Pub Date : 2021-01-01DOI: 10.12989/SCS.2021.40.4.621
S. Ghannadpour, F. Rashidi
Variable stiffness composite plate can adjust the stiffness properties of the plate in order to satisfy the design requirements of studied problem. In this paper, the effects of different types of boundary conditions, lay-ups, sizes and shapes of geometric initial imperfection on the nonlinear behavior of VAT plates are investigated; these conditions influence the behavior of the plate completely. Moreover, the first-order shear deformation plate theory and Von-Karman assumptions are applied to analyze the effects of fiber lay-up sequences of VAT-laminate under different boundary conditions. Ritz method is also exploited by using Legendre polynomials to approximate the unknown displacement fields of the problem. To yield more accurate results, potential energy integrals are numerically calculated by employing Gauss-Lobatto formulas. Lastly, the system of nonlinear equations is solved by the well-known Newton-Raphson technique. In order to validate the results, finite element analysis is also implemented by the commercial finite element package ABAQUS.
{"title":"A semi-analytical study on effects of geometric imperfection and curved fiber paths on nonlinear response of compression-loaded laminates","authors":"S. Ghannadpour, F. Rashidi","doi":"10.12989/SCS.2021.40.4.621","DOIUrl":"https://doi.org/10.12989/SCS.2021.40.4.621","url":null,"abstract":"Variable stiffness composite plate can adjust the stiffness properties of the plate in order to satisfy the design requirements of studied problem. In this paper, the effects of different types of boundary conditions, lay-ups, sizes and shapes of geometric initial imperfection on the nonlinear behavior of VAT plates are investigated; these conditions influence the behavior of the plate completely. Moreover, the first-order shear deformation plate theory and Von-Karman assumptions are applied to analyze the effects of fiber lay-up sequences of VAT-laminate under different boundary conditions. Ritz method is also exploited by using Legendre polynomials to approximate the unknown displacement fields of the problem. To yield more accurate results, potential energy integrals are numerically calculated by employing Gauss-Lobatto formulas. Lastly, the system of nonlinear equations is solved by the well-known Newton-Raphson technique. In order to validate the results, finite element analysis is also implemented by the commercial finite element package ABAQUS.","PeriodicalId":51177,"journal":{"name":"Steel and Composite Structures","volume":"40 1","pages":"621"},"PeriodicalIF":4.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66596203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SCS.2021.40.6.829
P. Lata, Iqbal Kaur, Kulvinder Singh
This investigation aims to examine the vibration phenomenon in 2D transversely isotropic homogeneous Euler-Bernoulli nonlocal nanobeam with laser pulse with new modified three-phase lag Green Naghdi (TPL GN) model. The model contains a material length scale parameter that can capture the size effect, using the nonlocal theory of thermoelasticity. Temperature is assumed to vary sinusoidally. Laplace Transforms are used to derive the non-dimensional expressions for lateral deflection, axial displacement, temperature distribution, axial stress, and thermal moment in the transformed domain, and numerical inversion techniques are used to find the expressions in the physical domain. The ends of the nanobeam are considered to be simply supported and have a constant temperature. Effect of new modified TPL GN heat transfer and nonlocal parameter is represented graphically for lateral deflection, axial displacement, temperature distribution, axial stress, and thermal moment using the MATLAB software. Few specific cases are also derived.
{"title":"Transversely isotropic Euler Bernoulli thermoelastic nanobeam with laser pulse and with modified three phase lag Green Nagdhi heat transfer","authors":"P. Lata, Iqbal Kaur, Kulvinder Singh","doi":"10.12989/SCS.2021.40.6.829","DOIUrl":"https://doi.org/10.12989/SCS.2021.40.6.829","url":null,"abstract":"This investigation aims to examine the vibration phenomenon in 2D transversely isotropic homogeneous Euler-Bernoulli nonlocal nanobeam with laser pulse with new modified three-phase lag Green Naghdi (TPL GN) model. The model contains a material length scale parameter that can capture the size effect, using the nonlocal theory of thermoelasticity. Temperature is assumed to vary sinusoidally. Laplace Transforms are used to derive the non-dimensional expressions for lateral deflection, axial displacement, temperature distribution, axial stress, and thermal moment in the transformed domain, and numerical inversion techniques are used to find the expressions in the physical domain. The ends of the nanobeam are considered to be simply supported and have a constant temperature. Effect of new modified TPL GN heat transfer and nonlocal parameter is represented graphically for lateral deflection, axial displacement, temperature distribution, axial stress, and thermal moment using the MATLAB software. Few specific cases are also derived.","PeriodicalId":51177,"journal":{"name":"Steel and Composite Structures","volume":"40 1","pages":"829"},"PeriodicalIF":4.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66596805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SCS.2021.39.3.243
S. Yaghmaei‐Sabegh, A. Jafari, M. Eghbali
In the present paper, a Monte Carlo-based framework is developed to investigate the accuracy and reliability of analytical fragility curves of steel moment-resisting frames and simple SDOF systems. It is also studied how the effectiveness of incremental dynamic analysis (IDA) and multiple stripes analysis (MSA) approaches, as two common nonlinear dynamic analysis methods, are influenced by the number of records and analysis stripes in fragility curves producing. Results showed that the simple SDOF systems do not provide accurate and reliable fragility curves compared with realistic steel moment-resisting structures. It is demonstrated that, the effectiveness of nonlinear dynamic analysis approaches is dependent on the fundamental period of structures, where in short-period structures, IDA is found to be more effective approach compared with MSA. This difference between the effectiveness of two analysis approaches decreases as the fundamental period of structures become longer. Using of 2 or 3 analysis stripes in MSA approach leads to significant inaccuracy and unreliability in the estimated fragility curves. Additionally, 15 number of ground motion records is recommended as a threshold of significant unreliability in estimated fragility curves, constructed by MSA.
{"title":"The accuracy of fragility curves of the steel moment-resisting frames and SDOF systems","authors":"S. Yaghmaei‐Sabegh, A. Jafari, M. Eghbali","doi":"10.12989/SCS.2021.39.3.243","DOIUrl":"https://doi.org/10.12989/SCS.2021.39.3.243","url":null,"abstract":"In the present paper, a Monte Carlo-based framework is developed to investigate the accuracy and reliability of analytical fragility curves of steel moment-resisting frames and simple SDOF systems. It is also studied how the effectiveness of incremental dynamic analysis (IDA) and multiple stripes analysis (MSA) approaches, as two common nonlinear dynamic analysis methods, are influenced by the number of records and analysis stripes in fragility curves producing. Results showed that the simple SDOF systems do not provide accurate and reliable fragility curves compared with realistic steel moment-resisting structures. It is demonstrated that, the effectiveness of nonlinear dynamic analysis approaches is dependent on the fundamental period of structures, where in short-period structures, IDA is found to be more effective approach compared with MSA. This difference between the effectiveness of two analysis approaches decreases as the fundamental period of structures become longer. Using of 2 or 3 analysis stripes in MSA approach leads to significant inaccuracy and unreliability in the estimated fragility curves. Additionally, 15 number of ground motion records is recommended as a threshold of significant unreliability in estimated fragility curves, constructed by MSA.","PeriodicalId":51177,"journal":{"name":"Steel and Composite Structures","volume":"9 1","pages":"243"},"PeriodicalIF":4.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66591706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SCS.2021.40.3.369
K. Ke, M. Yam, Xu-hong Zhou, Fuming Wang, Fei Xu
This investigation contributes to quantification of the inelastic seismic demands for high strength steel moment resisting frames equipped with energy dissipation bays (HSSF-EDBs) subjected to seismic sequences composed of repeated near-field ground motions. The emphasis is placed on the energy factor demand. A statistical examination of a database with more than eighty million energy factor demands of single-degree-of-freedom (SDOF) oscillators representing HSSF-EDBs responding in different yielding stages is conducted. The research findings show that in the damage-control stage, the energy factor which quantifies the peak seismic demand of a HSSF-EDB structure is insensitive to the repeated near-field earthquake motions. In contrast, a remarkable elevation of the energy factor is observed when oscillators characterising HSSF-EDBs progress into the ultimate stage. In addition, an increasing post-yielding stiffness ratio of the nonlinear force-displacement response in the damage-control stage may produce a detrimental effect on HSSF-EDBs progressing into the ultimate stage under repeated near-field earthquakes due to the corresponding evident increase of seismic demands. A nonlinear regression model quantifying the mean energy factor demand of the system under repeated near-field earthquake motions is proposed to facilitate performance-based seismic design of HSSF-EDBs.
{"title":"Energy factor of high-strength-steel frames with energy dissipation bays under repeated near-field earthquakes","authors":"K. Ke, M. Yam, Xu-hong Zhou, Fuming Wang, Fei Xu","doi":"10.12989/SCS.2021.40.3.369","DOIUrl":"https://doi.org/10.12989/SCS.2021.40.3.369","url":null,"abstract":"This investigation contributes to quantification of the inelastic seismic demands for high strength steel moment resisting frames equipped with energy dissipation bays (HSSF-EDBs) subjected to seismic sequences composed of repeated near-field ground motions. The emphasis is placed on the energy factor demand. A statistical examination of a database with more than eighty million energy factor demands of single-degree-of-freedom (SDOF) oscillators representing HSSF-EDBs responding in different yielding stages is conducted. The research findings show that in the damage-control stage, the energy factor which quantifies the peak seismic demand of a HSSF-EDB structure is insensitive to the repeated near-field earthquake motions. In contrast, a remarkable elevation of the energy factor is observed when oscillators characterising HSSF-EDBs progress into the ultimate stage. In addition, an increasing post-yielding stiffness ratio of the nonlinear force-displacement response in the damage-control stage may produce a detrimental effect on HSSF-EDBs progressing into the ultimate stage under repeated near-field earthquakes due to the corresponding evident increase of seismic demands. A nonlinear regression model quantifying the mean energy factor demand of the system under repeated near-field earthquake motions is proposed to facilitate performance-based seismic design of HSSF-EDBs.","PeriodicalId":51177,"journal":{"name":"Steel and Composite Structures","volume":"40 1","pages":"369"},"PeriodicalIF":4.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66595015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SCS.2021.38.2.213
P. Lata, Harpreet Kaur
The objective of this paper is to study the deformation in a homogeneous isotropic thermoelastic solid using modified couple stress theory subjected to ramp-type thermal source with two temperature. The advantage of this theory is the involvement of only one material length scale parameter which can determine the size effects. Laplace and Fourier transform technique is applied to obtain the solutions of the governing equations. The components of displacement, conductive temperature, stress components and couple stress are obtained in the transformed domain. A numerical inversion technique has been used to obtain the solutions in the physical domain. The effect of two temperature is depicted graphically on the resulted quantities. Numerical results show that the proposed model can capture the size effects of microstructures.
{"title":"Interactions in a homogeneous isotropic modified couple stress thermoelastic solid with multi-dual-phase-lag heat transfer and two temperature","authors":"P. Lata, Harpreet Kaur","doi":"10.12989/SCS.2021.38.2.213","DOIUrl":"https://doi.org/10.12989/SCS.2021.38.2.213","url":null,"abstract":"The objective of this paper is to study the deformation in a homogeneous isotropic thermoelastic solid using modified couple stress theory subjected to ramp-type thermal source with two temperature. The advantage of this theory is the involvement of only one material length scale parameter which can determine the size effects. Laplace and Fourier transform technique is applied to obtain the solutions of the governing equations. The components of displacement, conductive temperature, stress components and couple stress are obtained in the transformed domain. A numerical inversion technique has been used to obtain the solutions in the physical domain. The effect of two temperature is depicted graphically on the resulted quantities. Numerical results show that the proposed model can capture the size effects of microstructures.","PeriodicalId":51177,"journal":{"name":"Steel and Composite Structures","volume":"38 1","pages":"213-221"},"PeriodicalIF":4.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66589481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SCS.2021.38.1.087
Junli Lyu, Zhou Shengnan, Chen Qichao, Yong Wang
To investigate the failure form, bending stiffness, and residual bearing capacity of monolithic composite beams with laminated slab throughout the fire process, fire tests of four monolithic composite beams with laminated slab were performed under constant load and temperature increase. Different factors such as post-pouring layer thickness, lap length of the prefabricated bottom slab, and stud spacing were considered in the fire test. The test results demonstrate that, under the same fire time and external load, the post-pouring layer thickness and stud spacing are important parameters that affect the fire resistance of monolithic composite beams with laminated slab. Similarly, the post-pouring layer thickness and stud spacing are the predominant factors affecting the bending stiffness of monolithic composite beams with laminated slab after fire exposure. The failure forms of monolithic composite beams with laminated slab after the fire are approximately the same as those at room temperature. In both cases, the beams underwent bending failure. However, after exposure to the high-temperature fire, cracks appeared earlier in the monolithic composite beams with laminated slab, and both the residual bearing capacity and bending stiffness were reduced by varying degrees. In this test, the bending bearing capacity and ductility of monolithic composite beams with laminated slab after fire exposure were reduced by 23.3% and 55.4%, respectively, compared with those tested at room temperature. Calculation methods for the residual bearing capacity and bending stiffness of monolithic composite beams with laminated slab in and after the fire are proposed, which demonstrated good accuracy.
{"title":"The bearing capacity of monolithic composite beams with laminated slab throughout fire process","authors":"Junli Lyu, Zhou Shengnan, Chen Qichao, Yong Wang","doi":"10.12989/SCS.2021.38.1.087","DOIUrl":"https://doi.org/10.12989/SCS.2021.38.1.087","url":null,"abstract":"To investigate the failure form, bending stiffness, and residual bearing capacity of monolithic composite beams with laminated slab throughout the fire process, fire tests of four monolithic composite beams with laminated slab were performed under constant load and temperature increase. Different factors such as post-pouring layer thickness, lap length of the prefabricated bottom slab, and stud spacing were considered in the fire test. The test results demonstrate that, under the same fire time and external load, the post-pouring layer thickness and stud spacing are important parameters that affect the fire resistance of monolithic composite beams with laminated slab. Similarly, the post-pouring layer thickness and stud spacing are the predominant factors affecting the bending stiffness of monolithic composite beams with laminated slab after fire exposure. The failure forms of monolithic composite beams with laminated slab after the fire are approximately the same as those at room temperature. In both cases, the beams underwent bending failure. However, after exposure to the high-temperature fire, cracks appeared earlier in the monolithic composite beams with laminated slab, and both the residual bearing capacity and bending stiffness were reduced by varying degrees. In this test, the bending bearing capacity and ductility of monolithic composite beams with laminated slab after fire exposure were reduced by 23.3% and 55.4%, respectively, compared with those tested at room temperature. Calculation methods for the residual bearing capacity and bending stiffness of monolithic composite beams with laminated slab in and after the fire are proposed, which demonstrated good accuracy.","PeriodicalId":51177,"journal":{"name":"Steel and Composite Structures","volume":"38 1","pages":"87-102"},"PeriodicalIF":4.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66588407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SCS.2021.38.2.177
A. Fattahi, B. Safaei, Zhao-ye Qin, F. Chu
The effect of nanoparticle volume fraction on the elastic properties of a polymer-based nanocomposite was experimentally investigated and the obtained results were compared with various existing theoretical models. The nanocomposite was consisted of high density polyethylene (HDPE) as polymeric matrix and 0, 0.5, 1 and 1.5 wt.% multi walled carbon nanotubes (MWCNTs) prepared using twin screw extruder and injection molding technique. Nanocomposite samples were molded in injection apparatus according to ASTM-D638 standard. Therefore, in addition to morphological investigations of the samples, tensile tests at ambient temperature were performed on each sample and stress-strain plots, elastic moduli, Poisson's ratios, and strain energies of volume units were extracted from primary strain test results. Tensile test results demonstrated that 1 wt.% nanoparticles presented the best reinforcement behavior in HDPE-MWCNT nanocomposites. Due to the agglomeration of nanoparticles at above 1 wt.%, Young' s modulus, yielding stress, fracture stress, and fracture energy were decreased and Poisson's ratio and failure strain were increased.
{"title":"Experimental studies on elastic properties of high density polyethylene-multi walled carbon nanotube nanocomposites","authors":"A. Fattahi, B. Safaei, Zhao-ye Qin, F. Chu","doi":"10.12989/SCS.2021.38.2.177","DOIUrl":"https://doi.org/10.12989/SCS.2021.38.2.177","url":null,"abstract":"The effect of nanoparticle volume fraction on the elastic properties of a polymer-based nanocomposite was experimentally investigated and the obtained results were compared with various existing theoretical models. The nanocomposite was consisted of high density polyethylene (HDPE) as polymeric matrix and 0, 0.5, 1 and 1.5 wt.% multi walled carbon nanotubes (MWCNTs) prepared using twin screw extruder and injection molding technique. Nanocomposite samples were molded in injection apparatus according to ASTM-D638 standard. Therefore, in addition to morphological investigations of the samples, tensile tests at ambient temperature were performed on each sample and stress-strain plots, elastic moduli, Poisson's ratios, and strain energies of volume units were extracted from primary strain test results. Tensile test results demonstrated that 1 wt.% nanoparticles presented the best reinforcement behavior in HDPE-MWCNT nanocomposites. Due to the agglomeration of nanoparticles at above 1 wt.%, Young' s modulus, yielding stress, fracture stress, and fracture energy were decreased and Poisson's ratio and failure strain were increased.","PeriodicalId":51177,"journal":{"name":"Steel and Composite Structures","volume":"38 1","pages":"177-187"},"PeriodicalIF":4.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66588668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SCS.2021.38.4.381
Tengfei Li, M. Su, Jiangran Guo
{"title":"Hybrid simulation tests of high-strength steel composite K-eccentrically braced frames with spatial substructure","authors":"Tengfei Li, M. Su, Jiangran Guo","doi":"10.12989/SCS.2021.38.4.381","DOIUrl":"https://doi.org/10.12989/SCS.2021.38.4.381","url":null,"abstract":"","PeriodicalId":51177,"journal":{"name":"Steel and Composite Structures","volume":"38 1","pages":"381-397"},"PeriodicalIF":4.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66589695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SCS.2021.38.5.497
V. Bui, Q. Vu, V. Truong, Seung-Eock Kim
In this study, an effective numerical method is introduced for nonlinear inelastic analyses of rectangular concrete-filled steel tubular (CFST) frames for the first time. A steel-concrete composite fiber beam-column element model is developed that considers material, and geometric nonlinearities, and residual stresses. This is achieved by using stability functions combined with integration points along the element length to capture the spread of plasticity over the composite cross-section along the element length. Additionally, a multi-spring element with a zero-length is employed to model the nonlinear semi-rigid beam-to-column connections in CFST frame models. To solve the nonlinear equilibrium equations, the generalized displacement control algorithm is adopted. The accuracy of the proposed method is firstly verified by a large number of experiments of CFST members subjected to various loading conditions. Subsequently, the proposed method is applied to investigate the nonlinear inelastic behavior of rectangular CFST frames with fully rigid, semi-rigid, and hinged connections. The accuracy of the predicted results and the efficiency pertaining to the computation time of the proposed method are demonstrated in comparison with the ABAQUS software. The proposed numerical method may be efficiently utilized in practical designs for advanced analysis of the rectangular CFST structures.
{"title":"Fully nonlinear inelastic analysis of rectangular CFST frames with semi-rigid connections","authors":"V. Bui, Q. Vu, V. Truong, Seung-Eock Kim","doi":"10.12989/SCS.2021.38.5.497","DOIUrl":"https://doi.org/10.12989/SCS.2021.38.5.497","url":null,"abstract":"In this study, an effective numerical method is introduced for nonlinear inelastic analyses of rectangular concrete-filled steel tubular (CFST) frames for the first time. A steel-concrete composite fiber beam-column element model is developed that considers material, and geometric nonlinearities, and residual stresses. This is achieved by using stability functions combined with integration points along the element length to capture the spread of plasticity over the composite cross-section along the element length. Additionally, a multi-spring element with a zero-length is employed to model the nonlinear semi-rigid beam-to-column connections in CFST frame models. To solve the nonlinear equilibrium equations, the generalized displacement control algorithm is adopted. The accuracy of the proposed method is firstly verified by a large number of experiments of CFST members subjected to various loading conditions. Subsequently, the proposed method is applied to investigate the nonlinear inelastic behavior of rectangular CFST frames with fully rigid, semi-rigid, and hinged connections. The accuracy of the predicted results and the efficiency pertaining to the computation time of the proposed method are demonstrated in comparison with the ABAQUS software. The proposed numerical method may be efficiently utilized in practical designs for advanced analysis of the rectangular CFST structures.","PeriodicalId":51177,"journal":{"name":"Steel and Composite Structures","volume":"38 1","pages":"497-521"},"PeriodicalIF":4.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66590014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.12989/SCS.2021.38.6.657
Li Xuyang, Gang Zhang, V. Kodur, Shuanhai He, Qiao Huang
This paper presents a designing method for enhancing fire resistance of steel box bridge girders (closed steel box bridge girder supporting a thin concrete slab) through taking into account such parameters namely; fire severity, type of longitudinal stiffeners (I, L, and T shaped), and number of longitudinal stiffeners. A validated 3-D finite element model, developed through the computer program ANSYS, is utilized to go over the fire response of a typical steel box bridge girder using the transient thermo-structural analysis method. Results from the numerical analysis show that fire severity and type of longitudinal stiffeners welded on bottom flange have significant influence on fire resistance of steel box bridge girders. T shaped longitudinal stiffeners applied on bottom flange can highly prevent collapse of steel box bridge girders towards the end of fire exposure. Increase of longitudinal stiffeners on bottom flange and web can slightly enhance fire resistance of steel box bridge girders. Rate of deflection-based criterion can be reliable to evaluate fire resistance of steel box bridge girders in most fire exposure cases. Thus, T shaped longitudinal stiffeners on bottom flange incorporated into bridge fire-resistance design can significantly enhance fire resistance of steel box bridge girders.
{"title":"Designing method for fire safety of steel box bridge girders","authors":"Li Xuyang, Gang Zhang, V. Kodur, Shuanhai He, Qiao Huang","doi":"10.12989/SCS.2021.38.6.657","DOIUrl":"https://doi.org/10.12989/SCS.2021.38.6.657","url":null,"abstract":"This paper presents a designing method for enhancing fire resistance of steel box bridge girders (closed steel box bridge girder supporting a thin concrete slab) through taking into account such parameters namely; fire severity, type of longitudinal stiffeners (I, L, and T shaped), and number of longitudinal stiffeners. A validated 3-D finite element model, developed through the computer program ANSYS, is utilized to go over the fire response of a typical steel box bridge girder using the transient thermo-structural analysis method. Results from the numerical analysis show that fire severity and type of longitudinal stiffeners welded on bottom flange have significant influence on fire resistance of steel box bridge girders. T shaped longitudinal stiffeners applied on bottom flange can highly prevent collapse of steel box bridge girders towards the end of fire exposure. Increase of longitudinal stiffeners on bottom flange and web can slightly enhance fire resistance of steel box bridge girders. Rate of deflection-based criterion can be reliable to evaluate fire resistance of steel box bridge girders in most fire exposure cases. Thus, T shaped longitudinal stiffeners on bottom flange incorporated into bridge fire-resistance design can significantly enhance fire resistance of steel box bridge girders.","PeriodicalId":51177,"journal":{"name":"Steel and Composite Structures","volume":"53 1","pages":"657"},"PeriodicalIF":4.6,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66590280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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