The seismic performance and construction speed of the prefabricated steel structures are greatly influenced by the configuration of the beam–column joints. The stepped beam–column joint proposed in this paper, featuring with flush surfaces on both the upper and lower beam flanges, was designed to satisfy the requirements of favorable seismic resistance and high installation efficiency. Notably, the junction between the stepped cantilever segment and the stepped beam segment is crucial in the stepped joint. Therefore, cyclic loading tests were conducted on two cantilever specimens with different connection forms to determine their seismic behavior and failure modes. The experimental results indicated that the connection forms have a minor effect on the elastic phase behavior. However, a significant influence was observed on the ultimate load‐bearing capacity and energy dissipation. The result also indicated that the specimen with a thicker end plate exhibited excellent seismic performance, with favorable load‐bearing and plastic deformation capacity. The seismic performance of the joint specimen with U‐shaped latch was inferior, with the welding seam on the flange connected to the end plate tearing prematurely due to the stress concentration. Besides, elaborate finite element models were established, which were confirmed by the test results. Finally, parametric analysis considering the effect of end plate thickness was conducted, and the bolts' forces during the loading progress on the connection surfaces were analyzed. The result indicated that the joint's load‐bearing capacity and stiffness would decrease with the reduction of end plate thickness.
预制钢结构的抗震性能和施工速度在很大程度上受到梁柱连接构造的影响。本文提出的阶梯式梁柱连接结构，上下梁翼缘表面平齐，可满足良好的抗震性能和较高的安装效率要求。值得注意的是，在阶梯式连接中，阶梯式悬臂段和阶梯式梁段之间的交界处至关重要。因此，对采用不同连接形式的两个悬臂试件进行了循环加载试验，以确定其抗震行为和破坏模式。实验结果表明，连接形式对弹性阶段的行为影响较小。但对极限承载能力和能量耗散的影响很大。结果还表明，端板较厚的试样具有良好的抗震性能，承载能力和塑性变形能力都很强。而带有 U 型插销的连接试件抗震性能较差，与端板连接的凸缘焊缝因应力集中而过早撕裂。此外，还建立了精细的有限元模型，并得到了试验结果的证实。最后，进行了考虑端板厚度影响的参数分析，并分析了加载过程中螺栓在连接面上的作用力。结果表明，接头的承载能力和刚度会随着端板厚度的减小而降低。
{"title":"Seismic performance of the cantilever segment in prefabricated stepped beam–column joints","authors":"Yun Li, Yi An, Xin Cheng, Wenda Li, Yuehan Jin","doi":"10.1002/tal.2170","DOIUrl":"https://doi.org/10.1002/tal.2170","url":null,"abstract":"The seismic performance and construction speed of the prefabricated steel structures are greatly influenced by the configuration of the beam–column joints. The stepped beam–column joint proposed in this paper, featuring with flush surfaces on both the upper and lower beam flanges, was designed to satisfy the requirements of favorable seismic resistance and high installation efficiency. Notably, the junction between the stepped cantilever segment and the stepped beam segment is crucial in the stepped joint. Therefore, cyclic loading tests were conducted on two cantilever specimens with different connection forms to determine their seismic behavior and failure modes. The experimental results indicated that the connection forms have a minor effect on the elastic phase behavior. However, a significant influence was observed on the ultimate load‐bearing capacity and energy dissipation. The result also indicated that the specimen with a thicker end plate exhibited excellent seismic performance, with favorable load‐bearing and plastic deformation capacity. The seismic performance of the joint specimen with U‐shaped latch was inferior, with the welding seam on the flange connected to the end plate tearing prematurely due to the stress concentration. Besides, elaborate finite element models were established, which were confirmed by the test results. Finally, parametric analysis considering the effect of end plate thickness was conducted, and the bolts' forces during the loading progress on the connection surfaces were analyzed. The result indicated that the joint's load‐bearing capacity and stiffness would decrease with the reduction of end plate thickness.","PeriodicalId":501238,"journal":{"name":"The Structural Design of Tall and Special Buildings","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142188853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jaber Koopaizadeh, F. Behnamfar, Mohammad Reza Haghighi Tafti
This study seeks to integrate steel shear walls with precast concrete systems into stable and resistant structures against lateral loads. It is desired to study the ductility factor, lateral strength, and behavior as well as the energy absorption of this integrated system compared to the precast concrete frame without a shear wall. For this purpose, two steel shear wall samples made of mild steel and galvanized steel plates are constructed within a precast concrete frame. The assembly is tested under a cyclic lateral load. The integrity of the connections of steel strips of the wall together, and the boundary of the wall to the frame, is observed to be excellent. The main failure mode is composed of the diagonal yielding of the steel wall. The system benefits from large hysteresis loops and no degradation because of any instability. The beam‐column connections remain almost intact even at large cycles of deformation. Moreover, a bare precast concrete frame is tested in the same way to compare the lateral behavior. The utilized ductile beam‐column connections are successful in retaining the integrity of the system until large drifts. However, the seismic design characteristics of the bare frame turn out to be inferior to the steel shear wall system. Results of the cyclic tests show that by proper design of the interior and exterior connections of the shear wall as well as the beam‐column connections, the steel shear wall system can largely increase the stiffness, ultimate strength, and energy dissipation capacity of a bare precast moment resisting reinforced concrete frame. On top of that, the system is able to retain its integrity up to lateral drifts over 2%.
{"title":"Experimental evaluation of cyclic behavior of precast concrete frame with steel shear wall","authors":"Jaber Koopaizadeh, F. Behnamfar, Mohammad Reza Haghighi Tafti","doi":"10.1002/tal.2164","DOIUrl":"https://doi.org/10.1002/tal.2164","url":null,"abstract":"This study seeks to integrate steel shear walls with precast concrete systems into stable and resistant structures against lateral loads. It is desired to study the ductility factor, lateral strength, and behavior as well as the energy absorption of this integrated system compared to the precast concrete frame without a shear wall. For this purpose, two steel shear wall samples made of mild steel and galvanized steel plates are constructed within a precast concrete frame. The assembly is tested under a cyclic lateral load. The integrity of the connections of steel strips of the wall together, and the boundary of the wall to the frame, is observed to be excellent. The main failure mode is composed of the diagonal yielding of the steel wall. The system benefits from large hysteresis loops and no degradation because of any instability. The beam‐column connections remain almost intact even at large cycles of deformation. Moreover, a bare precast concrete frame is tested in the same way to compare the lateral behavior. The utilized ductile beam‐column connections are successful in retaining the integrity of the system until large drifts. However, the seismic design characteristics of the bare frame turn out to be inferior to the steel shear wall system. Results of the cyclic tests show that by proper design of the interior and exterior connections of the shear wall as well as the beam‐column connections, the steel shear wall system can largely increase the stiffness, ultimate strength, and energy dissipation capacity of a bare precast moment resisting reinforced concrete frame. On top of that, the system is able to retain its integrity up to lateral drifts over 2%.","PeriodicalId":501238,"journal":{"name":"The Structural Design of Tall and Special Buildings","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141927115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Computational fluid dynamic (CFD) has not been widely accepted as a design tool in current wind‐resistant structural design practices due to its contentious accuracy. To promote the application of CFD in wind‐resistant structural design, the accuracy of CFD should be comprehensively validated. However, most previous validation studies were focused on isolated generic or regular‐shaped buildings. This paper evaluates the accuracy of large eddy simulation (LES) in predicting the wind loads on a 600‐m‐high supertall building with a complex appearance in a realistic urban area against wind tunnel test results. The aerodynamic characteristics obtained from the LES and the wind tunnel test are compared and analyzed in detail, including wind pressure and force coefficients, wind force spectra, base moments, and correlations of the wind loads. This study aims to assess the performance and potential as well as the strengths and weaknesses of CFD in predicting wind loads on high‐rise buildings in an urban environment and promote its application to the wind‐resistant design of skyscrapers.
{"title":"Assessment of computational fluid dynamic as a design tool for estimation of wind loads on unconventional skyscrapers in urban environment","authors":"Bin Lu, Qiu‐Sheng Li, Xu‐Liang Han","doi":"10.1002/tal.2165","DOIUrl":"https://doi.org/10.1002/tal.2165","url":null,"abstract":"Computational fluid dynamic (CFD) has not been widely accepted as a design tool in current wind‐resistant structural design practices due to its contentious accuracy. To promote the application of CFD in wind‐resistant structural design, the accuracy of CFD should be comprehensively validated. However, most previous validation studies were focused on isolated generic or regular‐shaped buildings. This paper evaluates the accuracy of large eddy simulation (LES) in predicting the wind loads on a 600‐m‐high supertall building with a complex appearance in a realistic urban area against wind tunnel test results. The aerodynamic characteristics obtained from the LES and the wind tunnel test are compared and analyzed in detail, including wind pressure and force coefficients, wind force spectra, base moments, and correlations of the wind loads. This study aims to assess the performance and potential as well as the strengths and weaknesses of CFD in predicting wind loads on high‐rise buildings in an urban environment and promote its application to the wind‐resistant design of skyscrapers.","PeriodicalId":501238,"journal":{"name":"The Structural Design of Tall and Special Buildings","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141741480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Anbarasu, Mohammad Adil Dar, Gopal Mohan Ganesh, M. Kathiresan
In recent years, there has been a compelling need to adopt cold‐formed ultra‐high‐strength steel (CFUSS) in the construction industry owing to its numerous advantages, such as a higher strength‐to‐weight ratio, flexibility in achieving desired shapes, and adaptability over longer spans. Among the various applications, CFUSS lipped channel sections are commonly used as purlins and joists in steel structural systems. However, these sections are susceptible to different failure modes, particularly web crippling, which presents significant challenges. Currently, the current design rules lack specific guidelines for estimating the web crippling capacity of CFUSS sections. To address this crucial gap, the present study focuses on a comprehensive numerical investigation of the web crippling response of CFUSS lipped channel sections under interior‐two‐flange (ITF) loading conditions. Finite element (FE) models were developed using the ABAQUS package, verified against published test data, and subsequently used in an extensive parametric study. The ultimate web crippling capacity obtained from the parametric study was used to evaluate the accuracy of the current design equations in various design standards. The findings revealed that the existing design equations inadequately predicted the ultimate web crippling capacity of CFUSS lipped channel sections subjected to the ITF loading condition. Consequently, a modified design equation is proposed, utilizing the same approach as the current design standards, and a new direct strength method (DSM) approach is developed and verified through reliability analysis. The proposed modified design equations offer promising solutions to ensure safer and more reliable design practices for CFUSS structures in the construction industry.
{"title":"Web crippling design of cold‐formed ultra‐high strength steel lipped channels under ITF loading: A numerical parametric investigation","authors":"M. Anbarasu, Mohammad Adil Dar, Gopal Mohan Ganesh, M. Kathiresan","doi":"10.1002/tal.2166","DOIUrl":"https://doi.org/10.1002/tal.2166","url":null,"abstract":"In recent years, there has been a compelling need to adopt cold‐formed ultra‐high‐strength steel (CFUSS) in the construction industry owing to its numerous advantages, such as a higher strength‐to‐weight ratio, flexibility in achieving desired shapes, and adaptability over longer spans. Among the various applications, CFUSS lipped channel sections are commonly used as purlins and joists in steel structural systems. However, these sections are susceptible to different failure modes, particularly web crippling, which presents significant challenges. Currently, the current design rules lack specific guidelines for estimating the web crippling capacity of CFUSS sections. To address this crucial gap, the present study focuses on a comprehensive numerical investigation of the web crippling response of CFUSS lipped channel sections under interior‐two‐flange (ITF) loading conditions. Finite element (FE) models were developed using the ABAQUS package, verified against published test data, and subsequently used in an extensive parametric study. The ultimate web crippling capacity obtained from the parametric study was used to evaluate the accuracy of the current design equations in various design standards. The findings revealed that the existing design equations inadequately predicted the ultimate web crippling capacity of CFUSS lipped channel sections subjected to the ITF loading condition. Consequently, a modified design equation is proposed, utilizing the same approach as the current design standards, and a new direct strength method (DSM) approach is developed and verified through reliability analysis. The proposed modified design equations offer promising solutions to ensure safer and more reliable design practices for CFUSS structures in the construction industry.","PeriodicalId":501238,"journal":{"name":"The Structural Design of Tall and Special Buildings","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141647733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Iálysson da Silva Medeiros, Maria Isabela Marques da Cunha Vieira Bello, Douglas Mateus de Lima
The ongoing advancement of wind turbines, aiming for taller towers to harness more intense winds, poses substantial structural challenges. Soil‐structure interaction (SSI) assumes fundamental importance, necessitating precise analysis, and mathematical modeling. This study focuses on examining how SSI influences horizontal‐axis wind turbine tower‐foundation systems. Six numerical models, varying from simplified to more complex representations, are created using the finite element method (FEM) in ANSYS software. The analysis reveals significant sensitivity to support conditions, particularly elastic supports, causing the greatest displacement at the tower's top (1.899 m), highlighting the substantial influence of SSI and second‐order effects. Incorporating SSI and second‐order effects results in a 30.11% increase in von Mises stress at the base flange (73.4 MPa), compared to models excluding these factors. Stress variation along the tower height notably increases with second‐order effects; however, the structure maintains a 13.32% safety margin relative to steel load‐bearing capacity. Foundation analyses indicate stresses exceeding concrete's allowable stress by 24.3%, underscoring the need for foundation optimization. These results stress the importance of considering SSI and geometric nonlinearity for wind turbine development. The lack of comparable studies in literature underscores the significance of this research in advancing the field's knowledge.
{"title":"Influence of soil‐structure interaction on the behavior of the tower‐foundation system of a horizontal‐axis wind turbine","authors":"Iálysson da Silva Medeiros, Maria Isabela Marques da Cunha Vieira Bello, Douglas Mateus de Lima","doi":"10.1002/tal.2163","DOIUrl":"https://doi.org/10.1002/tal.2163","url":null,"abstract":"The ongoing advancement of wind turbines, aiming for taller towers to harness more intense winds, poses substantial structural challenges. Soil‐structure interaction (SSI) assumes fundamental importance, necessitating precise analysis, and mathematical modeling. This study focuses on examining how SSI influences horizontal‐axis wind turbine tower‐foundation systems. Six numerical models, varying from simplified to more complex representations, are created using the finite element method (FEM) in ANSYS software. The analysis reveals significant sensitivity to support conditions, particularly elastic supports, causing the greatest displacement at the tower's top (1.899 m), highlighting the substantial influence of SSI and second‐order effects. Incorporating SSI and second‐order effects results in a 30.11% increase in von Mises stress at the base flange (73.4 MPa), compared to models excluding these factors. Stress variation along the tower height notably increases with second‐order effects; however, the structure maintains a 13.32% safety margin relative to steel load‐bearing capacity. Foundation analyses indicate stresses exceeding concrete's allowable stress by 24.3%, underscoring the need for foundation optimization. These results stress the importance of considering SSI and geometric nonlinearity for wind turbine development. The lack of comparable studies in literature underscores the significance of this research in advancing the field's knowledge.","PeriodicalId":501238,"journal":{"name":"The Structural Design of Tall and Special Buildings","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141612928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study extended the electromechanical impedance (EMI) technique to monitor the 28‐day age of strength gain in mass concrete, although it has been validated in strength monitoring of a lab‐scaled concrete specimen. Embedded piezoelectric (PZT) transducer, namely, aluminum embedded PZT (AEP), that was wrapped by two sandwich aluminum pastes was proposed for EMI monitoring. The workability of the AEP was first verified via finite element analysis, where the effect of hydration heat on the EMI signature of the AEP was evaluated via numerical modeling and prior thermal test. In the experiment, totally four AEP transducers arranged at different loci were applied to monitor strength gain in a mass concrete specimen. As a comparison, the maturity method was also performed to estimate the strength of the specimen. Characteristics of EMI signature and its statistical indices including root mean square deviation (RMSD) and mean absolute percentage deviation (MAPD) were analyzed and correlated to strength development in mass concrete. Monitoring results indicated that the AEP transducers were capable of identifying the strength gain of mass concrete. The logarithmic function between the RMSD/MAPD index values and compressive strength perfectly predicted the strength development, which could be further employed for real‐life and in situ applications.
{"title":"Monitoring of compressive strength gain in mass concrete using embedded piezoelectric transducers","authors":"Demi Ai, Chaokun Chen, Hongping Zhu","doi":"10.1002/tal.2162","DOIUrl":"https://doi.org/10.1002/tal.2162","url":null,"abstract":"This study extended the electromechanical impedance (EMI) technique to monitor the 28‐day age of strength gain in mass concrete, although it has been validated in strength monitoring of a lab‐scaled concrete specimen. Embedded piezoelectric (PZT) transducer, namely, aluminum embedded PZT (AEP), that was wrapped by two sandwich aluminum pastes was proposed for EMI monitoring. The workability of the AEP was first verified via finite element analysis, where the effect of hydration heat on the EMI signature of the AEP was evaluated via numerical modeling and prior thermal test. In the experiment, totally four AEP transducers arranged at different loci were applied to monitor strength gain in a mass concrete specimen. As a comparison, the maturity method was also performed to estimate the strength of the specimen. Characteristics of EMI signature and its statistical indices including root mean square deviation (RMSD) and mean absolute percentage deviation (MAPD) were analyzed and correlated to strength development in mass concrete. Monitoring results indicated that the AEP transducers were capable of identifying the strength gain of mass concrete. The logarithmic function between the RMSD/MAPD index values and compressive strength perfectly predicted the strength development, which could be further employed for real‐life and in situ applications.","PeriodicalId":501238,"journal":{"name":"The Structural Design of Tall and Special Buildings","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141547790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The nonstructural component–structure interaction (NSI) is a critical aspect in addressing the seismic design of structures and nonstructural components. However, the NSI is not considered in generating acceleration spectrum, which is the most commonly used tool for seismic design. To study the pattern of the NSI affecting acceleration response spectra of nonstructural components and floors, the acceleration response spectra of a benchmark steel frame structure with different parameters were calculated using a numerical method after the accuracy of the numerical method was verified by carrying out shaking table tests. These parameters are the damping ratio of the nonstructural component, the weight ratio of the nonstructural components to the floor, and the frequency ratio and height ratio of the nonstructural component to the structure. The influence of each parameter on acceleration response spectra was derived by comparing different spectra. The trend of acceleration response spectra of the nonstructural component with different combinations of parameters was compared to determine whether each parameter is relatively independent. This parametric analysis can be applied to calculating acceleration response spectra of the nonstructural component while considering the NSI.
{"title":"Parametric analysis of nonstructural component acceleration response spectra considering interaction between structures and nonstructural components","authors":"Guowei Zhang, Jincheng Song, Chang'an Qin, Guoliang Sun, Peng Zhuang","doi":"10.1002/tal.2160","DOIUrl":"https://doi.org/10.1002/tal.2160","url":null,"abstract":"The nonstructural component–structure interaction (NSI) is a critical aspect in addressing the seismic design of structures and nonstructural components. However, the NSI is not considered in generating acceleration spectrum, which is the most commonly used tool for seismic design. To study the pattern of the NSI affecting acceleration response spectra of nonstructural components and floors, the acceleration response spectra of a benchmark steel frame structure with different parameters were calculated using a numerical method after the accuracy of the numerical method was verified by carrying out shaking table tests. These parameters are the damping ratio of the nonstructural component, the weight ratio of the nonstructural components to the floor, and the frequency ratio and height ratio of the nonstructural component to the structure. The influence of each parameter on acceleration response spectra was derived by comparing different spectra. The trend of acceleration response spectra of the nonstructural component with different combinations of parameters was compared to determine whether each parameter is relatively independent. This parametric analysis can be applied to calculating acceleration response spectra of the nonstructural component while considering the NSI.","PeriodicalId":501238,"journal":{"name":"The Structural Design of Tall and Special Buildings","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141547749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lian Shen, Yan Han, Peijie Wang, Pinhan Zhou, C. S. Cai, Shuwen Deng
Accurately simulating turbulent wind fields is a significant challenge in wind engineering. This study proposes a novel block‐vorticity method aimed at overcoming the limitations of traditional turbulence generation methods. By superimposing a blocked vortex field at the inlet boundary of large eddy simulation (LES), the proposed method enables the generation of highly precise and anisotropic turbulent wind fields. To validate the effectiveness of the proposed method, the study investigates wind pressures on a high‐rise building structure and performs a comparative analysis with LES narrowband synthesis random flow generator (NSRFG), traditional LES, and SST k‐ω turbulence inlet models. The results demonstrate that the proposed method can effectively simulate turbulence characteristics of atmospheric boundary layer flow, including vortex structure and stochastic fluctuating wind field. Compared to traditional methods, the wind field characteristics of turbulence intensity, instantaneous vorticity, and turbulence self‐equilibrium had obvious advantages over traditional methods. Moreover, the LES vortex method is more accurate in simulating the mean wind pressure and fluctuating wind pressure of the high‐rise building compared to traditional models and is closer to the wind tunnel test results. The proposed method provides an effective approach for generating turbulent wind fields with anisotropic characteristics and can be used to predict the wind‐induced response of civil engineering structures.
精确模拟湍流风场是风能工程中的一项重大挑战。本研究提出了一种新颖的阻塞涡度方法，旨在克服传统湍流生成方法的局限性。通过在大涡模拟（LES）的入口边界叠加阻塞涡场，该方法可生成高精度和各向异性的湍流风场。为了验证所提方法的有效性，研究调查了高层建筑结构的风压，并与 LES 窄带合成随机流发生器 (NSRFG)、传统 LES 和 SST k-ω 湍流入口模型进行了对比分析。结果表明，所提出的方法能有效模拟大气边界层流动的湍流特性，包括涡旋结构和随机波动风场。与传统方法相比，湍流强度、瞬时涡度和湍流自平衡等风场特征具有明显优势。此外，与传统模型相比，LES 涡流法在模拟高层建筑平均风压和波动风压方面更为精确，更接近风洞试验结果。所提出的方法为生成具有各向异性特征的湍流风场提供了一种有效方法，可用于预测土木工程结构的风致响应。
{"title":"Inflow turbulence generator for large eddy simulation based on a novel block‐vorticity vortex method: Application on a tall building wind effect","authors":"Lian Shen, Yan Han, Peijie Wang, Pinhan Zhou, C. S. Cai, Shuwen Deng","doi":"10.1002/tal.2161","DOIUrl":"https://doi.org/10.1002/tal.2161","url":null,"abstract":"Accurately simulating turbulent wind fields is a significant challenge in wind engineering. This study proposes a novel block‐vorticity method aimed at overcoming the limitations of traditional turbulence generation methods. By superimposing a blocked vortex field at the inlet boundary of large eddy simulation (LES), the proposed method enables the generation of highly precise and anisotropic turbulent wind fields. To validate the effectiveness of the proposed method, the study investigates wind pressures on a high‐rise building structure and performs a comparative analysis with LES narrowband synthesis random flow generator (NSRFG), traditional LES, and SST <jats:italic>k</jats:italic>‐<jats:italic>ω</jats:italic> turbulence inlet models. The results demonstrate that the proposed method can effectively simulate turbulence characteristics of atmospheric boundary layer flow, including vortex structure and stochastic fluctuating wind field. Compared to traditional methods, the wind field characteristics of turbulence intensity, instantaneous vorticity, and turbulence self‐equilibrium had obvious advantages over traditional methods. Moreover, the LES vortex method is more accurate in simulating the mean wind pressure and fluctuating wind pressure of the high‐rise building compared to traditional models and is closer to the wind tunnel test results. The proposed method provides an effective approach for generating turbulent wind fields with anisotropic characteristics and can be used to predict the wind‐induced response of civil engineering structures.","PeriodicalId":501238,"journal":{"name":"The Structural Design of Tall and Special Buildings","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141515352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
SummaryIn the context of tall concrete structures, it is crucial to not only control the lateral displacement of the building but also address the issue of differential axial shortenings in its vertical elements. Concrete outriggers, commonly resembling relatively stiff beams spanning one to two floors, connect the central core to exterior columns. The strategic placement and appropriate stiffness of these outriggers at different heights of the structure can significantly influence the overall behavior of the entire structure. This study focuses on optimizing the location, depth, and thickness of concrete outriggers, along with the dimensions of beams and columns, as well as the thickness of the core shear wall with the objective of minimizing construction costs and mitigating the occurrence of lateral displacement and differential axial shortenings within the structure. To achieve this, a combined approach of the Genetic–HookeJeeves algorithm has been employed. In this research, we have integrated HookeJeeves, a local search algorithm, with the genetic algorithm to create a hybrid approach that demonstrates high convergence performance. The structural modeling and analysis were conducted using ETABS finite element software, while a Euro‐International Concrete Committee model (CEB model) was utilized to assess the magnitude of differential axial shortenings, enabling us to approximate the long‐term behavior of concrete. The findings of this study highlight the significant impact of the location and stiffness of outriggers on mitigating both lateral displacement and differential axial shortenings within the structure. Optimal placement of an outrigger resulted in a 16% reduction in lateral displacement, and this value could reach up to 25% when the outrigger possessed the ideal stiffness. Additionally, such an arrangement led to a remarkable 36% decrease in the maximum differential axial shortening observed in the structure. These outcomes demonstrate that meeting the design requirements of the intended structure not only improves its performance but also reduces construction costs by 31%.
{"title":"Multi‐objective optimization design of concrete outriggers based on Genetic–HookeJeeves algorithm: Reducing lateral deflection, differential axial shortening, and construction cost of the structure","authors":"Mahya Safarkhani, Morteza Madhkhan","doi":"10.1002/tal.2157","DOIUrl":"https://doi.org/10.1002/tal.2157","url":null,"abstract":"SummaryIn the context of tall concrete structures, it is crucial to not only control the lateral displacement of the building but also address the issue of differential axial shortenings in its vertical elements. Concrete outriggers, commonly resembling relatively stiff beams spanning one to two floors, connect the central core to exterior columns. The strategic placement and appropriate stiffness of these outriggers at different heights of the structure can significantly influence the overall behavior of the entire structure. This study focuses on optimizing the location, depth, and thickness of concrete outriggers, along with the dimensions of beams and columns, as well as the thickness of the core shear wall with the objective of minimizing construction costs and mitigating the occurrence of lateral displacement and differential axial shortenings within the structure. To achieve this, a combined approach of the Genetic–HookeJeeves algorithm has been employed. In this research, we have integrated HookeJeeves, a local search algorithm, with the genetic algorithm to create a hybrid approach that demonstrates high convergence performance. The structural modeling and analysis were conducted using ETABS finite element software, while a Euro‐International Concrete Committee model (CEB model) was utilized to assess the magnitude of differential axial shortenings, enabling us to approximate the long‐term behavior of concrete. The findings of this study highlight the significant impact of the location and stiffness of outriggers on mitigating both lateral displacement and differential axial shortenings within the structure. Optimal placement of an outrigger resulted in a 16% reduction in lateral displacement, and this value could reach up to 25% when the outrigger possessed the ideal stiffness. Additionally, such an arrangement led to a remarkable 36% decrease in the maximum differential axial shortening observed in the structure. These outcomes demonstrate that meeting the design requirements of the intended structure not only improves its performance but also reduces construction costs by 31%.","PeriodicalId":501238,"journal":{"name":"The Structural Design of Tall and Special Buildings","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141508933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhenzhen Liu, Xiaoxia Ma, Na Li, Juan Chen, Yiyan Lu
SummaryFiber‐reinforced concrete‐filled steel tube (CFST) adopts the microskeleton and bridging effect of fibers, thereby optimizing the confinement effect between the steel tube and concrete core while reducing the concrete core friability. This structure offers a viable solution for solving the interface disengagement and insufficient ductility problems of conventional CFSTs. For further theoretical research and engineering application, the mechanical properties of fiber‐reinforced CFSTs under different loading conditions are reviewed. The research results are summarized, and future research scopes are suggested. The literature review shows that adding fibers improves the ductility of CFSTs significantly but the bearing capacity only slightly. The bond strength between steel tube and concrete core is enhanced by fibers, and the degradation in the bond strength is simultaneously delayed. However, in existing research, the mechanical properties and design method are still inadequate. More experimental works, further theoretical analyses, and numerical simulation should be undertaken to establish the quantitative relations between the generalized fiber parameters and structural performance of CFSTs. Future research should propose a unified design theory of fiber‐reinforced CFST structures based on service performance requirements.
{"title":"Research advances in fiber‐reinforced concrete‐filled steel tube columns","authors":"Zhenzhen Liu, Xiaoxia Ma, Na Li, Juan Chen, Yiyan Lu","doi":"10.1002/tal.2155","DOIUrl":"https://doi.org/10.1002/tal.2155","url":null,"abstract":"SummaryFiber‐reinforced concrete‐filled steel tube (CFST) adopts the microskeleton and bridging effect of fibers, thereby optimizing the confinement effect between the steel tube and concrete core while reducing the concrete core friability. This structure offers a viable solution for solving the interface disengagement and insufficient ductility problems of conventional CFSTs. For further theoretical research and engineering application, the mechanical properties of fiber‐reinforced CFSTs under different loading conditions are reviewed. The research results are summarized, and future research scopes are suggested. The literature review shows that adding fibers improves the ductility of CFSTs significantly but the bearing capacity only slightly. The bond strength between steel tube and concrete core is enhanced by fibers, and the degradation in the bond strength is simultaneously delayed. However, in existing research, the mechanical properties and design method are still inadequate. More experimental works, further theoretical analyses, and numerical simulation should be undertaken to establish the quantitative relations between the generalized fiber parameters and structural performance of CFSTs. Future research should propose a unified design theory of fiber‐reinforced CFST structures based on service performance requirements.","PeriodicalId":501238,"journal":{"name":"The Structural Design of Tall and Special Buildings","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141191385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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