Fragility analysis is an effective tool used to assess the seismic risk of high‐rise buildings. During the process of fragility analysis, determining the engineering demand parameters (EDPs) corresponding to different damage states is of great importance as they directly influence the fragility results. However, for buildings with transfer structures, the EDPs corresponding to different damage levels are difficult to determine since the maximum demand in such buildings is mostly concentrated at the level of irregularity. Obtaining the fragility curves at component level (as used for bridge structures) may provide new insight into the seismic fragility analysis of buildings with transfer structures. Due to differences in structural systems and seismic response, it may be questionable whether such an approach can be directly applied to the fragility analysis of high‐rise buildings. In view of this, a component damage‐based approach suitable for high‐rise buildings and a detailed framework through which to obtain the fragility curves are proposed in this study. This method was applied to assess the seismic risk of a 34‐story concrete building with a transfer plate. The damage states for various structural components were obtained through a damage index (DI) model. The relationship between the DIs of the components and the maximum inter‐story drift ratios (MIDRs) was generated by cloud analysis, and MIDRs corresponding to different component damage states were obtained. The fragility curves at both component and system levels were evaluated. Numerical results indicate that, at the conservative level of PGA (0.2 g), the probability that the main components of the building incur irreparable damage is small, and the performance‐based seismic design requirements can be met.
{"title":"Component damage‐based seismic fragility analysis of high‐rise building with transfer structure","authors":"Kun Liang, R. Su","doi":"10.1002/tal.1985","DOIUrl":"https://doi.org/10.1002/tal.1985","url":null,"abstract":"Fragility analysis is an effective tool used to assess the seismic risk of high‐rise buildings. During the process of fragility analysis, determining the engineering demand parameters (EDPs) corresponding to different damage states is of great importance as they directly influence the fragility results. However, for buildings with transfer structures, the EDPs corresponding to different damage levels are difficult to determine since the maximum demand in such buildings is mostly concentrated at the level of irregularity. Obtaining the fragility curves at component level (as used for bridge structures) may provide new insight into the seismic fragility analysis of buildings with transfer structures. Due to differences in structural systems and seismic response, it may be questionable whether such an approach can be directly applied to the fragility analysis of high‐rise buildings. In view of this, a component damage‐based approach suitable for high‐rise buildings and a detailed framework through which to obtain the fragility curves are proposed in this study. This method was applied to assess the seismic risk of a 34‐story concrete building with a transfer plate. The damage states for various structural components were obtained through a damage index (DI) model. The relationship between the DIs of the components and the maximum inter‐story drift ratios (MIDRs) was generated by cloud analysis, and MIDRs corresponding to different component damage states were obtained. The fragility curves at both component and system levels were evaluated. Numerical results indicate that, at the conservative level of PGA (0.2 g), the probability that the main components of the building incur irreparable damage is small, and the performance‐based seismic design requirements can be met.","PeriodicalId":49470,"journal":{"name":"Structural Design of Tall and Special Buildings","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2022-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43846971","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}
A super tall building named Ningbo Hengda Tower is located in Ningbo City, China. It has 91 stories with a total height of 450 m. The structure system of the building consists of three parts, that is, the reinforced concrete core, the outer frame system, and the outrigger trusses connecting the core wall and outer frame. The unique outer frame system is spindle shaped with oblique columns. The outrigger trusses are located at three different levels above the ground, thus strengthening the building and creating irregularities in the stiffness of the structure along the building height. Great challenges are existed in seismic design and analysis of the building. Shaking table test was carried out for a 1/40 scaled model of the building under a series of different base excitations with increasing amplitudes. The dynamic properties, seismic responses, and failure mechanism of the structure are investigated. Test results show that the structure behaved well under designed level earthquakes. The weak points of the structure are identified based on visible damage of the tested model, and some suggestions are made for the improvement of the seismic behavior of the building. It is suggested that measures be taken to improve the ductility of the building from floor 71 to floor 79 and the adjacent floors.
{"title":"Shaking table test and seismic behavior of Ningbo Hengda Tower","authors":"B. Zhao, Yi-Chian Lin, Xin Li, Ying Zhou","doi":"10.1002/tal.1987","DOIUrl":"https://doi.org/10.1002/tal.1987","url":null,"abstract":"A super tall building named Ningbo Hengda Tower is located in Ningbo City, China. It has 91 stories with a total height of 450 m. The structure system of the building consists of three parts, that is, the reinforced concrete core, the outer frame system, and the outrigger trusses connecting the core wall and outer frame. The unique outer frame system is spindle shaped with oblique columns. The outrigger trusses are located at three different levels above the ground, thus strengthening the building and creating irregularities in the stiffness of the structure along the building height. Great challenges are existed in seismic design and analysis of the building. Shaking table test was carried out for a 1/40 scaled model of the building under a series of different base excitations with increasing amplitudes. The dynamic properties, seismic responses, and failure mechanism of the structure are investigated. Test results show that the structure behaved well under designed level earthquakes. The weak points of the structure are identified based on visible damage of the tested model, and some suggestions are made for the improvement of the seismic behavior of the building. It is suggested that measures be taken to improve the ductility of the building from floor 71 to floor 79 and the adjacent floors.","PeriodicalId":49470,"journal":{"name":"Structural Design of Tall and Special Buildings","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2022-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42451059","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}
Kai-Yi Wu, S. Qian, Huiming Zheng, Yukai Zhou, Ruizhe Zhu
To address the problems faced with steel‐reinforced concrete (SRC) in construction, such as positional conflicts between steel and steel bars or difficulty in pouring concrete, a novel “Steel and Steel Fiber‐Reinforced Concrete” (SSFRC) composite structure was proposed. Push‐out tests of 34 SSFRC composite columns were carried out in this paper to study the interfacial bond performance from the perspective of energy dissipation. Based on loading‐displacement (P‐D) curves, the interfacial energy dissipation (Wb) and energy dissipation factor (λ) were introduced, and the influence of embedded length (Le), steel fiber volume rate (ρsf), thickness of concrete cover (Css), and section type on Wb and λ were analyzed. Test results indicated that circular column is better than square column in terms of Wb and λ. The increase of Le, Css, or ρsf is beneficial to the improvement of Wb, and λ is positively correlated with ρsf and Css but negatively correlated with Le. Additionally, the interfacial damage (Da) was defined by the relationship between elastic deformation energy (Wa) and Wb. It can be concluded that the ascent of Le and Css can effectively delay the appearance of Da and inhibit the development of Da, respectively, and Da develops slowly with the increase of ρsf at the later loading stage.
{"title":"Energy dissipation and damage on the interface of steel and steel fiber‐reinforced concrete composite column","authors":"Kai-Yi Wu, S. Qian, Huiming Zheng, Yukai Zhou, Ruizhe Zhu","doi":"10.1002/tal.1984","DOIUrl":"https://doi.org/10.1002/tal.1984","url":null,"abstract":"To address the problems faced with steel‐reinforced concrete (SRC) in construction, such as positional conflicts between steel and steel bars or difficulty in pouring concrete, a novel “Steel and Steel Fiber‐Reinforced Concrete” (SSFRC) composite structure was proposed. Push‐out tests of 34 SSFRC composite columns were carried out in this paper to study the interfacial bond performance from the perspective of energy dissipation. Based on loading‐displacement (P‐D) curves, the interfacial energy dissipation (Wb) and energy dissipation factor (λ) were introduced, and the influence of embedded length (Le), steel fiber volume rate (ρsf), thickness of concrete cover (Css), and section type on Wb and λ were analyzed. Test results indicated that circular column is better than square column in terms of Wb and λ. The increase of Le, Css, or ρsf is beneficial to the improvement of Wb, and λ is positively correlated with ρsf and Css but negatively correlated with Le. Additionally, the interfacial damage (Da) was defined by the relationship between elastic deformation energy (Wa) and Wb. It can be concluded that the ascent of Le and Css can effectively delay the appearance of Da and inhibit the development of Da, respectively, and Da develops slowly with the increase of ρsf at the later loading stage.","PeriodicalId":49470,"journal":{"name":"Structural Design of Tall and Special Buildings","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2022-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48510638","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}
Shape optimization is an effective tool to improve the aerodynamic performance of tall buildings by introducing minor modifications to the original project. Nevertheless, economic criteria demand efficient cross sections aiming at maximizing the building's profitability. These two contradictory criteria are commonly handled by adopting multi‐objective optimization approaches seeking the definition of Pareto fronts. However, the aerodynamic nonlinear features of low‐aspect‐ratio cross sections typically adopted in architectural practice can cause wind‐induced acceleration response surfaces over the considered design domain with multiple local minima that eventually lead to discontinuous Pareto fronts with non‐convex regions. This study delves into this problem and proposes a design framework that effectively combines the reduced basis method with multi‐objective optimization techniques to carry out the aerodynamic shape optimization using surrogates trained with CFD simulations. The ability of the optimization strategy to properly define the non‐convex regions of discontinuous Pareto fronts is successfully leveraged by adopting the weighted min–max method.
{"title":"Shape optimization of tall buildings cross‐section: Balancing profit and aeroelastic performance","authors":"F. Nieto, M. Cid Montoya, S. Hernández","doi":"10.1002/tal.1982","DOIUrl":"https://doi.org/10.1002/tal.1982","url":null,"abstract":"Shape optimization is an effective tool to improve the aerodynamic performance of tall buildings by introducing minor modifications to the original project. Nevertheless, economic criteria demand efficient cross sections aiming at maximizing the building's profitability. These two contradictory criteria are commonly handled by adopting multi‐objective optimization approaches seeking the definition of Pareto fronts. However, the aerodynamic nonlinear features of low‐aspect‐ratio cross sections typically adopted in architectural practice can cause wind‐induced acceleration response surfaces over the considered design domain with multiple local minima that eventually lead to discontinuous Pareto fronts with non‐convex regions. This study delves into this problem and proposes a design framework that effectively combines the reduced basis method with multi‐objective optimization techniques to carry out the aerodynamic shape optimization using surrogates trained with CFD simulations. The ability of the optimization strategy to properly define the non‐convex regions of discontinuous Pareto fronts is successfully leveraged by adopting the weighted min–max method.","PeriodicalId":49470,"journal":{"name":"Structural Design of Tall and Special Buildings","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49042757","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}
Zongping Chen, C. Song, Ji Zhou, Ni Wang, Yuliang Chen
Steel angle frame reinforced concrete (SARC) beam is a kind of composite beam with encased steel angle frame. The torsion tests were carried out on six SARC beams and one reinforced concrete (RC) beam to investigate their torsional behavior. Test variables include space between steel plates, angle of steel plates, concrete cover depth, and concrete strength. The results showed that the reduction of space between steel plates causes specimens to crack in advance, but improves torsional behavior after cracking markedly. The energy dissipation coefficient reduces as concrete cover depth increases. Damage index can be effectively reduced by increasing concrete strength, reducing plates spacing, and increasing concrete cover depth. The overall torsional behavior of SARC beam can be improved by reducing the spacing between the plates, adopting staggered vertical and oblique steel plates, and increasing concrete strength, but the effect is adverse when concrete cover depth increases. Moreover, the space between steel plates should be greater than 100 mm, and concrete cover depth should be less than 35 mm for maximizing the torsional strength of steel angle frame. Considering the positive roles of steel angle frame and oblique steel plates, the calculation methods of cracking and ultimate torsional moment were proposed. This study can provide a theoretical basis for the engineering application of SARC beams subjected to torsion.
{"title":"Investigation on mechanical behavior of steel angle frame reinforced concrete beams under torsion","authors":"Zongping Chen, C. Song, Ji Zhou, Ni Wang, Yuliang Chen","doi":"10.1002/tal.1981","DOIUrl":"https://doi.org/10.1002/tal.1981","url":null,"abstract":"Steel angle frame reinforced concrete (SARC) beam is a kind of composite beam with encased steel angle frame. The torsion tests were carried out on six SARC beams and one reinforced concrete (RC) beam to investigate their torsional behavior. Test variables include space between steel plates, angle of steel plates, concrete cover depth, and concrete strength. The results showed that the reduction of space between steel plates causes specimens to crack in advance, but improves torsional behavior after cracking markedly. The energy dissipation coefficient reduces as concrete cover depth increases. Damage index can be effectively reduced by increasing concrete strength, reducing plates spacing, and increasing concrete cover depth. The overall torsional behavior of SARC beam can be improved by reducing the spacing between the plates, adopting staggered vertical and oblique steel plates, and increasing concrete strength, but the effect is adverse when concrete cover depth increases. Moreover, the space between steel plates should be greater than 100 mm, and concrete cover depth should be less than 35 mm for maximizing the torsional strength of steel angle frame. Considering the positive roles of steel angle frame and oblique steel plates, the calculation methods of cracking and ultimate torsional moment were proposed. This study can provide a theoretical basis for the engineering application of SARC beams subjected to torsion.","PeriodicalId":49470,"journal":{"name":"Structural Design of Tall and Special Buildings","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2022-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45843993","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}
Kai-Yi Wu, Yanjie Zhang, S. Lin, Q. Liang, S. Qian
According to the construction difficulties in steel reinforced concrete (SRC) structures, rebar cages were discretized into steel fibers to form steel and steel fiber reinforced concrete (SSFRC) structures. The 18 SSFRC beams without rebar cages were tested under bending, and the effect of the steel fiber volume ratio (ρsf), shaped steel ratio (ρss), and shear span ratio (λ) on mechanical properties were investigated. Increasing ρsf could not only turn shearing failure and debonding failure into bending failure, and effectively reduce the sudden decrease of load, but also enhance the bearing capacity, ductility, and damage resistance of specimens to a certain extent. As the ρss ascended, the mechanical properties were obviously improved. However, ρsf should be accordingly increased to avoid adverse effects of excessive ρss. The specimen with small λ had the better bearing and energy dissipation capacity and poor ductility. A large λ meant that ρss and ρsf should be appropriately increased to prevent premature failure of specimens.
{"title":"Experimental study on mechanical properties of steel and steel fiber reinforced concrete beams","authors":"Kai-Yi Wu, Yanjie Zhang, S. Lin, Q. Liang, S. Qian","doi":"10.1002/tal.1979","DOIUrl":"https://doi.org/10.1002/tal.1979","url":null,"abstract":"According to the construction difficulties in steel reinforced concrete (SRC) structures, rebar cages were discretized into steel fibers to form steel and steel fiber reinforced concrete (SSFRC) structures. The 18 SSFRC beams without rebar cages were tested under bending, and the effect of the steel fiber volume ratio (ρsf), shaped steel ratio (ρss), and shear span ratio (λ) on mechanical properties were investigated. Increasing ρsf could not only turn shearing failure and debonding failure into bending failure, and effectively reduce the sudden decrease of load, but also enhance the bearing capacity, ductility, and damage resistance of specimens to a certain extent. As the ρss ascended, the mechanical properties were obviously improved. However, ρsf should be accordingly increased to avoid adverse effects of excessive ρss. The specimen with small λ had the better bearing and energy dissipation capacity and poor ductility. A large λ meant that ρss and ρsf should be appropriately increased to prevent premature failure of specimens.","PeriodicalId":49470,"journal":{"name":"Structural Design of Tall and Special Buildings","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2022-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47430650","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}
Nowadays, the grouted splice sleeve and grouting‐anchoring overlap‐joint of steel bars are widely used as a connection method between precast concrete elements. However, the further development of these connection methods in the engineering is limited because of the high construction cost and complex construction technology in China. Hence, a precast concrete reinforcement connector, that is, double‐pipe connector (D‐P connector) based on strong lapping concept, was proposed, and the feasibility of the D‐P connector was validated by tensile tests, and the failure pattern and mechanical properties of the specimens were observed. Then, the wall panel specimens that connectors were surrounded by concrete were tested to prove the constraint effect of surrounding concrete on the connecting members. Finally, the influences of the parameters, including grout strength, grout height, and connector length, on the failure pattern and mechanical properties of the specimens were investigated. The results show that the influence of the parameters on the performance of the specimens is insignificant, demonstrating that the infill material was mainly used to fix the relative positions of the bar and the D‐P connector. To save cost effectively, high‐strength grout could be replaced by common cement slurry, and the length of D‐P connector could be properly reduced.
{"title":"Experimental test on precast concrete reinforcement connector technology based on strong lapping concept","authors":"Xinlei Yang, Y. Lu, Hu Zhao","doi":"10.1002/tal.1980","DOIUrl":"https://doi.org/10.1002/tal.1980","url":null,"abstract":"Nowadays, the grouted splice sleeve and grouting‐anchoring overlap‐joint of steel bars are widely used as a connection method between precast concrete elements. However, the further development of these connection methods in the engineering is limited because of the high construction cost and complex construction technology in China. Hence, a precast concrete reinforcement connector, that is, double‐pipe connector (D‐P connector) based on strong lapping concept, was proposed, and the feasibility of the D‐P connector was validated by tensile tests, and the failure pattern and mechanical properties of the specimens were observed. Then, the wall panel specimens that connectors were surrounded by concrete were tested to prove the constraint effect of surrounding concrete on the connecting members. Finally, the influences of the parameters, including grout strength, grout height, and connector length, on the failure pattern and mechanical properties of the specimens were investigated. The results show that the influence of the parameters on the performance of the specimens is insignificant, demonstrating that the infill material was mainly used to fix the relative positions of the bar and the D‐P connector. To save cost effectively, high‐strength grout could be replaced by common cement slurry, and the length of D‐P connector could be properly reduced.","PeriodicalId":49470,"journal":{"name":"Structural Design of Tall and Special Buildings","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2022-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49417860","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}
Vincent Harelimana, Yuan Jun Ping, Zhun Gao, Salomon K. A. Umuhuza
Stone columns are used to improve soft soils; however, they fail through bulging, punching, and lateral expansion when the soil is extremely soft. The present study investigated the performance of stone columns in an extremely soft clay (ESC) through the addition of the appropriate geosynthetic materials. Field test was conducted for the foremost purpose of obtaining the optimal spacing between the consecutive stone columns and therefore prevents the failures of stone columns in ESC soils. The study further examined the failure modes of stone columns for the case of ESC soils. The computer programming software FLAC 3D was used for modeling and simulation, while Auto CAD was used to draw needed geometries of the case study. The results revealed that the full encasement of the stone column with suitable geogrids, optimal spacing, and proper design of cushion will enable the efficient use of stone columns as a composite foundation in ESC. The considered appropriate thickness of the cushion was found to be 30 cm, and this cushion helps the embedded soft clay soils to work together with the installed encased stone columns in ESC soils. The center‐to‐center (optimal) spacing between two consecutive stone columns showed optimal performance at distance S ≤ 5d of the diameter of the stone column. These findings show that stone column encased with suitable geogrids and optimal spacing will improve the bearing capacity, reduce settlement, and decrease the lateral deflection as well as hoop strain of the foundation.
{"title":"Investigating the performance of stone columns in an extremely soft clay—A case study","authors":"Vincent Harelimana, Yuan Jun Ping, Zhun Gao, Salomon K. A. Umuhuza","doi":"10.1002/tal.1978","DOIUrl":"https://doi.org/10.1002/tal.1978","url":null,"abstract":"Stone columns are used to improve soft soils; however, they fail through bulging, punching, and lateral expansion when the soil is extremely soft. The present study investigated the performance of stone columns in an extremely soft clay (ESC) through the addition of the appropriate geosynthetic materials. Field test was conducted for the foremost purpose of obtaining the optimal spacing between the consecutive stone columns and therefore prevents the failures of stone columns in ESC soils. The study further examined the failure modes of stone columns for the case of ESC soils. The computer programming software FLAC 3D was used for modeling and simulation, while Auto CAD was used to draw needed geometries of the case study. The results revealed that the full encasement of the stone column with suitable geogrids, optimal spacing, and proper design of cushion will enable the efficient use of stone columns as a composite foundation in ESC. The considered appropriate thickness of the cushion was found to be 30 cm, and this cushion helps the embedded soft clay soils to work together with the installed encased stone columns in ESC soils. The center‐to‐center (optimal) spacing between two consecutive stone columns showed optimal performance at distance S ≤ 5d of the diameter of the stone column. These findings show that stone column encased with suitable geogrids and optimal spacing will improve the bearing capacity, reduce settlement, and decrease the lateral deflection as well as hoop strain of the foundation.","PeriodicalId":49470,"journal":{"name":"Structural Design of Tall and Special Buildings","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47236122","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}
In this study, the ASCE 41‐17 nonlinear static procedure for steel moment‐resisting frames is evaluated using a three‐phase constraint handling procedure. For the first time, advanced performance measures of ASCE 41‐17 are quantified during the optimization process by constructing concentrated plasticity models of the standard. Covariance matrix adaptation in evolution strategies (CMA‐ES) is used to obtain optimal designs for three‐ and nine‐story illustrative examples. Active and inactive constraints are discussed in the current performance‐based design methodology as a guide for future research. The seismic evaluation procedure outlined in FEMA P695 is applied to 147 optimal designs. Plastic hinge models explicitly simulate cyclic deterioration in nonlinear dynamic analyses. The numerical results conclusively demonstrate that the design procedure provides an acceptable margin of safety from collapse of the treated frames. Moreover, there is no significant relationship between the structural weights and the collapse margin ratios for such optimally designed structures.
{"title":"Evaluating ASCE 41‐17 performance‐based provisions on optimally designed steel moment frames","authors":"M. Ebadijalal, M. Shahrouzi","doi":"10.1002/tal.1977","DOIUrl":"https://doi.org/10.1002/tal.1977","url":null,"abstract":"In this study, the ASCE 41‐17 nonlinear static procedure for steel moment‐resisting frames is evaluated using a three‐phase constraint handling procedure. For the first time, advanced performance measures of ASCE 41‐17 are quantified during the optimization process by constructing concentrated plasticity models of the standard. Covariance matrix adaptation in evolution strategies (CMA‐ES) is used to obtain optimal designs for three‐ and nine‐story illustrative examples. Active and inactive constraints are discussed in the current performance‐based design methodology as a guide for future research. The seismic evaluation procedure outlined in FEMA P695 is applied to 147 optimal designs. Plastic hinge models explicitly simulate cyclic deterioration in nonlinear dynamic analyses. The numerical results conclusively demonstrate that the design procedure provides an acceptable margin of safety from collapse of the treated frames. Moreover, there is no significant relationship between the structural weights and the collapse margin ratios for such optimally designed structures.","PeriodicalId":49470,"journal":{"name":"Structural Design of Tall and Special Buildings","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2022-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49107612","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}
Twisted diagrid tube structures have become popular due to their significant lateral resistance and esthetic potential. However, the ductility and energy dissipation capacity of twisted diagrid structures are poor. This paper presents a seismic resilient fused structural system named the twisted diagrids with shear links (TDSL), and the performance‐based plastic design (PBPD) method is introduced for designing a 24‐story prototype structure. The numerical model of the TDSL prototype is established, then nonlinear static and dynamic analyses are conducted to evaluate the seismic behavior of the prototype. The results reveal that the TDSL system can significantly improve the post‐yield performance compared to the conventional twisted diagrid structure, and the performance objectives are achieved properly. Subsequently, incremental dynamic analyses are carried out to investigate the collapse fragility of the TDSL prototype, and the collapse risk of the prototype is assessed by FEMA P695. The results indicate that the TDSL prototype has satisfactory collapse‐resisting capacity under earthquakes. It is also found that corner columns can improve the seismic safety of the prototype against collapse. In general, the TDSL system is an appealing choice for twisted buildings in seismic regions.
{"title":"Performance‐based plastic design and seismic performance evaluation of twisted diagrids with shear links","authors":"S. Song, Chonghou Zhang","doi":"10.1002/tal.1974","DOIUrl":"https://doi.org/10.1002/tal.1974","url":null,"abstract":"Twisted diagrid tube structures have become popular due to their significant lateral resistance and esthetic potential. However, the ductility and energy dissipation capacity of twisted diagrid structures are poor. This paper presents a seismic resilient fused structural system named the twisted diagrids with shear links (TDSL), and the performance‐based plastic design (PBPD) method is introduced for designing a 24‐story prototype structure. The numerical model of the TDSL prototype is established, then nonlinear static and dynamic analyses are conducted to evaluate the seismic behavior of the prototype. The results reveal that the TDSL system can significantly improve the post‐yield performance compared to the conventional twisted diagrid structure, and the performance objectives are achieved properly. Subsequently, incremental dynamic analyses are carried out to investigate the collapse fragility of the TDSL prototype, and the collapse risk of the prototype is assessed by FEMA P695. The results indicate that the TDSL prototype has satisfactory collapse‐resisting capacity under earthquakes. It is also found that corner columns can improve the seismic safety of the prototype against collapse. In general, the TDSL system is an appealing choice for twisted buildings in seismic regions.","PeriodicalId":49470,"journal":{"name":"Structural Design of Tall and Special Buildings","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2022-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46253728","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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