Douglas Mateus de Lima, Iálysson da Silva Medeiros, Romário Barros dos Santos, Luis Ernesto de Medeiros Alas, Pablo Aníbal López‐Yánez
Aiming to achieve efficient structural performance, this article presents a methodology for the design of the shell structure and dimensioning of the connections of an S355J2 tubular steel tower with a height of 80 m, compatible with a SWT‐2.3‐93 wind turbine. The tower is made up of three segments, interconnected by flanged connections made of high‐strength steel. The analysis considers various load cases, taking into account stress and resistance in different directions, as well as designing connections using Petersen's theory, according to maximum strength and fatigue criteria. The results indicate that the circumferential stresses are nearly negligible compared with the resistant stresses, while the shear stress is significantly higher at the base due to the torsional moment. Meridional stress determines the stability of the structure, requiring consideration of internal pressure for safety. Maximum stress values range from 135.00 to 168.47 MPa, depending on the location along the tower height. Flanged connections meet the strength and fatigue criteria, with the first flange enduring 63.0% of the fatigue effect and the second, 39.7%. Therefore, the results provide reliable information and methodologies for tower design, contributing to the practical and efficient development of these structures.
{"title":"Considerations for the structural design of wind turbine towers: A practical application","authors":"Douglas Mateus de Lima, Iálysson da Silva Medeiros, Romário Barros dos Santos, Luis Ernesto de Medeiros Alas, Pablo Aníbal López‐Yánez","doi":"10.1002/tal.2158","DOIUrl":"https://doi.org/10.1002/tal.2158","url":null,"abstract":"Aiming to achieve efficient structural performance, this article presents a methodology for the design of the shell structure and dimensioning of the connections of an S355J2 tubular steel tower with a height of 80 m, compatible with a SWT‐2.3‐93 wind turbine. The tower is made up of three segments, interconnected by flanged connections made of high‐strength steel. The analysis considers various load cases, taking into account stress and resistance in different directions, as well as designing connections using Petersen's theory, according to maximum strength and fatigue criteria. The results indicate that the circumferential stresses are nearly negligible compared with the resistant stresses, while the shear stress is significantly higher at the base due to the torsional moment. Meridional stress determines the stability of the structure, requiring consideration of internal pressure for safety. Maximum stress values range from 135.00 to 168.47 MPa, depending on the location along the tower height. Flanged connections meet the strength and fatigue criteria, with the first flange enduring 63.0% of the fatigue effect and the second, 39.7%. Therefore, the results provide reliable information and methodologies for tower design, contributing to the practical and efficient development of these structures.","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":"141191315","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}
Bin Xue, Wensheng Lu, Yongqiang Yang, Xiangxiang Ren
Under earthquake excitations, the lead core inside the lead‐rubber bearing (LRB) generates heat, causing the mechanical degradation of LRBs. However, the heating effect is not commonly considered in the seismic analysis and design of base‐isolated structures with LRBs, which may underestimate the seismic response of structures, especially under ground motions with certain specific characteristics. This paper aims to reveal the influence of ground motion characteristics on the heating effect and provide useful references for the seismic analysis and design. In this study, the validated LRB model considering heating effect was employed in a base‐isolated building calibrated by testing data. Ground motion characteristics including amplitude, duration, and frequency content were separated by spectrally equivalent and different records. The results indicate that the rate and peak of the lead core temperature rise are strongly correlated to ground motion characteristics. Seismic responses ignoring the heating effect are underestimated, and this underestimate varies as the amplitude, duration, and frequency content change and reaches up to 60% in the studied case. Note that seismic responses of the isolation system are more affected by heating effects than the superstructure, and the duration shows a more significant influence on the stiffness degradation of LRBs than the frequency content. It is strongly recommended that the required duration of ground motions should be raised and the low stories of the superstructure should be reinforced for isolated structures with LRBs. The significant duration indicator DS5–95 is more reasonable than DS5–75 in the analysis of the heating effect.
{"title":"Influence of ground motion characteristics on the heating effect of lead‐rubber bearings in base‐isolated structures","authors":"Bin Xue, Wensheng Lu, Yongqiang Yang, Xiangxiang Ren","doi":"10.1002/tal.2159","DOIUrl":"https://doi.org/10.1002/tal.2159","url":null,"abstract":"Under earthquake excitations, the lead core inside the lead‐rubber bearing (LRB) generates heat, causing the mechanical degradation of LRBs. However, the heating effect is not commonly considered in the seismic analysis and design of base‐isolated structures with LRBs, which may underestimate the seismic response of structures, especially under ground motions with certain specific characteristics. This paper aims to reveal the influence of ground motion characteristics on the heating effect and provide useful references for the seismic analysis and design. In this study, the validated LRB model considering heating effect was employed in a base‐isolated building calibrated by testing data. Ground motion characteristics including amplitude, duration, and frequency content were separated by spectrally equivalent and different records. The results indicate that the rate and peak of the lead core temperature rise are strongly correlated to ground motion characteristics. Seismic responses ignoring the heating effect are underestimated, and this underestimate varies as the amplitude, duration, and frequency content change and reaches up to 60% in the studied case. Note that seismic responses of the isolation system are more affected by heating effects than the superstructure, and the duration shows a more significant influence on the stiffness degradation of LRBs than the frequency content. It is strongly recommended that the required duration of ground motions should be raised and the low stories of the superstructure should be reinforced for isolated structures with LRBs. The significant duration indicator <jats:italic>D</jats:italic><jats:sub>S5–95</jats:sub> is more reasonable than <jats:italic>D</jats:italic><jats:sub>S5–75</jats:sub> in the analysis of the heating effect.","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":"141191384","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}
SummaryMore and more prefabricated steel–concrete hybrid wind turbine towers have been built because of their better lateral stiffness than those of the full steel towers, in which epoxy resin joints are commonly adopted at the horizontal joint between two ring units for improving the erection speed. In fact, epoxy resin joints are designed in the same way as dry joints due to the very thin thickness of epoxy resin layer, in which epoxy resin only acts as a leveling blanket and sealer for jointing and compensates for the unevenness of the contact surface between two ring units. The current design method for the resistance to torsional moment at the horizontal joint is not reasonable because of the unreasonable assumption of Saint‐Venant's torsional theory. The integral expressions of the ultimate torsional moment at the horizontal joint with and without shear force are derived, respectively. The solution of the integral expressions for the ultimate torsional moment is realized by Python programming. The refined finite element analyses of two cases are compared with the existing small‐scale tests with segmental aluminum tubes, which verifies the calculation accuracy of the proposed integral method. In the modified integral model of the ultimate torsional moment, a correction term of the resistance to torsional moment and a more suitable distribution of shear stress under the action of horizontal shear force are proposed to obtain a more accurate ultimate torsional moment. Finally, 36 sets of cases with typical dimensions and axial forces in practical engineering are analyzed by the proposed integral model in the absence of horizontal shear force. One six‐parameter model for calculating the ultimate torsional moment is fitted by the least square method. A discount factor is proposed to consider the influence of the horizontal shear force on the ultimate torsional moment.
{"title":"Ultimate torsional moment of dry horizontal joint for prefabricated concrete tower","authors":"Junling Chen, Wenmin Lin, Jinwei Li","doi":"10.1002/tal.2156","DOIUrl":"https://doi.org/10.1002/tal.2156","url":null,"abstract":"SummaryMore and more prefabricated steel–concrete hybrid wind turbine towers have been built because of their better lateral stiffness than those of the full steel towers, in which epoxy resin joints are commonly adopted at the horizontal joint between two ring units for improving the erection speed. In fact, epoxy resin joints are designed in the same way as dry joints due to the very thin thickness of epoxy resin layer, in which epoxy resin only acts as a leveling blanket and sealer for jointing and compensates for the unevenness of the contact surface between two ring units. The current design method for the resistance to torsional moment at the horizontal joint is not reasonable because of the unreasonable assumption of Saint‐Venant's torsional theory. The integral expressions of the ultimate torsional moment at the horizontal joint with and without shear force are derived, respectively. The solution of the integral expressions for the ultimate torsional moment is realized by Python programming. The refined finite element analyses of two cases are compared with the existing small‐scale tests with segmental aluminum tubes, which verifies the calculation accuracy of the proposed integral method. In the modified integral model of the ultimate torsional moment, a correction term of the resistance to torsional moment and a more suitable distribution of shear stress under the action of horizontal shear force are proposed to obtain a more accurate ultimate torsional moment. Finally, 36 sets of cases with typical dimensions and axial forces in practical engineering are analyzed by the proposed integral model in the absence of horizontal shear force. One six‐parameter model for calculating the ultimate torsional moment is fitted by the least square method. A discount factor is proposed to consider the influence of the horizontal shear force on the ultimate torsional moment.","PeriodicalId":501238,"journal":{"name":"The Structural Design of Tall and Special Buildings","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141191207","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}
SummaryTo better meet the evolving requirements of industrialized building system, this paper introduces a novel approach by proposing the utilization of a plate‐reinforced composite (PRC) coupling beam, which incorporates a steel bar truss deck as a substitute for the conventional reinforced concrete (RC) slab. In order to study the effect of different types of RC slabs on the performance of PRC coupling beams, the low‐cyclic reversed loading test was carried out on three PRC coupling beams. The differences of failure modes, load bearing capacity, stiffness degradation, and energy dissipation capacity of each coupling beam are analyzed. The finite element software ABAQUS is used to analyze the stress distribution in the concrete, steel plate, and reinforcement skeleton of the novel coupling beam. The results show that the incorporation of a steel bar truss deck in PRC coupling beams with a small span‐to‐depth ratio can effectively enhance their shear bearing capacity and energy dissipation capacity. The inclusion of a slab significantly enhances the load‐bearing capacity of the coupling beam, while the utilization of a steel bar truss deck in PRC coupling beams greatly improves their overall bearing capacity. The PRC coupling beams featuring a steel bar truss deck exhibit superior load capacity compared to those with conventional RC slabs. The cumulative energy dissipation at the damage point in PRC beams with a steel bar truss deck is 1.39 times greater than that of the coupling beam without slabs and 1.18 times higher than that of the coupling beam with traditional RC slabs.
{"title":"Seismic behavior of plate‐reinforced composite coupling beams with steel bar truss deck","authors":"Jianbo Tian, Gaoju Liu, Bolin Li, Yuanyuan Xia, Wenjing Zhou, Gang Liang","doi":"10.1002/tal.2154","DOIUrl":"https://doi.org/10.1002/tal.2154","url":null,"abstract":"SummaryTo better meet the evolving requirements of industrialized building system, this paper introduces a novel approach by proposing the utilization of a plate‐reinforced composite (PRC) coupling beam, which incorporates a steel bar truss deck as a substitute for the conventional reinforced concrete (RC) slab. In order to study the effect of different types of RC slabs on the performance of PRC coupling beams, the low‐cyclic reversed loading test was carried out on three PRC coupling beams. The differences of failure modes, load bearing capacity, stiffness degradation, and energy dissipation capacity of each coupling beam are analyzed. The finite element software ABAQUS is used to analyze the stress distribution in the concrete, steel plate, and reinforcement skeleton of the novel coupling beam. The results show that the incorporation of a steel bar truss deck in PRC coupling beams with a small span‐to‐depth ratio can effectively enhance their shear bearing capacity and energy dissipation capacity. The inclusion of a slab significantly enhances the load‐bearing capacity of the coupling beam, while the utilization of a steel bar truss deck in PRC coupling beams greatly improves their overall bearing capacity. The PRC coupling beams featuring a steel bar truss deck exhibit superior load capacity compared to those with conventional RC slabs. The cumulative energy dissipation at the damage point in PRC beams with a steel bar truss deck is 1.39 times greater than that of the coupling beam without slabs and 1.18 times higher than that of the coupling beam with traditional RC slabs.","PeriodicalId":501238,"journal":{"name":"The Structural Design of Tall and Special Buildings","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141169803","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 prestressed anchor bolt system is a reasonable connection mode between the upper steel tower and the bottom concrete foundation for multi‐megawatt wind turbines. This prestressed anchor bolt connection with forged flanges has a similar form to the prestressed high‐strength bolt connection with forged flanges between steel tubes for the tower. However, their mechanical performances have a great difference because of the influence of the stiffness of the anchorage zone in the concrete foundation. Based on the Petersen's method, the engineering calculation method of the prestressed anchor bolt system for wind turbine foundation is derived. The tensile force of the anchor bolt, the anchorage stiffness and clamping force of the base are all deduced according to the theories of mechanics of materials. The numerical models of the segment foundation with the unfavorable anchor bolt and the overall foundation with all anchor bolts are developed for researching the influence of the spatial effect of adjacent segments on the restraint stiffness of the concrete foundation. The numerical analyses of four engineering cases designed by engineering calculation method are carried out for verifying the effectiveness of engineering calculation method. The analysis results show the spatial effect of adjacent segments can be neglected and the Petersen's method can be directly applied for the design of the prestressed anchor bolt system for wind turbine foundation in engineering practice. The engineering calculation method meets the accuracy requirements in engineering practice and can be used to design the prestressed anchor bolt system of wind turbine foundation.
{"title":"Design method of prestressed anchor bolt system for wind turbine foundation","authors":"Junling Chen, Yanchen Wang, Youquan Feng","doi":"10.1002/tal.2153","DOIUrl":"https://doi.org/10.1002/tal.2153","url":null,"abstract":"The prestressed anchor bolt system is a reasonable connection mode between the upper steel tower and the bottom concrete foundation for multi‐megawatt wind turbines. This prestressed anchor bolt connection with forged flanges has a similar form to the prestressed high‐strength bolt connection with forged flanges between steel tubes for the tower. However, their mechanical performances have a great difference because of the influence of the stiffness of the anchorage zone in the concrete foundation. Based on the Petersen's method, the engineering calculation method of the prestressed anchor bolt system for wind turbine foundation is derived. The tensile force of the anchor bolt, the anchorage stiffness and clamping force of the base are all deduced according to the theories of mechanics of materials. The numerical models of the segment foundation with the unfavorable anchor bolt and the overall foundation with all anchor bolts are developed for researching the influence of the spatial effect of adjacent segments on the restraint stiffness of the concrete foundation. The numerical analyses of four engineering cases designed by engineering calculation method are carried out for verifying the effectiveness of engineering calculation method. The analysis results show the spatial effect of adjacent segments can be neglected and the Petersen's method can be directly applied for the design of the prestressed anchor bolt system for wind turbine foundation in engineering practice. The engineering calculation method meets the accuracy requirements in engineering practice and can be used to design the prestressed anchor bolt system of wind turbine foundation.","PeriodicalId":501238,"journal":{"name":"The Structural Design of Tall and Special Buildings","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141109177","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}
For super high‐rise buildings with a height of more than 400 m, differential settlement control of foundation is a crucial aspect in structural design. In previous engineering cases, except that the foundation or piles can be directly supported on bedrock, basement wing walls were commonly used to coordinate the differential settlement of foundation between the perimeter columns and the core. However, wing walls could also have negative effects on the basement usage. This article studied and compared the effects of arranging basement wing walls and adjusting pile length on differential settlement of the foundation. The scheme of adjusting pile length considering the interaction between piles, foundation, and superstructure was proposed to control differential settlement of the foundation, and the effectiveness of canceling basement wing walls was verified. Subsequently, a calculation program was developed to automatically optimize pile lengths by region. Finally, the above achievements were applied to the project of China International Silk Road Center Building with a building height of 498 m, making it the tallest building in China located on nonrock stratum and without basement wing walls.
{"title":"Basement structural design innovation of China International Silk Road Center","authors":"ZhongJun Yu, Jianfeng Wang, Zhibing Zou","doi":"10.1002/tal.2152","DOIUrl":"https://doi.org/10.1002/tal.2152","url":null,"abstract":"For super high‐rise buildings with a height of more than 400 m, differential settlement control of foundation is a crucial aspect in structural design. In previous engineering cases, except that the foundation or piles can be directly supported on bedrock, basement wing walls were commonly used to coordinate the differential settlement of foundation between the perimeter columns and the core. However, wing walls could also have negative effects on the basement usage. This article studied and compared the effects of arranging basement wing walls and adjusting pile length on differential settlement of the foundation. The scheme of adjusting pile length considering the interaction between piles, foundation, and superstructure was proposed to control differential settlement of the foundation, and the effectiveness of canceling basement wing walls was verified. Subsequently, a calculation program was developed to automatically optimize pile lengths by region. Finally, the above achievements were applied to the project of China International Silk Road Center Building with a building height of 498 m, making it the tallest building in China located on nonrock stratum and without basement wing walls.","PeriodicalId":501238,"journal":{"name":"The Structural Design of Tall and Special Buildings","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141111034","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 storage safety of edible oil is critical for global and Chinese food security. In this study, a practical underground four‐circle tangential group tank with the steel‐plate and concrete structure based on a grain storage warehouse was firstly introduced, and the measured hoop reinforcement stress of the outer tank wall is discussed. Secondly, a numerical model consistent with the practical underground group tank is established from the measured data. The distribution of the hoop reinforcement stress of the outer tank wall under earth pressure is extracted and analyzed thoroughly. Finally, formulas reflecting the properties of the hoop reinforcement stress distribution are presented based on the theoretical analysis, and their accuracy is verified by comparison with the measured data. It could be conducted from the experimental results and theoretical formulas that the outer tank wall is under compressive pressure station generally, and the compressive stress increases with the increasing of the ring angle until reaching a steady state. Moreover, the hoop stress curve follows a disproportional function approximately. The moment at 180° hoop with 1‐m plate belt follows the arc‐tangent function while the moment has a sudden‐change point at 120°, which has minor effect on the reinforcement of this tank wall. Consequently, additional attention should be paid to the effects of this sudden‐change phenomenon on the associated structures in in the process of designing of underground storage tanks.
{"title":"Full‐scale experimental and theoretical investigation on wall stress for underground ecological group tanks with four‐circle tangential connections","authors":"Hao Zhang, Yi Sun, Jinping Yang, Lei Chen","doi":"10.1002/tal.2132","DOIUrl":"https://doi.org/10.1002/tal.2132","url":null,"abstract":"The storage safety of edible oil is critical for global and Chinese food security. In this study, a practical underground four‐circle tangential group tank with the steel‐plate and concrete structure based on a grain storage warehouse was firstly introduced, and the measured hoop reinforcement stress of the outer tank wall is discussed. Secondly, a numerical model consistent with the practical underground group tank is established from the measured data. The distribution of the hoop reinforcement stress of the outer tank wall under earth pressure is extracted and analyzed thoroughly. Finally, formulas reflecting the properties of the hoop reinforcement stress distribution are presented based on the theoretical analysis, and their accuracy is verified by comparison with the measured data. It could be conducted from the experimental results and theoretical formulas that the outer tank wall is under compressive pressure station generally, and the compressive stress increases with the increasing of the ring angle until reaching a steady state. Moreover, the hoop stress curve follows a disproportional function approximately. The moment at 180° hoop with 1‐m plate belt follows the arc‐tangent function while the moment has a sudden‐change point at 120°, which has minor effect on the reinforcement of this tank wall. Consequently, additional attention should be paid to the effects of this sudden‐change phenomenon on the associated structures in in the process of designing of underground storage tanks.","PeriodicalId":501238,"journal":{"name":"The Structural Design of Tall and Special Buildings","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141115668","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}
Giulia Di Giovanni, Davide Bernardini, P. Di Re, D. Ruta
In 2005, Moon proposed to equip tall buildings with movable façades to improve structural performance. Previous studies showed that, although this could be very effective in mitigating wind‐induced vibrations, its applicability is limited, as façades tend to exhibit excessive relative displacements. To solve this issue, two improvements are proposed in this work. First, the original idea of a monolithic façade is generalized to a Multiblock Movable Façade (MMF) where the external building skin is segmented into several independent blocks. Second, a friction slider equipped with bumpers is used to realize a dissipative connection capable of limiting the displacements of the façade. To evaluate the applicability of these ideas, the case study of a tall building (the Isozaki tower in Milan, Italy) is considered. Dissipative sliders are modeled as nonlinear hysteretic elements incorporated into a finite element model of the building. Numerical simulations of the dynamical effects of wind‐actions are carried out to compare the performances of the building with and without MMF. The results show that the actions transmitted to the building by the façade can be tuned by properly setting the characteristics of the MMF system to achieve satisfactory performance in terms of maximum displacements and accelerations.
{"title":"Dynamical performances of a wind‐excited high‐rise structure equipped with a multiblock movable faca̧de","authors":"Giulia Di Giovanni, Davide Bernardini, P. Di Re, D. Ruta","doi":"10.1002/tal.2133","DOIUrl":"https://doi.org/10.1002/tal.2133","url":null,"abstract":"In 2005, Moon proposed to equip tall buildings with movable façades to improve structural performance. Previous studies showed that, although this could be very effective in mitigating wind‐induced vibrations, its applicability is limited, as façades tend to exhibit excessive relative displacements. To solve this issue, two improvements are proposed in this work. First, the original idea of a monolithic façade is generalized to a Multiblock Movable Façade (MMF) where the external building skin is segmented into several independent blocks. Second, a friction slider equipped with bumpers is used to realize a dissipative connection capable of limiting the displacements of the façade. To evaluate the applicability of these ideas, the case study of a \u0000 tall building (the Isozaki tower in Milan, Italy) is considered. Dissipative sliders are modeled as nonlinear hysteretic elements incorporated into a finite element model of the building. Numerical simulations of the dynamical effects of wind‐actions are carried out to compare the performances of the building with and without MMF. The results show that the actions transmitted to the building by the façade can be tuned by properly setting the characteristics of the MMF system to achieve satisfactory performance in terms of maximum displacements and accelerations.","PeriodicalId":501238,"journal":{"name":"The Structural Design of Tall and Special Buildings","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141119639","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}
Tuned mass damper (TMD) is a seismic vibration control device used to reduce wind and seismic vibrations of structures. Although TMD is attractive to many researchers due to its simplicity, optimizing its parameters and positions is very challenging. The sensitivity of TMD to structure's frequency changes is among its weaknesses and if parameters of this system are not optimally tuned, the efficiency of this system decreases. To solve this problem, multiple tuned mass dampers (MTMDs) have been proposed. In this research, in order to study and compare single tuned mass damper (STMD) with MTMDs vertically distributed according to modal analysis, a 20‐story building is used. The structure is analyzed in OpenSees under seven ground motions with a peak ground acceleration (PGA) of 1.0 g. To optimize TMD parameters, particle swarm optimization (PSO) algorithm is used and the results are compared to those obtained from Den Hartog's approach. To be able to use PSO algorithm and optimize TMD design parameters, Matlab and OpenSees are linked together. In this paper, more than one vibration mode is used to tune and distribute dampers to overcome higher mode effects in high‐rise buildings. The results showed that depending on their different layouts and different optimization methods used, MTMDs reduce the average maximum responses of the structure by up to 12.1%. This is while STMD is able to reduce maximum responses of the structure by 4.3%.
{"title":"Seismic control of tall buildings using vertically distributed multiple tuned mass dampers","authors":"Ali Akhlagh Pasand, S. M. Zahrai","doi":"10.1002/tal.2123","DOIUrl":"https://doi.org/10.1002/tal.2123","url":null,"abstract":"Tuned mass damper (TMD) is a seismic vibration control device used to reduce wind and seismic vibrations of structures. Although TMD is attractive to many researchers due to its simplicity, optimizing its parameters and positions is very challenging. The sensitivity of TMD to structure's frequency changes is among its weaknesses and if parameters of this system are not optimally tuned, the efficiency of this system decreases. To solve this problem, multiple tuned mass dampers (MTMDs) have been proposed. In this research, in order to study and compare single tuned mass damper (STMD) with MTMDs vertically distributed according to modal analysis, a 20‐story building is used. The structure is analyzed in OpenSees under seven ground motions with a peak ground acceleration (PGA) of 1.0 g. To optimize TMD parameters, particle swarm optimization (PSO) algorithm is used and the results are compared to those obtained from Den Hartog's approach. To be able to use PSO algorithm and optimize TMD design parameters, Matlab and OpenSees are linked together. In this paper, more than one vibration mode is used to tune and distribute dampers to overcome higher mode effects in high‐rise buildings. The results showed that depending on their different layouts and different optimization methods used, MTMDs reduce the average maximum responses of the structure by up to 12.1%. This is while STMD is able to reduce maximum responses of the structure by 4.3%.","PeriodicalId":501238,"journal":{"name":"The Structural Design of Tall and Special Buildings","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141119636","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}
Binyang Li, Yuanlong Yang, Jiepeng Liu, Yu Cheng, Y. Chen
Special‐shaped concrete‐filled steel tubular (SCFST) columns have recently been developed for efficient steel‐concrete composite construction. In this study, a novel vertical stiffener joint for the SCFST column and steel beam frame structure is proposed. Five SCFST columns with H‐section beam joints were investigated under cycling loading. The test parameters mainly consider the column stiffening form, vertical stiffener type, and the column axial load. The failure pattern, hysteretic curves, and strain development of specimens are analyzed. Experimental results demonstrate the proposed joint with vertical stiffeners can develop the steel beam's full plastic flexural capacity and exhibit favorable seismic performance. In addition, a finite element (FE) model is developed to explore the effects of the following parameters on the hysteretic performance: vertical stiffener sizes, width‐to‐thickness ratio of column steel tube, and the column axial load. Based on the experimental and FE analyses, a stress and deformation model of the joint steel tube was established. To facilitate the practical applications, a calculation formula for joint strength was also put forward, considering the contribution of vertical stiffener, and front and side steel plates of the joint steel tube.
最近开发出了用于高效钢-混凝土复合结构的异形混凝土填充钢管（SCFST）柱。本研究为 SCFST 柱和钢梁框架结构提出了一种新型垂直加劲连接。在循环荷载作用下，对五根带有 H 型截面梁连接件的 SCFST 柱进行了研究。试验参数主要考虑了柱加劲形式、竖向加劲件类型和柱轴向荷载。分析了试件的破坏模式、滞后曲线和应变发展。实验结果表明，所提出的带竖向加劲件的连接能充分发挥钢梁的塑性抗弯能力，并表现出良好的抗震性能。此外，还建立了一个有限元（FE）模型，以探讨以下参数对滞后性能的影响：垂直加劲件尺寸、柱钢管的宽厚比和柱轴向荷载。在实验和 FE 分析的基础上，建立了连接钢管的应力和变形模型。为便于实际应用，考虑到竖向加劲件、连接钢管前钢板和侧钢板的作用，还提出了连接强度的计算公式。
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