Yikang Li, Chenxi Li, Xiaomin Liu, Qian Zhang, Liu Yu
Summary Composite shear wall (CSW) system, which consists of a steel boundary frame and a steel panel with a reinforced concrete (RC) panel attached to one side of it using bolts, is commonly used in mid‐ to high‐rise buildings. In a CSW system, RC panel functions as out‐of‐plane restraint to prevent overall buckling of steel panel, thereby enhancing system behavior. However, for a traditional CSW system, the RC panel is in direct contact with the steel boundary frame. The RC panel tends to crush under seismic loading, thereby leading to a weak constraint to steel panel buckling. The innovative CSW system, where a gap remained between steel boundary frame and RC panel, demonstrated better cyclic behavior than the traditional CSW system. Current studies aimed to investigate cyclic behavior, parameter effects, and determination of RC panel stiffness of CSW systems. In this paper, detailed FE models were developed for simulating cyclic behavior of both innovative and traditional CSW systems and validated by test results. FE models accurately predicted lateral load‐drift response and failure patterns of both innovative and traditional CSW systems. System failure patterns and load‐carrying mechanism of RC panels were discussed. The effects of major parameters, including steel panel thickness, RC panel thickness, ratio of bolt spacing to steel panel thickness, and gap between frame and RC panel, were examined using the validated models. Simulation results indicated that steel panel thickness contributed to increase the lateral strength and initial stiffness of both innovative and traditional CSW systems. Although RC panel thickness, ratio of bolt spacing to steel panel thickness, and gap between frame and RC panel had negligible effects on system strength and stiffness, they should also be carefully designed to ensure local stability of the steel panel and system ductility. Formulations were proposed for predicting the lateral strength of both innovative and traditional CSW systems. The average difference between calculated and test/simulated lateral strength was less than 3%.
{"title":"Finite element simulation and strength evaluation on innovative and traditional composite shear wall systems","authors":"Yikang Li, Chenxi Li, Xiaomin Liu, Qian Zhang, Liu Yu","doi":"10.1002/tal.2060","DOIUrl":"https://doi.org/10.1002/tal.2060","url":null,"abstract":"Summary Composite shear wall (CSW) system, which consists of a steel boundary frame and a steel panel with a reinforced concrete (RC) panel attached to one side of it using bolts, is commonly used in mid‐ to high‐rise buildings. In a CSW system, RC panel functions as out‐of‐plane restraint to prevent overall buckling of steel panel, thereby enhancing system behavior. However, for a traditional CSW system, the RC panel is in direct contact with the steel boundary frame. The RC panel tends to crush under seismic loading, thereby leading to a weak constraint to steel panel buckling. The innovative CSW system, where a gap remained between steel boundary frame and RC panel, demonstrated better cyclic behavior than the traditional CSW system. Current studies aimed to investigate cyclic behavior, parameter effects, and determination of RC panel stiffness of CSW systems. In this paper, detailed FE models were developed for simulating cyclic behavior of both innovative and traditional CSW systems and validated by test results. FE models accurately predicted lateral load‐drift response and failure patterns of both innovative and traditional CSW systems. System failure patterns and load‐carrying mechanism of RC panels were discussed. The effects of major parameters, including steel panel thickness, RC panel thickness, ratio of bolt spacing to steel panel thickness, and gap between frame and RC panel, were examined using the validated models. Simulation results indicated that steel panel thickness contributed to increase the lateral strength and initial stiffness of both innovative and traditional CSW systems. Although RC panel thickness, ratio of bolt spacing to steel panel thickness, and gap between frame and RC panel had negligible effects on system strength and stiffness, they should also be carefully designed to ensure local stability of the steel panel and system ductility. Formulations were proposed for predicting the lateral strength of both innovative and traditional CSW systems. The average difference between calculated and test/simulated lateral strength was less than 3%.","PeriodicalId":49470,"journal":{"name":"Structural Design of Tall and Special Buildings","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135803209","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}
Summary Recycled steel wire is taken from used tires, and by procedures like mechanical cutting and friction treatment, it can be converted into industrial recycled steel fiber that meets precise criteria. Such green fiber may effectively limit the growth of fractures in concrete and diffuse the fracture energy of concrete when incorporated into concrete. An investigation of the effects of materials and horizontal reinforcement spacing on the seismic performance of shear wall specimens is presented in this research. The test and numerical simulation findings indicate that the RSFRC (recycled steel fiber reinforced concrete) shear wall's fracture is substantially narrower than that of a conventional shear wall and that the shear carrying capacity and deformation ductility of the shear wall have been greatly enhanced. The energy dissipation capacity of the RSFRC shear wall specimen with varying horizontal reinforcement spacing is significantly enhanced when compared to the conventional shear wall, and the ultimate displacements are reduced. RSFRC shear wall specimen has higher stiffness in the early stage, and the overall stiffness decreases slowly. With the decrease of fiber volume fraction of RSFRC shear wall in a certain range, the shear bearing capacity and stiffness of the model will decrease slightly, but the ductility will increase significantly. Compared with the RSFRC shear wall with fiber aspect ratio of 40 and 25, the bearing capacity and ductility of the two are close, but the RSFRC shear wall with low aspect ratio is slightly insufficient. When the axial compression ratio is in the range of 0.2–0.4, the horizontal shear capacity of RSFRC shear wall increases with the increase of vertical load, but the maximum horizontal displacement becomes smaller, and the model is damaged by compression. Using theoretical calculation, this work also creates the simplified calculation method and restoring force model for the bearing capacity of the diagonal section of RSFRC shear wall. The observed findings correspond well with the test hysteresis curve and may serve as a benchmark for future study. This study provides a new research direction for the seismic performance of RSFRC structures, as well as a solid theoretical foundation and promotion for future research.
{"title":"Study on seismic performance test and calculation method of recycled steel fiber reinforced concrete shear wall","authors":"Yan Li, Dong‐yi Li, Shan‐mu Zhao, Xiao‐peng Wang","doi":"10.1002/tal.2064","DOIUrl":"https://doi.org/10.1002/tal.2064","url":null,"abstract":"Summary Recycled steel wire is taken from used tires, and by procedures like mechanical cutting and friction treatment, it can be converted into industrial recycled steel fiber that meets precise criteria. Such green fiber may effectively limit the growth of fractures in concrete and diffuse the fracture energy of concrete when incorporated into concrete. An investigation of the effects of materials and horizontal reinforcement spacing on the seismic performance of shear wall specimens is presented in this research. The test and numerical simulation findings indicate that the RSFRC (recycled steel fiber reinforced concrete) shear wall's fracture is substantially narrower than that of a conventional shear wall and that the shear carrying capacity and deformation ductility of the shear wall have been greatly enhanced. The energy dissipation capacity of the RSFRC shear wall specimen with varying horizontal reinforcement spacing is significantly enhanced when compared to the conventional shear wall, and the ultimate displacements are reduced. RSFRC shear wall specimen has higher stiffness in the early stage, and the overall stiffness decreases slowly. With the decrease of fiber volume fraction of RSFRC shear wall in a certain range, the shear bearing capacity and stiffness of the model will decrease slightly, but the ductility will increase significantly. Compared with the RSFRC shear wall with fiber aspect ratio of 40 and 25, the bearing capacity and ductility of the two are close, but the RSFRC shear wall with low aspect ratio is slightly insufficient. When the axial compression ratio is in the range of 0.2–0.4, the horizontal shear capacity of RSFRC shear wall increases with the increase of vertical load, but the maximum horizontal displacement becomes smaller, and the model is damaged by compression. Using theoretical calculation, this work also creates the simplified calculation method and restoring force model for the bearing capacity of the diagonal section of RSFRC shear wall. The observed findings correspond well with the test hysteresis curve and may serve as a benchmark for future study. This study provides a new research direction for the seismic performance of RSFRC structures, as well as a solid theoretical foundation and promotion for future research.","PeriodicalId":49470,"journal":{"name":"Structural Design of Tall and Special Buildings","volume":"234 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135803538","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}
Summary The atmospheric boundary layer (ABL), whose total height is about 1–1.5 km, is composed of the atmospheric surface layer (ASL) and the Ekman layer, which typically account for the lower 10% and the upper 90% of the ABL, respectively. The wind veering angle in the Ekman layer can be between 10° and 30°, which may be an important influence factor for the wind‐resistant design of kilometer‐scale super‐tall buildings. Unfortunately, there is very little research on this issue so far due to the difficulty in simulations of veering wind in wind tunnels and computational fluid dynamics (CFD) simulation platforms. In this study, the simulations of non‐veering and veering wind fields are presented, and furthermore, the wind loads of kilometer‐scale super tall buildings with several typical configurations in veering wind fields are numerically investigated. Specifically, the large eddy simulations (LES) of unsteady flow around three buildings, namely, a square building, a tapered building (tapering ratio: 6.6%), and a 4‐layer setback building with the same height and the same aspect ratio of 9:1, are systematically performed for the cases of veering wind and non‐veering wind. The wind pressures and wind forces on these buildings are obtained and comprehensively analyzed. The differences in the wind loads among the building configurations are highlighted, and the mechanisms are discussed based on the time‐averaged and instantaneous flow fields.
{"title":"CFD simulation of wind loads of kilometer‐scale super tall buildings with typical configurations in veering wind field","authors":"Chengdong Feng, Ming Gu","doi":"10.1002/tal.2066","DOIUrl":"https://doi.org/10.1002/tal.2066","url":null,"abstract":"Summary The atmospheric boundary layer (ABL), whose total height is about 1–1.5 km, is composed of the atmospheric surface layer (ASL) and the Ekman layer, which typically account for the lower 10% and the upper 90% of the ABL, respectively. The wind veering angle in the Ekman layer can be between 10° and 30°, which may be an important influence factor for the wind‐resistant design of kilometer‐scale super‐tall buildings. Unfortunately, there is very little research on this issue so far due to the difficulty in simulations of veering wind in wind tunnels and computational fluid dynamics (CFD) simulation platforms. In this study, the simulations of non‐veering and veering wind fields are presented, and furthermore, the wind loads of kilometer‐scale super tall buildings with several typical configurations in veering wind fields are numerically investigated. Specifically, the large eddy simulations (LES) of unsteady flow around three buildings, namely, a square building, a tapered building (tapering ratio: 6.6%), and a 4‐layer setback building with the same height and the same aspect ratio of 9:1, are systematically performed for the cases of veering wind and non‐veering wind. The wind pressures and wind forces on these buildings are obtained and comprehensively analyzed. The differences in the wind loads among the building configurations are highlighted, and the mechanisms are discussed based on the time‐averaged and instantaneous flow fields.","PeriodicalId":49470,"journal":{"name":"Structural Design of Tall and Special Buildings","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135967925","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}
Yingliang Xu, Yan Liu, Fenglei Huang, Junbo Yan, Fan Bai, Xu Li, Hongfu Wang
Summary The objective of this study was to study the effect of load details of successive explosions on the blast behaviors of reinforced concrete (RC) beams. First, the effect of the successive loading of two identical explosions was discussed by considering the influences of standoff distance, charge mass on the failure states, and structural responses (displacement and support reaction force). And keeping the total TNT charge mass of 1 kg unchanged, the effect of loading numbers was investigated by loading two 0.5 kg TNT successively and a single 1 kg TNT on RC beams, respectively. Besides, the successive loading of two different explosions was also considered by investigating the effects of loading sequences and the first explosion induced pre‐damage on the ultimate accumulated damage of RC beams. At last, based on the reaction force and displacement responses, a nonlinear relationship between the dynamic residual load‐carrying capacity and the accumulated residual displacement was obtained to assess the damage states of the tested beams. The results show that the local failure range along the beam span direction (length of peeling‐off and length of spallation) caused by the first blast load did not apparently increase when the damaged beams were subjected to another blast load. With the increase in explosion numbers, depth of compressive crushing increases gradually. At the same stand‐off distance (from 0.25 to 0.45 m), due to the damage accumulation effect, successive loading of two 0.5 kg TNT can trigger more severe local failure but smaller accumulated residual deflection to beams than the single loading of a 1 kg TNT. Besides, when two different blast loads are loaded on tested beams, the loading sequence of the larger one first and then the smaller one (1 kg TNT/0.5 kg TNT at h = 0.45 m) can trigger larger damage to beams than the opposite loading sequence (0.5 kg TNT/1 kg TNT at h = 0.45 m). And for the beams subjected to a smaller blast load first and then a larger one, a stiffer behavior may be triggered by the second blast load on the beam after the first loading of the smaller blast load due to the residual strain in longitudinal reinforcement. Furthermore, based on the nonlinear relationship between residual load‐carrying capacity and residual displacement, the accumulated damage of RC beams was divided into mainly four phases.
摘要本研究的目的是研究连续爆炸荷载细部对钢筋混凝土梁爆炸性能的影响。首先，通过考虑距离、装药质量对破坏状态和结构响应(位移和支撑反力)的影响，讨论了两次相同爆炸连续加载的影响。在TNT总装药质量为1 kg不变的情况下，分别在RC梁上连续加载2个0.5 kg TNT和1个1 kg TNT，考察了加载次数的影响。此外，还考虑了两次不同爆炸的连续加载，研究了加载顺序和第一次爆炸引起的预损伤对RC梁最终累积损伤的影响。最后，基于反力和位移响应，建立了动残余承载力与累积残余位移之间的非线性关系，用于评价试验梁的损伤状态。结果表明:在第一次爆炸荷载作用下，沿梁跨方向的局部破坏范围(剥落长度和碎裂长度)在二次爆炸荷载作用下没有明显增大;随着爆炸次数的增加，压缩破碎深度逐渐增大。在相同的距离(从0.25到0.45米)，由于损伤累积效应，连续加载两个0.5 kg TNT可以触发更严重的局部破坏，但比单次加载1 kg TNT更小的累积残余挠度。另外，在试验梁上加载两种不同爆炸荷载时，先大后小的加载顺序(1 kg TNT/0.5 kg TNT, h = 0.45 m)比相反的加载顺序(0.5 kg TNT/1 kg TNT, h = 0.45 m)对梁的损伤更大。由于纵向钢筋的残余应变，在较小的爆炸荷载的第一次加载之后，梁上的第二次爆炸荷载可能会触发更刚性的行为。基于残余承载力与残余位移之间的非线性关系，将钢筋混凝土梁的累积损伤主要分为四个阶段。
{"title":"Effect of load details of the successive explosions on the blast behaviors of reinforced concrete beams","authors":"Yingliang Xu, Yan Liu, Fenglei Huang, Junbo Yan, Fan Bai, Xu Li, Hongfu Wang","doi":"10.1002/tal.2061","DOIUrl":"https://doi.org/10.1002/tal.2061","url":null,"abstract":"Summary The objective of this study was to study the effect of load details of successive explosions on the blast behaviors of reinforced concrete (RC) beams. First, the effect of the successive loading of two identical explosions was discussed by considering the influences of standoff distance, charge mass on the failure states, and structural responses (displacement and support reaction force). And keeping the total TNT charge mass of 1 kg unchanged, the effect of loading numbers was investigated by loading two 0.5 kg TNT successively and a single 1 kg TNT on RC beams, respectively. Besides, the successive loading of two different explosions was also considered by investigating the effects of loading sequences and the first explosion induced pre‐damage on the ultimate accumulated damage of RC beams. At last, based on the reaction force and displacement responses, a nonlinear relationship between the dynamic residual load‐carrying capacity and the accumulated residual displacement was obtained to assess the damage states of the tested beams. The results show that the local failure range along the beam span direction (length of peeling‐off and length of spallation) caused by the first blast load did not apparently increase when the damaged beams were subjected to another blast load. With the increase in explosion numbers, depth of compressive crushing increases gradually. At the same stand‐off distance (from 0.25 to 0.45 m), due to the damage accumulation effect, successive loading of two 0.5 kg TNT can trigger more severe local failure but smaller accumulated residual deflection to beams than the single loading of a 1 kg TNT. Besides, when two different blast loads are loaded on tested beams, the loading sequence of the larger one first and then the smaller one (1 kg TNT/0.5 kg TNT at h = 0.45 m) can trigger larger damage to beams than the opposite loading sequence (0.5 kg TNT/1 kg TNT at h = 0.45 m). And for the beams subjected to a smaller blast load first and then a larger one, a stiffer behavior may be triggered by the second blast load on the beam after the first loading of the smaller blast load due to the residual strain in longitudinal reinforcement. Furthermore, based on the nonlinear relationship between residual load‐carrying capacity and residual displacement, the accumulated damage of RC beams was divided into mainly four phases.","PeriodicalId":49470,"journal":{"name":"Structural Design of Tall and Special Buildings","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136212994","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}
Summary Although the concentrically braced frames (CBFs) systems have high lateral elastic stiffness and strength, they reflect a low seismic energy absorption capacity mainly due to their diagonal buckling under compressive loading. To overcome this problem, researchers have proposed metallic shear damper as the most popular due to its satisfactory performance and affordable cost. In this paper, an innovative metallic damper with a flexural mechanism is proposed to improve the behavior of CBF systems. It provides ease of fabrication and replacement after damage, competitive cost, and improved resistance to buckling of the CBF member. The performance of the damper was evaluated experimentally and numerically. Subsequently, two types of dampers, (a) made of rectangular flexural plates (RFP) and (b) made of I‐shaped flexural plates (IFP), were designed and evaluated. Experimental as well as numerical results indicated that both dampers provide stable and symmetrical hysteresis curves with a high energy absorption capacity. Results indicated that the IFP damper has greater stiffness (1.94–2.3 times) and ultimate strength (1.76 times) but a lower overstrength (66% less) and ductility (47% less) than the RFP damper. Moreover, design expressions were presented for the proposed damper and showed a good agreement with finite element results.
{"title":"Improving the behavior of concentrically braced frame braces using a flexural damper: Experimental and numerical study","authors":"Seong‐Hoon Jeong, Ali Ghamari, Akram Jawdhari","doi":"10.1002/tal.2059","DOIUrl":"https://doi.org/10.1002/tal.2059","url":null,"abstract":"Summary Although the concentrically braced frames (CBFs) systems have high lateral elastic stiffness and strength, they reflect a low seismic energy absorption capacity mainly due to their diagonal buckling under compressive loading. To overcome this problem, researchers have proposed metallic shear damper as the most popular due to its satisfactory performance and affordable cost. In this paper, an innovative metallic damper with a flexural mechanism is proposed to improve the behavior of CBF systems. It provides ease of fabrication and replacement after damage, competitive cost, and improved resistance to buckling of the CBF member. The performance of the damper was evaluated experimentally and numerically. Subsequently, two types of dampers, (a) made of rectangular flexural plates (RFP) and (b) made of I‐shaped flexural plates (IFP), were designed and evaluated. Experimental as well as numerical results indicated that both dampers provide stable and symmetrical hysteresis curves with a high energy absorption capacity. Results indicated that the IFP damper has greater stiffness (1.94–2.3 times) and ultimate strength (1.76 times) but a lower overstrength (66% less) and ductility (47% less) than the RFP damper. Moreover, design expressions were presented for the proposed damper and showed a good agreement with finite element results.","PeriodicalId":49470,"journal":{"name":"Structural Design of Tall and Special Buildings","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136213610","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}
John Hickey, Hollie Moore, Brian Broderick, Breiffni Fitzgerald
Abstract The damping ratio is a key indicator of an individual structure's susceptibility to dynamic loads, including the level of discomfort experienced by the occupants of a tall building subjected to wind loading. While computational models, laboratory studies and empirical data can provide estimates of structural damping, the most reliable way to evaluate true damping ratio values is through modal identification using data from field tests on full‐scale finished structures. As an innovative form of construction, high‐rise modular buildings have not been the subject of previous vibration monitoring investigations, implying an absence of essential structural dynamics information. This paper assesses the reliability of four modal identification methods for estimating the damping ratio of a structure using ambient acceleration response data recorded from the world's tallest modular structure, the Ten Degrees building in Croydon, South London. The methods considered are two implementations of the Bayesian fast Fourier transform (BFFT), the random decrement technique (RDT), and a hybrid of the RDT which first decomposes the ambient data into sub‐signals using analytical mode decomposition (AMD‐RDT). Each method is applied to response data collected during 10 significant wind loading events to evaluate the inherent modal properties of the structure, with the computed damping ratio values compared between methods and events. By reporting the first measured damping ratios for a tall modular structure, the paper makes an important contribution to knowledge about the vibration properties of an emerging form of construction.
{"title":"Structural damping estimation from live monitoring of a tall modular building","authors":"John Hickey, Hollie Moore, Brian Broderick, Breiffni Fitzgerald","doi":"10.1002/tal.2067","DOIUrl":"https://doi.org/10.1002/tal.2067","url":null,"abstract":"Abstract The damping ratio is a key indicator of an individual structure's susceptibility to dynamic loads, including the level of discomfort experienced by the occupants of a tall building subjected to wind loading. While computational models, laboratory studies and empirical data can provide estimates of structural damping, the most reliable way to evaluate true damping ratio values is through modal identification using data from field tests on full‐scale finished structures. As an innovative form of construction, high‐rise modular buildings have not been the subject of previous vibration monitoring investigations, implying an absence of essential structural dynamics information. This paper assesses the reliability of four modal identification methods for estimating the damping ratio of a structure using ambient acceleration response data recorded from the world's tallest modular structure, the Ten Degrees building in Croydon, South London. The methods considered are two implementations of the Bayesian fast Fourier transform (BFFT), the random decrement technique (RDT), and a hybrid of the RDT which first decomposes the ambient data into sub‐signals using analytical mode decomposition (AMD‐RDT). Each method is applied to response data collected during 10 significant wind loading events to evaluate the inherent modal properties of the structure, with the computed damping ratio values compared between methods and events. By reporting the first measured damping ratios for a tall modular structure, the paper makes an important contribution to knowledge about the vibration properties of an emerging form of construction.","PeriodicalId":49470,"journal":{"name":"Structural Design of Tall and Special Buildings","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136358965","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}
Summary This study investigates the flexural performance and degree of composite action (DCA) of precast concrete sandwich panels (PCSPs) with four types of connectors. Five full‐scale specimens were designed, and 4‐point bending tests were performed. The specimens included four PCSPs utilizing glass fiber reinforced polymer (GFRP) truss connectors, steel truss connectors, concrete rib connectors, and GFRP pin connectors, respectively, along with a solid panel (SP). The results indicated that the flexural performance and DCA provided by the four types of connectors followed an ascending order as follows: GFRP pin‐type connectors, GFRP truss connectors, steel truss connectors, and concrete rib‐type connectors. Moreover, the study presented a novel method for calculating DCA, namely, the neutral axis method, which was compared with the displacement and strain methods. The reasonableness and accuracy of the neutral axis method in calculating DCA during the linear elastic stage were verified. Results indicated that the neutral axis method provided more precise and reasonable DCA that closely matched the experimental results compared with the displacement and strain methods. Additionally, the neutral axis method was simpler to calculate DCA and had a broader range of applications. Finally, the study provided recommendations for the optimal application scenarios of each calculation method.
{"title":"Study of the flexural performance and a novel calculation formula for the degree of composite action for precast concrete sandwich panels","authors":"Tiancai Zheng, Qi Ge, Feng Xiong, Guo Li, Yu Xue, Xiang Deng","doi":"10.1002/tal.2065","DOIUrl":"https://doi.org/10.1002/tal.2065","url":null,"abstract":"Summary This study investigates the flexural performance and degree of composite action (DCA) of precast concrete sandwich panels (PCSPs) with four types of connectors. Five full‐scale specimens were designed, and 4‐point bending tests were performed. The specimens included four PCSPs utilizing glass fiber reinforced polymer (GFRP) truss connectors, steel truss connectors, concrete rib connectors, and GFRP pin connectors, respectively, along with a solid panel (SP). The results indicated that the flexural performance and DCA provided by the four types of connectors followed an ascending order as follows: GFRP pin‐type connectors, GFRP truss connectors, steel truss connectors, and concrete rib‐type connectors. Moreover, the study presented a novel method for calculating DCA, namely, the neutral axis method, which was compared with the displacement and strain methods. The reasonableness and accuracy of the neutral axis method in calculating DCA during the linear elastic stage were verified. Results indicated that the neutral axis method provided more precise and reasonable DCA that closely matched the experimental results compared with the displacement and strain methods. Additionally, the neutral axis method was simpler to calculate DCA and had a broader range of applications. Finally, the study provided recommendations for the optimal application scenarios of each calculation method.","PeriodicalId":49470,"journal":{"name":"Structural Design of Tall and Special Buildings","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136359098","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}
Mohammadjavad Hamidia, Sara Jamshidian, Mobinasadat Afzali, Mohammad Safi
Summary This paper presents a novel method for estimating the seismic peak interstory drift ratio (IDR) in reinforced concrete (RC) columns after an earthquake using surface crack image analysis. The quantitative representation of the complexity and irregularity of crack images in damaged RC columns is obtained through the consideration of the generalized fractal dimensions. The authors have compiled a comprehensive database consisting of 445 crack maps obtained from cyclic experiments conducted on 110 rectangular RC column specimens exhibiting double‐curvature deformation mode. This database is utilized by the authors to develop and validate the proposed procedure. The research database contains a wide range of structural and geometric features. Five closed‐form equations are developed with the objective of estimating the peak IDR experienced by the RC columns during a seismic event. The predictive equations are derived through the utilization of symbolic regression technique, with the input parameters varying according to the availability of columns characteristic parameters. Results reveal that generalized fractal dimensions, especially D −1 , are strong vision‐based indicator of damage in RC columns having correlation coefficients with IDR ranging from 0.82 to 0.92 across the considered plans. The seismic peak IDR obtained through the empirical equations can serve as the input engineering demand parameter (EDP) in the seismic loss estimation frameworks. This allows for the determination of the probability of exceeding damage states for structural and nonstructural components of concrete buildings. Finally, the practical implementation of the methodology is examined by its application to an actual case of a damaged column during the Kermanshah earthquake of magnitude 7.3 that occurred in 2017.
{"title":"Machine vision‐based automated earthquake‐induced drift ratio quantification for reinforced concrete columns","authors":"Mohammadjavad Hamidia, Sara Jamshidian, Mobinasadat Afzali, Mohammad Safi","doi":"10.1002/tal.2062","DOIUrl":"https://doi.org/10.1002/tal.2062","url":null,"abstract":"Summary This paper presents a novel method for estimating the seismic peak interstory drift ratio (IDR) in reinforced concrete (RC) columns after an earthquake using surface crack image analysis. The quantitative representation of the complexity and irregularity of crack images in damaged RC columns is obtained through the consideration of the generalized fractal dimensions. The authors have compiled a comprehensive database consisting of 445 crack maps obtained from cyclic experiments conducted on 110 rectangular RC column specimens exhibiting double‐curvature deformation mode. This database is utilized by the authors to develop and validate the proposed procedure. The research database contains a wide range of structural and geometric features. Five closed‐form equations are developed with the objective of estimating the peak IDR experienced by the RC columns during a seismic event. The predictive equations are derived through the utilization of symbolic regression technique, with the input parameters varying according to the availability of columns characteristic parameters. Results reveal that generalized fractal dimensions, especially D −1 , are strong vision‐based indicator of damage in RC columns having correlation coefficients with IDR ranging from 0.82 to 0.92 across the considered plans. The seismic peak IDR obtained through the empirical equations can serve as the input engineering demand parameter (EDP) in the seismic loss estimation frameworks. This allows for the determination of the probability of exceeding damage states for structural and nonstructural components of concrete buildings. Finally, the practical implementation of the methodology is examined by its application to an actual case of a damaged column during the Kermanshah earthquake of magnitude 7.3 that occurred in 2017.","PeriodicalId":49470,"journal":{"name":"Structural Design of Tall and Special Buildings","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135254124","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}
Summary Tuned liquid dampers provide structure control with the help of the liquid mass in tanks that are attached to the structure. The mass ratio affects the optimum tuned liquid damper (TLD) parameters. This study examines the effect of mass ratio on the control performance of TLD devices in providing seismic control of structures with different damping ratios. For this purpose, TLD devices with different mass ratios were placed on two different single‐story steel and reinforced concrete structure models, and their performance under earthquake excitation was investigated. TLD parameters for obtaining the optimum displacement level in the 0.5‐ and 1.0‐s structure natural period for both structure types were optimized with the Jaya algorithm (JA), which is a metaheuristic algorithm. By using the optimum TLD parameters, the structural displacement and total acceleration values were obtained by the critical earthquake analysis. When the results are examined, it is understood that TLD mass increase from a 20% mass ratio for both structure types and selected structure periods does not have a significant effect on TLD control performance.
{"title":"Mass ratio factor in control performance of optimum tuned liquid dampers","authors":"Ayla Ocak, Gebrail Bekdaş, Sinan Melih Nigdeli","doi":"10.1002/tal.2063","DOIUrl":"https://doi.org/10.1002/tal.2063","url":null,"abstract":"Summary Tuned liquid dampers provide structure control with the help of the liquid mass in tanks that are attached to the structure. The mass ratio affects the optimum tuned liquid damper (TLD) parameters. This study examines the effect of mass ratio on the control performance of TLD devices in providing seismic control of structures with different damping ratios. For this purpose, TLD devices with different mass ratios were placed on two different single‐story steel and reinforced concrete structure models, and their performance under earthquake excitation was investigated. TLD parameters for obtaining the optimum displacement level in the 0.5‐ and 1.0‐s structure natural period for both structure types were optimized with the Jaya algorithm (JA), which is a metaheuristic algorithm. By using the optimum TLD parameters, the structural displacement and total acceleration values were obtained by the critical earthquake analysis. When the results are examined, it is understood that TLD mass increase from a 20% mass ratio for both structure types and selected structure periods does not have a significant effect on TLD control performance.","PeriodicalId":49470,"journal":{"name":"Structural Design of Tall and Special Buildings","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135482193","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}
Bo Li, Zhen Han, Xinxin Zhang, Qingshan Yang, Chen Li, Lin Sun
Summary Atmospheric flow is the main factor affecting the wind load of urban buildings. The measured data observed continuously from the 325‐m‐tall Beijing Meteorological Tower (BMT) during 2013–2017 is employed to investigate the vertically‐layered structure and surface roughness parameters of the urban boundary layer. Based on the local similarity theory and analysis results of the atmospheric stability and local friction velocity, it can be determined that the height of 80 m is near the bottom of the inertial sub‐layer, the range below this height belongs to the roughness sub‐layer, 140 m belongs to the inertial sub‐layer, and 200 m and 280 m are in the mixing layer. The local friction velocity at 80 m can be considered a relatively reliable value as the friction velocity. Moreover, seasonal effect on local friction velocity is minimal. According to the fitting result of near‐neutral strong wind samples by the log‐law, it is concluded that to obtain a more accurate wind speed profile, all layers should be included when picking fitting heights. In addition, surface roughness parameters are affected by the wind direction and speed. The variation according to the wind direction corresponds to the topographical distribution surrounding the BMT, and the higher range of wind speed may be more applicable for estimating surface roughness parameters.
{"title":"Investigation of the vertically‐layered structure and surface roughness parameters of the urban boundary layer","authors":"Bo Li, Zhen Han, Xinxin Zhang, Qingshan Yang, Chen Li, Lin Sun","doi":"10.1002/tal.2056","DOIUrl":"https://doi.org/10.1002/tal.2056","url":null,"abstract":"Summary Atmospheric flow is the main factor affecting the wind load of urban buildings. The measured data observed continuously from the 325‐m‐tall Beijing Meteorological Tower (BMT) during 2013–2017 is employed to investigate the vertically‐layered structure and surface roughness parameters of the urban boundary layer. Based on the local similarity theory and analysis results of the atmospheric stability and local friction velocity, it can be determined that the height of 80 m is near the bottom of the inertial sub‐layer, the range below this height belongs to the roughness sub‐layer, 140 m belongs to the inertial sub‐layer, and 200 m and 280 m are in the mixing layer. The local friction velocity at 80 m can be considered a relatively reliable value as the friction velocity. Moreover, seasonal effect on local friction velocity is minimal. According to the fitting result of near‐neutral strong wind samples by the log‐law, it is concluded that to obtain a more accurate wind speed profile, all layers should be included when picking fitting heights. In addition, surface roughness parameters are affected by the wind direction and speed. The variation according to the wind direction corresponds to the topographical distribution surrounding the BMT, and the higher range of wind speed may be more applicable for estimating surface roughness parameters.","PeriodicalId":49470,"journal":{"name":"Structural Design of Tall and Special Buildings","volume":"122 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135206882","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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