameters (dimensions, material properties, axial forces etc) are random variables. Therefore, the capacity design of shear forces is associated with a probability of non-compliance (probability of failure). In the present study the probability of non-compliance of the shear capacity design in columns is calculated by assuming the basic variables as random variables. Parameters affecting this probability are examined and a modification of the capacity design is proposed, in order to achieve uniformity of the safety level.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001719180
|
oai_dc
|
Nonlinear analysis of service stresses in reinforced concrete sections-closed form solutions
|
Nonlinear analysis of service stresses in reinforced concrete sections-closed form solutions
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Helena F.M. Barros(INESC Coimbra); Rogério A.F. Martins(Lusíada University)"
] |
This paper presents an algorithm for the evaluation of stresses in reinforced concrete sections under service loads. The algorithm is applicable to any section defined by polygonal contours and is based on an analytical integration of the stresses. The nonlinear behaviour of concrete is represented by the parabola-rectangle law used in the Eurocode-2 for the ultimate concrete design. An integrated definition of the strains in concrete and steel is possible by the use of Heaviside functions, similarly to what is done for ultimate section design in Barros et al. (2004). Other constitutive equations for the definition of the stresses in the concrete or steel can be easily incorporated into the code. The examples presented consist in the evaluation of resulting axial load and bending moment in an irregular section and in a section in L shape. The results, for service stresses, can also be plotted in terms of design abacus; a rectangular doubly reinforced section is presented as example.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001719176
|
oai_dc
|
Towards a model of dry shear keyed joints: modelling of panel tests
|
Towards a model of dry shear keyed joints: modelling of panel tests
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"J. Turmo(Universitat Politècnica de Catalunya); G. Ramos(Universitat Politècnica de Catalunya); A.C. Aparicio(Universitat Politècnica de Catalunya)"
] |
This paper presents a study on the behaviour of the joints of segmental concrete bridges with external prestressing, focusing on the structural response of dry non-epoxied joints with shear keys. A Finite Element joint model to study such structures is validated modelling eight concrete panel tests. The most important feature of this model is that it has been validated with experimental tests on concrete panels which were specifically designed to fail in shear. Interface elements are used to reproduce the non linear behaviour of the joint and parameters deduced from the tests are used to define the constitutive law of these elements. This joint model is of great importance because it will permit the development of a structural model that faithfully reproduces the behaviour of these structures under combined flexure and shear and the study of its global behaviour after the opening of the joints. Interesting conclusions about the behaviour of the dry joints, about the contribution of the different mechanisms transferring shear (friction and cohesion) and about the shear stress distribution in the joint have been reached.
|
토목공학
| null |
kci_detailed_000097.xml
|
|||
ART001661400
|
oai_dc
|
Prediction of elastic modulus of steel-fiber reinforced concrete (SFRC) using fuzzy logic
|
Prediction of elastic modulus of steel-fiber reinforced concrete (SFRC) using fuzzy logic
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Mustafa Gençoglu(Istanbul Technical University); Fuat Demir(Süleyman Demirel University); Kadir Güler(Istanbul Technical University); Tayfun Uygunoglu(Afyon Kocatepe University)"
] |
In this study, the modulus of elasticity of low, normal and high strength steel fiber reinforced concrete has been predicted by developing a fuzzy logic model. The fuzzy models were formed as simple rules using only linguistic variables. A fuzzy logic algorithm was devised for estimating the elastic modulus of SFRC from compressive strength. Fibers used in all of the mixes were made of steel, and they were in different volume fractions and aspect ratios. Fiber volume fractions of the concrete mixtures have changed between 0.25%-6%. The results of the proposed approach in this study were compared with the results of equations in standards and codes for elastic modulus of SFRC. Error estimation was also carried out for each approach. In the study, the lowest error deviation was obtained in proposed fuzzy logic approach. The fuzzy logic approach was rather useful to quickly and easily predict the elastic modulus of SFRC.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000098.xml
|
||
ART001661397
|
oai_dc
|
Viscoelastic behaviour of non-homogeneous variable-section beams with post-poned restraints
|
Viscoelastic behaviour of non-homogeneous variable-section beams with post-poned restraints
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Alessandra Fiore(Politecnico di Bari); Pietro Monaco(Politecnico di Bari); Domenico Raffaele(Politecnico di Bari)"
] |
The aim of this paper is to develop a procedure able to calculate the long-term stress and strain patterns in modern prestressed composite structures which are largely influenced by creep and shrinkage and whose final static configuration is the result of many phases of loading and restraints conditions. The introduction of equivalent moduli, depending on the viscous and elastic features of materials, can guarantee a significant simplification of the problem presented above. The proposed calculation model has been used to design the “Quattroquercie Viaduct” located on the highway “A3”Salerno-Reggio Calabria, Italy.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000098.xml
|
||
ART001661399
|
oai_dc
|
Automatic categorization of chloride migration into concrete modified with CFBC ash
|
Automatic categorization of chloride migration into concrete modified with CFBC ash
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Maria Marks(Institute of Fundamental Technological Research); Daria Józwiak-Niedzwiedzka(Institute of Fundamental Technological Research); Micha A. Glinicki(Institute of Fundamental Technological Research)"
] |
The objective of this investigation was to develop rules for automatic categorization of concrete quality using selected artificial intelligence methods based on machine learning. The range of tested materials included concrete containing a new waste material - solid residue from coal combustion in fluidized bed boilers (CFBC fly ash) used as additive. The rapid chloride permeability test - Nordtest Method BUILD 492 method was used for determining chloride ions penetration in concrete. Performed experimental tests on obtained chloride migration provided data for learning and testing of rules discovered by machine learning techniques. It has been found that machine learning is a tool which can be applied to determine concrete durability. The rules generated by computer programs AQ21 and WEKA using J48 algorithm provided means for adequate categorization of plain concrete and concrete modified with CFBC fly ash as materials of good and acceptable resistance to chloride penetration.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000098.xml
|
||
ART001661393
|
oai_dc
|
Optimum design of reinforced concrete columns subjected to uniaxial flexural compression
|
Optimum design of reinforced concrete columns subjected to uniaxial flexural compression
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"R. Bordignon(University of Passo Fundo); M. Kripka(University of Passo Fundo)"
] |
The search for a design that meets both performance and safety, with minimal cost and lesser environmental impact was always the goal of structural engineers. In general, the design of conventional reinforced concrete structures is an iterative process based on rules of thumb established from the personal experience and intuition of the designer. However, such procedure makes the design process exhaustive and only occasionally leads to the best solution. In such context, this work presents the development and implementation of a mathematical formulation for obtaining optimal sections of reinforced concrete columns subjected to uniaxial flexural compression, based on the verification of strength proposed by the Brazilian standard NBR 6118 (ABNT 2007). To minimize the cost of the reinforced concrete columns, the Simulated Annealing optimization method was used, in which the amount and diameters of the reinforcement bars and the dimensions of the columns cross sections were considered as discrete variables. The results obtained were compared to those obtained from the conventional design procedure and other optimization methods, in an attempt to verify the influence of resistance class, variations in the magnitudes of bending moment and axial force, and material costs on the optimal design of reinforced concrete columns subjected to uniaxial flexural compression.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000098.xml
|
||
ART001661395
|
oai_dc
|
Compressive behavior of reinforced concrete columns confined by multi-spiral hoops
|
Compressive behavior of reinforced concrete columns confined by multi-spiral hoops
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Y. Chen(Southeast University); S. Yin(Ruentex Group); J. Feng(Southeast University); 윤현도(충남대학교)"
] |
Numerical studies are performed to predict the stress-strain behavior of rectangular RC columns confined by multi-spiral hoops under axial and eccentric compressions. Using the commercial finite element package ABAQUS, the Drucker-Prager criterion and the yield surface are adopted for damaged plasticity concrete. The proposed finite element models are compared with the published experimental data. Parametric studies on concrete grades, confinement arrangement, diameter and spacing of hoops and eccentricity of load are followed. Numerical results have shown good agreements with experimental values, and indicated a proper constitutive law and model for concrete. Cross-sectional areas and spacing of the hoops have significant effect on the bearing capacity. It can be concluded that rectangular RC columns confined by multi-spiral hoops show better performance than the conventional ones.
|
토목공학
| null |
http://dx.doi.org/
|
kci_detailed_000098.xml
|
||
ART001544639
|
oai_dc
|
Mesoscale simulation of chloride diffusion in concrete considering the binding capacity and concentration dependence
|
Mesoscale simulation of chloride diffusion in concrete considering the binding capacity and concentration dependence
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Licheng Wang(Dalian University of Technology); Tamon Ueda(Hokkaido University)"
] |
In the present paper, a numerical simulation method based on mesoscopic composite structure of concrete, the truss network model, is developed to evaluate the diffusivity of concrete in order to account for the microstructure of concrete, the binding effect of chloride ions and the chloride concentration dependence. In the model, concrete is described as a three-phase composite, consisting of mortar, coarse aggregates and the interfacial transition zones (ITZs) between them. The advantage of the current model is that it can easily represent the movement of mass (e.g. water or chloride ions) through ITZs or the potential cracks within concrete. An analytical method to estimate the chloride diffusivity of mortar and ITZ, which are both treated as homogenious materials in the model, is introduced in terms of water-tocement ratio (w/c) and sand volume fraction. Using the newly developed approaches, the effect of cracking of concrete on chloride diffusion is reflected by means of the similar process as that in the test. The results of calculation give close match with experimental observations. Furthermore, with consideration of the binding capacity of chloride ions to cement paste and the concentration dependence for diffusivity, the onedimensional nonlinear diffusion equation is established, as well as its finite difference form in terms of the truss network model. A series of numerical analysises performed on the model find that the chloride diffusion is substantially influenced by the binding capacity and concentration dependence, which is same as that revealed in some experimental investigations. This indicates the necessity to take into account the binding capacity and chloride concentration dependence in the durability analysis and service life prediction of concrete structures.
|
토목공학
| null |
kci_detailed_000098.xml
|
|||
ART001544641
|
oai_dc
|
Theoretical prediction on thickness distribution of cement paste among neighboring aggregates in concrete
|
Theoretical prediction on thickness distribution of cement paste among neighboring aggregates in concrete
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Huisu Chen(Southeast University); Lambertus Johannes Sluys(Delft University of Technology); Piet Stroeven(Delft University of Technology); Wei Sun(Southeast University)"
] |
By virtue of chord-length density function from the field of statistical physics, this paper introduced a quantitative approach to estimate the distribution of cement paste thickness between aggregates in concrete. Dynamics mixing method based on molecular dynamics was employed to generate one model structure, then image analysis algorithm was used to obtain the distribution of thickness of cement paste in model structure for the purpose of verification. By comparison of probability density curves and cumulative probability curves of the cement paste thickness among neighboring aggregates, it is found that the theoretical results are consistent with the simulation. Furthermore, for the model mortar and concrete mixtures with practical volume fraction of Fuller-type aggregate, this analytical formula was employed to predict the influence of aggregate volume fraction and aggregate fineness. And evolution of its mean values were also investigated with the variation of volume fraction of aggregate as well as the fineness of aggregates in model mortars and concretes.
|
토목공학
| null |
kci_detailed_000098.xml
|
|||
ART001544644
|
oai_dc
|
Maximum concrete stress developed in unconfined flexural RC members
|
Maximum concrete stress developed in unconfined flexural RC members
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"J.C.M. Ho(The University of Hong Kong); H.J. Pam(The University of Hong Kong); J. Peng(The University of Hong Kong); Y.L. Wong(The Hong Kong Polytechnic University)"
] |
In flexural strength design of unconfined reinforced concrete (RC) members, the concrete compressive stress-strain curve is scaled down from the uni-axial stress-strain curve such that the maximum concrete stress adopted in design is less than the uni-axial strength to account for the strain gradient effect. It has been found that the use of this smaller maximum concrete stress will underestimate the flexural strength of unconfined RC members although the safety factors for materials are taken as unity. Herein, in order to investigate the effect of strain gradient on the maximum concrete stress that can be developed in unconfined flexural RC members, several pairs of plain concrete (PC) and RC inverted T-shaped specimens were fabricated and tested under concentric and eccentric loads. From the test results, the maximum concrete stress developed in the eccentric specimens under strain gradient is determined by the modified concrete stress-strain curve obtained from the counterpart concentric specimens based on axial load and moment equilibriums. Based on that, a pair of equivalent rectangular concrete stress block parameters for the purpose of flexural strength design of unconfined RC members is determined.
|
토목공학
| null |
kci_detailed_000098.xml
|
|||
ART001544645
|
oai_dc
|
Variables affecting strain sensing function in cementitious composites with carbon fibers
|
Variables affecting strain sensing function in cementitious composites with carbon fibers
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"F.J. Baeza(Universidad de Alicante); E. Zornoza(Universidad de Alicante); L.G. Andión(Universidad de Alicante); S. Ivorra(Universidad de Alicante); P. Garcés(Universidad de Alicante)"
] |
In this work, cement paste samples with 1% (by cement mass) of a conductive carbon fiber admixture have been studied under uniaxial compression. Three different arrangements were used to measure the resistivity of the samples. According to the results obtained, the resistance should be measured using the four wire method in order to obtain good sensitivity and repeatability. The effect of the load value and the load rate on the fractional change of the volume resistivity has been determined. It has been observed that the gage factor (fractional change in resistance respect to strain) increases when the maximum load is increased, and the loading rate does not affect significantly this parameter. The effect of the sample ambient humidity on the material piezoresistivity has also been studied, showing that the response of the composite is highly affected by this parameter.
|
토목공학
| null |
kci_detailed_000098.xml
|
|||
ART001544642
|
oai_dc
|
Enhanced mass balance Tafel slope model for computer based FEM computation of corrosion rate of steel reinforced concrete coupled with CO_2 transport
|
Enhanced mass balance Tafel slope model for computer based FEM computation of corrosion rate of steel reinforced concrete coupled with CO_2 transport
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Raja Rizwan Hussain(King Saud University Riyadh)"
] |
This research paper aims at computer based modeling of carbonation induced corrosion under extreme conditions and its experimental verification by incorporating enhanced electrochemical and mass balance equations based on thermo-hygro physics with strong coupling of mass transport and equilibrium in micro-pore structure of carbonated concrete for which the previous research data is limited. In this paper the carbonation induced electrochemical corrosion model is developed and coupled with carbon dioxide transport computational model by the use of a concrete durability computer based model DuCOM developed by our research group at concrete laboratory in the University of Tokyo and its reliability is checked in the light of experiment results of carbonation induced corrosion mass loss obtained in this research. The comparison of model analysis and experiment results shows a fair agreement. The carbonation induced corrosion model computation reasonably predicts the quantitative behavior of corrosion rate for normal air dry relative humidity conditions. The computational model developed also shows fair qualitative corrosion rate simulation and analysis for various pH levels and coupled environmental actions of chloride and carbonation. Detailed verification of the model for the quantitative carbonation induced corrosion rate computation under varying relative conditions, different pH levels and combined effects of carbonation and chloride attack remain as scope for future research.
|
토목공학
| null |
kci_detailed_000098.xml
|
|||
ART001544643
|
oai_dc
|
Modeling of nonlinear cyclic response of shear-deficient RC T-beams strengthened with side bonded CFRP fabric strips
|
Modeling of nonlinear cyclic response of shear-deficient RC T-beams strengthened with side bonded CFRP fabric strips
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Rami A. Hawileh(American University of Sharjah); Jamal A. Abdalla(American University of Sharjah); Murat H. Tanarslan(Dokuz Eylul University); Mohannad Z. Naser(American University of Sharjah)"
] |
The use of Carbon Fiber Reinforced Polymers (CFRP) to strengthen reinforced concrete beams under bending and shear has gained rapid growth in recent years. The performance of shear strengthened beams with externally bonded CFRP laminate or fabric strips is raising many concerns when the beam is loaded under cyclic loading. Such concerns warrant experimental, analytical and numerical investigation of such beams under cyclic loading. To date, limited investigations have been carried out to address this concern. This paper presents a numerical investigation by developing a nonlinear finite element (FE) model to study the response of a cantilever reinforced concrete T-beam strengthened in shear with side bonded CFRP fabric strips and subjected to cyclic loading. A detailed 3D nonlinear finite element model that takes into account the orthotropic nature of the polymer’s fibers is developed. In order to simulate the bond between the CFRP sheets and concrete, a layer having the material properties of the adhesive epoxy resin is introduced in the model as an interface between the CFRP sheets and concrete surface. Appropriate numerical modeling strategies were used and the response envelope and the loaddisplacement hysteresis loops of the FE model were compared with the experimental response at all stages of the cyclic loading. It is observed that the responses of the FE beam model are in good agreement with those of the experimental test. A parametric study was conducted using the validated FE model to investigate the effect of spacing between CFRP sheets, number of CFRP layers, and fiber orientation on the overall performance of the T-beam. It is concluded that successful FE modeling provides a practical and economical tool to investigate the behavior of such strengthened beams when subjected to cyclic loading.
|
토목공학
| null |
kci_detailed_000098.xml
|
|||
ART001544640
|
oai_dc
|
Finite element analysis of shear-critical reinforced concrete walls
|
Finite element analysis of shear-critical reinforced concrete walls
|
{
"journal_name": "국제구조공학회",
"publisher": null,
"pub_year": null,
"pub_month": null,
"volume": null,
"issue": null
}
|
[
"Ilker Kazaz(Atatürk University)"
] |
Advanced material models for concrete are not widely available in general purpose finite element codes. Parameters to define them complicate the implementation because they are case sensitive. In addition to this, their validity under severe shear condition has not been verified. In this article, simple engineering plasticity material models available in a commercial finite element code are used to demonstrate that complicated shear behavior can be calculated with reasonable accuracy. For this purpose dynamic response of a squat shear wall that had been tested on a shaking table as part of an experimental program conducted in Japan is analyzed. Both the finite element and material aspects of the modeling are examined. A corrective artifice for general engineering plasticity models to account for shear effects in concrete is developed. The results of modifications in modeling the concrete in compression are evaluated and compared with experimental response quantities.
|
토목공학
| null |
kci_detailed_000098.xml
|
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