Pub Date : 2024-09-07DOI: 10.1016/j.istruc.2024.107232
Haiping Zhang, Hao Long, Fanghuai Chen, Yuan Luo, Xinhui Xiao, Yang Deng, Naiwei Lu, Yang Liu
Due to the significant difference in specific heat capacity between concrete materials and steel, the prestressed concrete (PC) beam bridge with corrugated steel webs (CSWs) exhibits considerable non-uniform temperature fields under the combined effects of solar radiation, ambient temperature, and wind speed. To elucidate the distribution characteristics of non-uniform temperature fields in PC beam bridges with CSWs in service and improve the computational efficiency of temperature fields, this study proposes an efficient solution method for structural temperature fields based on the Back Propagation (BP) neural network. In this paper, a numerical model is established to simulate the heat conduction, radiation, and convection processes in PC beam bridges with CSWs. The temperature field characteristics of the box girder structure under the combined influence of solar radiation intensity, air temperature, and wind speed are analyzed and validated against measured data. Based on this, a BP neural network surrogate model is constructed to rapidly and accurately solve the temperature field of corrugated steel web PC girder bridges. The research results indicate that the BP neural network structure exhibits minimal errors between the predicted and actual temperatures of steel plates and concrete in composite girder bridges. The average coefficient of determination is 0.9985, indicating that the temperature prediction for concrete is superior to that for steel structures.
由于混凝土材料与钢材的比热容存在显著差异，在太阳辐射、环境温度和风速的共同作用下，带波纹钢腹板（CSW）的预应力混凝土（PC）梁桥表现出相当大的非均匀温度场。为阐明带波纹钢腹板 PC 梁桥非均匀温度场的分布特征，提高温度场的计算效率，本研究提出了一种基于反向传播（BP）神经网络的结构温度场高效求解方法。本文建立了一个数值模型来模拟带 CSW 的 PC 梁桥的热传导、辐射和对流过程。分析了箱梁结构在太阳辐射强度、空气温度和风速共同影响下的温度场特征，并根据测量数据进行了验证。在此基础上，构建了一个 BP 神经网络代用模型，用于快速准确地求解波形钢腹板 PC 梁桥的温度场。研究结果表明，BP 神经网络结构在复合梁桥钢板和混凝土的预测温度与实际温度之间的误差极小。平均判定系数为 0.9985，表明对混凝土的温度预测优于对钢结构的预测。
{"title":"Temperature field prediction for a PC beam bridge with corrugated steel webs using BP neural network and measured data","authors":"Haiping Zhang, Hao Long, Fanghuai Chen, Yuan Luo, Xinhui Xiao, Yang Deng, Naiwei Lu, Yang Liu","doi":"10.1016/j.istruc.2024.107232","DOIUrl":"https://doi.org/10.1016/j.istruc.2024.107232","url":null,"abstract":"Due to the significant difference in specific heat capacity between concrete materials and steel, the prestressed concrete (PC) beam bridge with corrugated steel webs (CSWs) exhibits considerable non-uniform temperature fields under the combined effects of solar radiation, ambient temperature, and wind speed. To elucidate the distribution characteristics of non-uniform temperature fields in PC beam bridges with CSWs in service and improve the computational efficiency of temperature fields, this study proposes an efficient solution method for structural temperature fields based on the Back Propagation (BP) neural network. In this paper, a numerical model is established to simulate the heat conduction, radiation, and convection processes in PC beam bridges with CSWs. The temperature field characteristics of the box girder structure under the combined influence of solar radiation intensity, air temperature, and wind speed are analyzed and validated against measured data. Based on this, a BP neural network surrogate model is constructed to rapidly and accurately solve the temperature field of corrugated steel web PC girder bridges. The research results indicate that the BP neural network structure exhibits minimal errors between the predicted and actual temperatures of steel plates and concrete in composite girder bridges. The average coefficient of determination is 0.9985, indicating that the temperature prediction for concrete is superior to that for steel structures.","PeriodicalId":48642,"journal":{"name":"Structures","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-06DOI: 10.1016/j.istruc.2024.107227
Ahmed Manguri, Najmadeen Saeed, Robert Jankowski
Over the last five decades, space frames have centered on the modernization of touristic zones in view of architectural attractions. Although attempts to control joint movement and minimize axial force and bending moment in such structures were made sufficiently, twisting moments in space frames have been underestimated so far. In space frames, external load or restoring the misshapen shape may cause twisting in members. We herein developed a robust computational algorithm to reduce the induced torsional moment through shape restoration within a desired limit by changing the length of active bars that are placed in space frames. Applying optimization algorithms like interior-point and Sequential quadratic programming (SQP), a direct correlation was pursued between bar length alteration and twisting in structural members. A numerical model of a single-layer space frame resembling an egg captures the twisting moment in all members, achieving a specified limit. The overall length change of the active members using an iterative process based on a heuristic that considers a threshold on the minimum length change of the active members.
{"title":"Deformation mitigation and twisting moment control in space frames","authors":"Ahmed Manguri, Najmadeen Saeed, Robert Jankowski","doi":"10.1016/j.istruc.2024.107227","DOIUrl":"https://doi.org/10.1016/j.istruc.2024.107227","url":null,"abstract":"Over the last five decades, space frames have centered on the modernization of touristic zones in view of architectural attractions. Although attempts to control joint movement and minimize axial force and bending moment in such structures were made sufficiently, twisting moments in space frames have been underestimated so far. In space frames, external load or restoring the misshapen shape may cause twisting in members. We herein developed a robust computational algorithm to reduce the induced torsional moment through shape restoration within a desired limit by changing the length of active bars that are placed in space frames. Applying optimization algorithms like interior-point and Sequential quadratic programming (SQP), a direct correlation was pursued between bar length alteration and twisting in structural members. A numerical model of a single-layer space frame resembling an egg captures the twisting moment in all members, achieving a specified limit. The overall length change of the active members using an iterative process based on a heuristic that considers a threshold on the minimum length change of the active members.","PeriodicalId":48642,"journal":{"name":"Structures","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The overlap between high-speed railways and earthquake areas makes it necessary to implement isolation design for railway bridges. At present, the variation of seismic energy of railway bridges with structural and ground motion parameters is not clear. In this paper, the finite element models of railway bridges with different pier heights are established and verified by shaking table tests. Then, the nonlinear time history analysis of isolated and non-isolated models is carried out, and the differences in seismic response and energy dissipation between the two models under different parameters are compared. Finally, the isolation effect of hyperbolic friction pendulum bearing (HFPB) is evaluated by using the efficacy coefficient method. Results demonstrate that HFPB can not only reduce the seismic response of the girder and the pier, but also effectively reduce the seismic input energy, structural damping energy, and pier hysteretic energy. In addition, HFPB has a better seismic isolation effect when pier height is 3–15 m, site characteristic period is 0.25–0.45 s, and earthquake PGA is 0.2–0.5 g.
{"title":"Influence of pier height and ground motion parameters on seismic response and energy dissipation of isolated railway bridges","authors":"Hao Tan, Biao Wei, Weihao Wang, Binqi Xiao, Shanshan Li, Lizhong Jiang","doi":"10.1016/j.istruc.2024.107236","DOIUrl":"https://doi.org/10.1016/j.istruc.2024.107236","url":null,"abstract":"The overlap between high-speed railways and earthquake areas makes it necessary to implement isolation design for railway bridges. At present, the variation of seismic energy of railway bridges with structural and ground motion parameters is not clear. In this paper, the finite element models of railway bridges with different pier heights are established and verified by shaking table tests. Then, the nonlinear time history analysis of isolated and non-isolated models is carried out, and the differences in seismic response and energy dissipation between the two models under different parameters are compared. Finally, the isolation effect of hyperbolic friction pendulum bearing (HFPB) is evaluated by using the efficacy coefficient method. Results demonstrate that HFPB can not only reduce the seismic response of the girder and the pier, but also effectively reduce the seismic input energy, structural damping energy, and pier hysteretic energy. In addition, HFPB has a better seismic isolation effect when pier height is 3–15 m, site characteristic period is 0.25–0.45 s, and earthquake PGA is 0.2–0.5 g.","PeriodicalId":48642,"journal":{"name":"Structures","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-06DOI: 10.1016/j.istruc.2024.107194
Chao Hu, Yuhang Wang, Rui Cheng, Jun Luo, Meilan Gong
In recent years, there has been a notable surge in proposals for various forms of special-shaped concrete-filled steel tubular (CFST) columns. Despite various methods developed by researchers for determining the bearing capacity of multi-cell special-shaped CFST columns under different loading conditions, these methods remain lack unified. In this study, FE models were developed to simulate performances of improved multi-cell L-shaped CFST (ML-CFST) column under compression and bending. Parametric analyses have been performed to evaluate impact of various factors, including steel yield strength , compressive strength of concrete , steel thickness , loading direction , web height , and axial load ratio , on performances of ML-CFST columns. The findings of study indicate that the unidirectional flexural capacity of ML-CFST member exhibits a nearly linear relationship with the variables of , , and , with a minimal impact observed from on flexural capacity. The width of extended section , , , and have a certain effect on flexural capacity at any angle, particularly , and . While , , and exert some influence on /-/ correlation curves, their influences are marginal compared to the loading direction, which is the predominant influencing factor. Additionally, /-/ curves gradually protrude outward with the increase in . The effects of , , and on the shape of /-/ curve were relatively insignificant. Simplified unidirectional flexural capacity calculation models were proposed based on stress analysis of cross-section under ultimate states. Given that flexural capacities estimated by simplified calculation model are slightly conservative, it is recommended to increase the flexural capacities by 10 %. Furthermore, an elliptical equation was formulated to predict the flexural capacity at any angle, with the predictions being slightly conservative. Based on ultimate equilibrium theory, a simplified calculation method was presented to predict unidirectional eccentric bearing capacities of ML-CFST columns. Through regression analysis, a simplified calculation method expressed as polar coordinate form for biaxial eccentric bearing capacity was established, with calculated values aligning well with FE results.
{"title":"Design of improved multi-cell L-shaped CFST columns under compression and bending","authors":"Chao Hu, Yuhang Wang, Rui Cheng, Jun Luo, Meilan Gong","doi":"10.1016/j.istruc.2024.107194","DOIUrl":"https://doi.org/10.1016/j.istruc.2024.107194","url":null,"abstract":"In recent years, there has been a notable surge in proposals for various forms of special-shaped concrete-filled steel tubular (CFST) columns. Despite various methods developed by researchers for determining the bearing capacity of multi-cell special-shaped CFST columns under different loading conditions, these methods remain lack unified. In this study, FE models were developed to simulate performances of improved multi-cell L-shaped CFST (ML-CFST) column under compression and bending. Parametric analyses have been performed to evaluate impact of various factors, including steel yield strength , compressive strength of concrete , steel thickness , loading direction , web height , and axial load ratio , on performances of ML-CFST columns. The findings of study indicate that the unidirectional flexural capacity of ML-CFST member exhibits a nearly linear relationship with the variables of , , and , with a minimal impact observed from on flexural capacity. The width of extended section , , , and have a certain effect on flexural capacity at any angle, particularly , and . While , , and exert some influence on /-/ correlation curves, their influences are marginal compared to the loading direction, which is the predominant influencing factor. Additionally, /-/ curves gradually protrude outward with the increase in . The effects of , , and on the shape of /-/ curve were relatively insignificant. Simplified unidirectional flexural capacity calculation models were proposed based on stress analysis of cross-section under ultimate states. Given that flexural capacities estimated by simplified calculation model are slightly conservative, it is recommended to increase the flexural capacities by 10 %. Furthermore, an elliptical equation was formulated to predict the flexural capacity at any angle, with the predictions being slightly conservative. Based on ultimate equilibrium theory, a simplified calculation method was presented to predict unidirectional eccentric bearing capacities of ML-CFST columns. Through regression analysis, a simplified calculation method expressed as polar coordinate form for biaxial eccentric bearing capacity was established, with calculated values aligning well with FE results.","PeriodicalId":48642,"journal":{"name":"Structures","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-06DOI: 10.1016/j.istruc.2024.107230
Jinyou Zhao, Jin Li, Paddy McDermott, Jie Wang, Xi Chen, Yao Sun
This paper presents testing and modelling investigations on the global stability and load-carrying capacities of S460 high-strength steel mono-symmetric welded I-section beams susceptible to lateral-torsional buckling. A testing programme was firstly carried out, including material coupon tests, imperfection measurements and mono-symmetric welded I-section beam tests. Upon completion of the testing programme, a numerical modelling programme was conducted, where finite-element models were developed and validated. The numerical models were then used to perform parametric studies to obtain additional beam data. The obtained test and numerical data were afterwards adopted to conduct a design analysis, where the relevant design rules given in the European, American and Chinese standards were assessed. The assessment results indicated the excessive design conservatism of the European and Chinese codified buckling curves, while the American standard resulted in many unsafe resistance predictions. Finally, an improved design approach was proposed to offer better design accuracy and consistency.
{"title":"Global stability of mono-symmetric I-section high-strength steel beams","authors":"Jinyou Zhao, Jin Li, Paddy McDermott, Jie Wang, Xi Chen, Yao Sun","doi":"10.1016/j.istruc.2024.107230","DOIUrl":"https://doi.org/10.1016/j.istruc.2024.107230","url":null,"abstract":"This paper presents testing and modelling investigations on the global stability and load-carrying capacities of S460 high-strength steel mono-symmetric welded I-section beams susceptible to lateral-torsional buckling. A testing programme was firstly carried out, including material coupon tests, imperfection measurements and mono-symmetric welded I-section beam tests. Upon completion of the testing programme, a numerical modelling programme was conducted, where finite-element models were developed and validated. The numerical models were then used to perform parametric studies to obtain additional beam data. The obtained test and numerical data were afterwards adopted to conduct a design analysis, where the relevant design rules given in the European, American and Chinese standards were assessed. The assessment results indicated the excessive design conservatism of the European and Chinese codified buckling curves, while the American standard resulted in many unsafe resistance predictions. Finally, an improved design approach was proposed to offer better design accuracy and consistency.","PeriodicalId":48642,"journal":{"name":"Structures","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-06DOI: 10.1016/j.istruc.2024.107131
Peng Wang, Jie Huang, Yi Tao, Qingxuan Shi, Bin Wang
To investigate the shear behavior of composite beams with a UHPC stay-in-place formwork, seven composite beam specimens with a UHPC stay-in-place formwork (URB) and one reference specimen for normal reinforced concrete (RC) beam were designed in this paper. An experimental study was conducted to investigate the shear behavior of composite beams with a UHPC stay-in-place formwork under static loading. The research parameters included shear-span ratio, transverse rib spacing, and stirrup ratio. The results indicated that UHPC stay-in-place formwork can effectively improve the stiffness, cracking resistance, and shear resistance of members. Compared with the RC beam, the shear load when the first bending crack appeared () and the shear load when the first shear diagonal crack appeared () of composite beams increased by 328 % ∼ 422 % and 175 % ∼ 206 %, the stiffness when the first bending crack appeared () and the stiffness when the first shear diagonal crack appeared () increased by 30.3 % ∼ 44.8 % and 4.9 % ∼ 36.0 %, respectively, and the shear bearing capacity increased by 72 % ∼ 89 %. The shear bearing capacity of composite beams increased significantly with the decrease of shear-span ratio. The increase in stirrup ratio had an improvement in the shear bearing capacity of composite beams, but had a small impact on the cracking resistance. The decrease in spacing of transverse ribs did not yield a substantial increase in shear bearing capacity for composite beams. Nonetheless, the difference between (ultimate shear bearing capacity) and exhibited an obvious increasing trend, suggesting an enhancement in cracking resistance. The interface treatment method of setting transverse ribs improved the integrity of the composite beam and avoided longitudinal interface separation between the formwork and the core concrete. The presence of steel fibers effectively inhibited crack development through their bridging action. Finally, the calculation model of shear bearing capacity of composite beams with a UHPC stay-in-place formwork is established based on the truss-arch model. The average ratio of the calculated value to the experimental value is 0.99, with a coefficient of variation of 0.06. The theoretical calculated are in good agreement with the experimental results.
{"title":"Shear behavior and bearing capacity of reinforced concrete beams with a UHPC stay-in-place formwork","authors":"Peng Wang, Jie Huang, Yi Tao, Qingxuan Shi, Bin Wang","doi":"10.1016/j.istruc.2024.107131","DOIUrl":"https://doi.org/10.1016/j.istruc.2024.107131","url":null,"abstract":"To investigate the shear behavior of composite beams with a UHPC stay-in-place formwork, seven composite beam specimens with a UHPC stay-in-place formwork (URB) and one reference specimen for normal reinforced concrete (RC) beam were designed in this paper. An experimental study was conducted to investigate the shear behavior of composite beams with a UHPC stay-in-place formwork under static loading. The research parameters included shear-span ratio, transverse rib spacing, and stirrup ratio. The results indicated that UHPC stay-in-place formwork can effectively improve the stiffness, cracking resistance, and shear resistance of members. Compared with the RC beam, the shear load when the first bending crack appeared () and the shear load when the first shear diagonal crack appeared () of composite beams increased by 328 % ∼ 422 % and 175 % ∼ 206 %, the stiffness when the first bending crack appeared () and the stiffness when the first shear diagonal crack appeared () increased by 30.3 % ∼ 44.8 % and 4.9 % ∼ 36.0 %, respectively, and the shear bearing capacity increased by 72 % ∼ 89 %. The shear bearing capacity of composite beams increased significantly with the decrease of shear-span ratio. The increase in stirrup ratio had an improvement in the shear bearing capacity of composite beams, but had a small impact on the cracking resistance. The decrease in spacing of transverse ribs did not yield a substantial increase in shear bearing capacity for composite beams. Nonetheless, the difference between (ultimate shear bearing capacity) and exhibited an obvious increasing trend, suggesting an enhancement in cracking resistance. The interface treatment method of setting transverse ribs improved the integrity of the composite beam and avoided longitudinal interface separation between the formwork and the core concrete. The presence of steel fibers effectively inhibited crack development through their bridging action. Finally, the calculation model of shear bearing capacity of composite beams with a UHPC stay-in-place formwork is established based on the truss-arch model. The average ratio of the calculated value to the experimental value is 0.99, with a coefficient of variation of 0.06. The theoretical calculated are in good agreement with the experimental results.","PeriodicalId":48642,"journal":{"name":"Structures","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
High-speed railway track-bridge systems (HSRTBSs) are subject to rigorous safety performance criteria. Components within the bridge and track structures, such as bearings and CA mortal layer, are susceptible to severe damage during earthquakes, probably compromising running safety. An available way to control seismic response is installing damping devices. However, few research focuses on the contribution of dampers to response of HSRTBS considering train effects. This paper delineates the development of a finite element model of a five-span simply-supported HSRTBS, augmented with prefabricated and modularized U-shaped combined steel dampers (UCSDs), via OpenSees. A high-speed train, running on the HSRBTS, is simulated through the moving spring mass column method (MSMCM). An innovative index, damage dispersion (), is proposed based on the seismic fragility analysis of two groups of components, categorized by their relative fragility in the HSRBTS, to probabilistically assess the impact of the dampers on seismic damage distribution among the system. The result shows that the UCSDs effectively disperse damage from more vulnerable components (fixed bearings, sliding layers, and CA mortar layers) to stronger ones (piers and fasteners). The observed decrease in the median and standard deviation of , identified as a logarithmic normal distribution, implies that UCSDs contribute to a more uniform damage distribution across the system, even when train effects are considered. The variation trend of with PGA shifts from an increase to a modest decline, and the values of exhibit a systematic reduction after considering train running, partially attributable to the train bogies in dissipating energy.
高速铁路轨道桥梁系统（HSRTBSs）必须符合严格的安全性能标准。桥梁和轨道结构中的部件，如支座和 CA 防震层，在地震中很容易受到严重破坏，从而影响运行安全。安装阻尼装置是控制地震响应的一种可用方法。然而，考虑到列车效应，很少有研究关注阻尼器对 HSRTBS 响应的贡献。本文通过 OpenSees 描述了五跨简单支撑 HSRTBS 有限元模型的开发过程，该模型安装了预制和模块化 U 型组合钢阻尼器 (UCSD)。在 HSRBTS 上运行的高速列车通过移动弹簧质量柱法 (MSMCM) 进行模拟。根据两组部件的地震脆性分析（按其在 HSRBTS 中的相对脆性分类），提出了一个创新指标--损伤分散（），以概率评估阻尼器对系统中地震损伤分布的影响。结果表明，UCSDs 有效地将破坏从较脆弱的构件（固定支座、滑动层和 CA 砂浆层）分散到较坚固的构件（桥墩和紧固件）。在对数正态分布中观察到的中位数和标准偏差的减少，意味着即使考虑列车效应，UCSD 也能使整个系统的损坏分布更加均匀。PGA 的变化趋势从上升转为小幅下降，在考虑列车运行后，PGA 的值呈现系统性下降，部分原因是列车转向架在耗散能量。
{"title":"Damage dispersion study of high-speed railway track-bridge system with the UCSD considering train effects","authors":"Liqiang Jiang, Juntao Liu, Tianxing Wen, Lizhong Jiang, Yingqi Yan, Chang He","doi":"10.1016/j.istruc.2024.107213","DOIUrl":"https://doi.org/10.1016/j.istruc.2024.107213","url":null,"abstract":"High-speed railway track-bridge systems (HSRTBSs) are subject to rigorous safety performance criteria. Components within the bridge and track structures, such as bearings and CA mortal layer, are susceptible to severe damage during earthquakes, probably compromising running safety. An available way to control seismic response is installing damping devices. However, few research focuses on the contribution of dampers to response of HSRTBS considering train effects. This paper delineates the development of a finite element model of a five-span simply-supported HSRTBS, augmented with prefabricated and modularized U-shaped combined steel dampers (UCSDs), via OpenSees. A high-speed train, running on the HSRBTS, is simulated through the moving spring mass column method (MSMCM). An innovative index, damage dispersion (), is proposed based on the seismic fragility analysis of two groups of components, categorized by their relative fragility in the HSRBTS, to probabilistically assess the impact of the dampers on seismic damage distribution among the system. The result shows that the UCSDs effectively disperse damage from more vulnerable components (fixed bearings, sliding layers, and CA mortar layers) to stronger ones (piers and fasteners). The observed decrease in the median and standard deviation of , identified as a logarithmic normal distribution, implies that UCSDs contribute to a more uniform damage distribution across the system, even when train effects are considered. The variation trend of with PGA shifts from an increase to a modest decline, and the values of exhibit a systematic reduction after considering train running, partially attributable to the train bogies in dissipating energy.","PeriodicalId":48642,"journal":{"name":"Structures","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-06DOI: 10.1016/j.istruc.2024.107220
Xuyue Wang, Sai Jia, Yuliang Wang, Zhongxian Liu
This study investigates the residual mechanical properties of a hybrid fibre-reinforced polymer (FRP)–ultra-high-performance concrete (UHPC)–steel double-skin tubular column (DSTC) subjected to lateral impact load. Lateral impact tests were conducted on six CFRP pipe–UHPC–steel tube composite hollow columns and one concrete steel tube hollow column. The residual mechanical properties and failure modes of the CFRP pipe–UHPC–steel tube composite hollow columns under lateral impact loads were analysed. The influence of different core concrete strength grades, CFRP winding layers, and inner steel tube diameters on the failure mode and residual bearing capacity of the steel tube composite hollow columns when the specimens were subjected to transverse impact loads was discussed. The ABAQUS finite element software was used to analyse the new composite columns. The simulation and test results were found to be consistent. The results showed that increasing the core concrete strength grade and inside diameter could improve the residual bearing capacity of steel tubes.
{"title":"Residual bearing capacity of hybrid fibre-reinforced polymer-ultra-high-performance concrete-steel double-skin tubular columns after impact loading","authors":"Xuyue Wang, Sai Jia, Yuliang Wang, Zhongxian Liu","doi":"10.1016/j.istruc.2024.107220","DOIUrl":"https://doi.org/10.1016/j.istruc.2024.107220","url":null,"abstract":"This study investigates the residual mechanical properties of a hybrid fibre-reinforced polymer (FRP)–ultra-high-performance concrete (UHPC)–steel double-skin tubular column (DSTC) subjected to lateral impact load. Lateral impact tests were conducted on six CFRP pipe–UHPC–steel tube composite hollow columns and one concrete steel tube hollow column. The residual mechanical properties and failure modes of the CFRP pipe–UHPC–steel tube composite hollow columns under lateral impact loads were analysed. The influence of different core concrete strength grades, CFRP winding layers, and inner steel tube diameters on the failure mode and residual bearing capacity of the steel tube composite hollow columns when the specimens were subjected to transverse impact loads was discussed. The ABAQUS finite element software was used to analyse the new composite columns. The simulation and test results were found to be consistent. The results showed that increasing the core concrete strength grade and inside diameter could improve the residual bearing capacity of steel tubes.","PeriodicalId":48642,"journal":{"name":"Structures","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-05DOI: 10.1016/j.istruc.2024.107144
Pengfei Tang, Yecheng Dai, Changheng Lu, Shaowei Hu
The structural performance of cold-formed steel (CFS) built-up sections under fire is significant in structural engineering. This study presents an efficient and reliable machine learning (ML) framework for predicting the axial capacity of CFS face-to-face (FTF) built-up channel sections at elevated temperatures. Using finite element (FE) datasets from the existing literature, the axial capacity of CFS-FTF built-up channel sections at elevated temperatures is predicted using different ML models, comprising Support Vector Machine, Radial Basis Neural Network, Artificial Neural Network, Extreme Learning Machine, Convolutional Neural Network and Boosting. Finally, the Boosting prediction was interpreted by the SHapley Additive exPlanations method to determine the significance of input features. The ML-based framework proposed in this study could offer a promising alternative for researchers and engineers to efficiently and effectively predict the axial capacity of CFS-FTF built-up channel sections at elevated temperatures.
在结构工程中，冷弯型钢（CFS）构建型钢在火灾下的结构性能非常重要。本研究提出了一种高效可靠的机器学习（ML）框架，用于预测 CFS 面对面（FTF）结构槽钢截面在高温下的轴向承载力。利用现有文献中的有限元（FE）数据集，采用不同的 ML 模型（包括支持向量机、径向基神经网络、人工神经网络、极限学习机、卷积神经网络和助推）预测 CFS-FTF 搭建槽段在高温下的轴向承载力。最后，通过 SHapley Additive exPlanations 方法对 Boosting 预测进行解释，以确定输入特征的重要性。本研究中提出的基于 ML 的框架可为研究人员和工程师提供一种有前途的替代方法，以高效、有效地预测 CFS-FTF 建筑渠道断面在高温下的轴向承载能力。
{"title":"A machine learning framework for predicting the axial capacity of cold-formed steel face-to-face built-up channel sections at elevated temperatures","authors":"Pengfei Tang, Yecheng Dai, Changheng Lu, Shaowei Hu","doi":"10.1016/j.istruc.2024.107144","DOIUrl":"https://doi.org/10.1016/j.istruc.2024.107144","url":null,"abstract":"The structural performance of cold-formed steel (CFS) built-up sections under fire is significant in structural engineering. This study presents an efficient and reliable machine learning (ML) framework for predicting the axial capacity of CFS face-to-face (FTF) built-up channel sections at elevated temperatures. Using finite element (FE) datasets from the existing literature, the axial capacity of CFS-FTF built-up channel sections at elevated temperatures is predicted using different ML models, comprising Support Vector Machine, Radial Basis Neural Network, Artificial Neural Network, Extreme Learning Machine, Convolutional Neural Network and Boosting. Finally, the Boosting prediction was interpreted by the SHapley Additive exPlanations method to determine the significance of input features. The ML-based framework proposed in this study could offer a promising alternative for researchers and engineers to efficiently and effectively predict the axial capacity of CFS-FTF built-up channel sections at elevated temperatures.","PeriodicalId":48642,"journal":{"name":"Structures","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-09-05DOI: 10.1016/j.istruc.2024.107193
Yirui Zhang, Yang Wei, Haopeng Jin, Jiyang Yi, Lin Liu, Sheng Li
Bridge pier columns are prone to steel corrosion and peeling of the concrete cover of the concrete in long-term service in the underwater environment. There is currently no better solution for improving the bearing capacity of bridge piers in underwater environments. To solve the problem, a novel reinforcement method was proposed for underwater bridge piers without cofferdams, which uses the stainless steel tube (SST) as an external template and fills the non-dispersed mortar (NDM) between the bridge piers and the SST. A total of 16 SST and NDM confined concrete tubular columns were prepared. Experiments were conducted to investigate the effect of confinement of the SST under axial load only on the core section to simulate the actual situation of underwater piers. The effects of the thickness of the SST and the types of NDM on the compressive performance of the core were compared. The test results indicate that the bearing capacity of the reinforced specimen can be increased by more than 2.5 times that of the original pier column. The thickness of the SST is the main parameter that affects the stress-strain curve. Compared to joint loading, core section loading can increase maximum stress by more than 10 %. A multiscale analysis was conducted on the model of steel tube confined concrete (STCC) columns. A method was proposed to calculate the bearing capacity of reinforced columns. The research results can provide a new method and theoretical basis for the reinforcement technology of underwater bridge piers.
{"title":"Behavior of underwater concrete columns confined by non-dispersive mortar and stainless steel tube subjected to core axial compression","authors":"Yirui Zhang, Yang Wei, Haopeng Jin, Jiyang Yi, Lin Liu, Sheng Li","doi":"10.1016/j.istruc.2024.107193","DOIUrl":"https://doi.org/10.1016/j.istruc.2024.107193","url":null,"abstract":"Bridge pier columns are prone to steel corrosion and peeling of the concrete cover of the concrete in long-term service in the underwater environment. There is currently no better solution for improving the bearing capacity of bridge piers in underwater environments. To solve the problem, a novel reinforcement method was proposed for underwater bridge piers without cofferdams, which uses the stainless steel tube (SST) as an external template and fills the non-dispersed mortar (NDM) between the bridge piers and the SST. A total of 16 SST and NDM confined concrete tubular columns were prepared. Experiments were conducted to investigate the effect of confinement of the SST under axial load only on the core section to simulate the actual situation of underwater piers. The effects of the thickness of the SST and the types of NDM on the compressive performance of the core were compared. The test results indicate that the bearing capacity of the reinforced specimen can be increased by more than 2.5 times that of the original pier column. The thickness of the SST is the main parameter that affects the stress-strain curve. Compared to joint loading, core section loading can increase maximum stress by more than 10 %. A multiscale analysis was conducted on the model of steel tube confined concrete (STCC) columns. A method was proposed to calculate the bearing capacity of reinforced columns. The research results can provide a new method and theoretical basis for the reinforcement technology of underwater bridge piers.","PeriodicalId":48642,"journal":{"name":"Structures","volume":null,"pages":null},"PeriodicalIF":4.1,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142222173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：