The Experts below are selected from a list of 390 Experts worldwide ranked by ideXlab platform
Mingzhou Su - One of the best experts on this subject based on the ideXlab platform.
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Finite element analysis for the seismic performance of steel frame-tube structures with replaceable Shear Links
Steel and Composite Structures, 2020Co-Authors: Ming Lian, Hao Zhang, Qianqian Cheng, Mingzhou SuAbstract:In steel frame-tube structures (SFTSs) the application of flexural beam is not suitable for the beam with span-to-depth ratio lower than five because the plastic hinges at beam-ends can not be developed properly. This can lead to lower ductility and energy dissipation capacity of the SFTS. To address this problem, a replaceable Shear Link, acting as a ductile fuse at the mid length of deep beams, is proposed. SFTS with replaceable Shear Links (SFTS-RSLs) dissipate seismic energy through Shear deformation of the Link. In order to evaluate this proposal, buildings were designed to compare the seismic performance of SFTS-RSLs and SFTSs. Several sub-structures were selected from the design buildings and finite element models (FEMs) were established to study their hysteretic behavior. Static pushover and dynamic analyses were undertaken in comparing seismic performance of the FEMs for each building. The results indicated that the SFTS-RSL and SFTS had similar initial lateral stiffness. Compared with SFTS, SFTS-RSL had lower yield strength and maximum strength, but higher ductility and energy dissipation capacity. During earthquakes, SFTS-RSL had lower interstory drift, maximum base Shear force and story Shear force compared with the SFTS. Placing a Shear Link at the beam mid-span did not increase Shear lag effects for the structure. The SFTS-RSL concentrates plasticity on the Shear Link. Other structural components remain elastic during seismic loading. It is expected that the SFTS-RSL will be a reliable dual resistant system. It offers the benefit of being able to repair the structure by replacing damaged Shear Links after earthquakes.
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Numerical study of the seismic behavior of steel frame-tube structures with bolted web-connected replaceable Shear Links
Steel and Composite Structures, 2020Co-Authors: Ming Lian, Hao Zhang, Qianqian Cheng, Mingzhou SuAbstract:Beams of steel frame-tube structures (SFTSs) typically have span-to-depth ratios of less than five. This makes a flexural beam unsuitable for such an application because the plastic hinges at the beam-ends cannot be adequately developed. This leads to lower ductility and energy dissipation capacities of SFTSs. To address this, SFTSs with bolted web-connected replaceable Shear Links (SFTS-BWSLs) are proposed. In this structural system, a web-connected replaceable Shear Link with a back-to-back double channel section is placed at the mid-length of the deep beam to act as a ductile fuse. This allows energy from earthquakes to be dissipated through Link Shear deformation. SFTS and SFTS-BWSL buildings were examined in this study. Several sub-structures were selected from each designed building and finite element models were established to study their respective hysteretic performance. The seismic behavior of each designed building was observed through static and dynamic analyses. The results indicate that the SFTS-BWSL and SFTS have similar initial lateral stiffness and Shear leg properties. The SFTS-BWSL had lower strength, but higher ductility and energy dissipation capacities. Compared to the SFTS, the SFTS-BWSL had lower interstory drift, base Shear force, and story Shear force during earthquakes. This design approach could concentrate plasticity on the Shear Link while maintaining the residual interstory drift at less than 0.5%. The SFTS-BWSL is a reliable resistant system that can be repaired by replacing Shear Links damaged due to earthquakes.
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Spatial substructure hybrid simulation tests of high-strength steel composite Y-eccentrically braced frames
Steel and Composite Structures, 2020Co-Authors: Tengfei Li, Mingzhou SuAbstract:High-strength steel composite Y-eccentrically braced frame (Y-HSS-EBF) is a novel structural system. In this study, the spatial substructure hybrid simulation test (SHST) method is used to further study the seismic performance of Y-HSS-EBF. Firstly, based on the cyclic loading tests of two single-story single-span Y-HSS-EBF planar specimens, a finite element model in OpenSees was verified to provide a reference for the numerical substructure analysis model for the later SHST. Then, the SHST was carried out on the OpenFresco test platform. A three-story spatial Y-HSS-EBF model was taken as the prototype, the top story was taken as the experimental substructure, and the remaining two stories were taken as the numerical substructure to be simulated in OpenSees. According to the test results, the validity of the SHST was verified, and the main seismic performance indexes of the SHST model were analyzed. The results show that, the SHST based on the OpenFresco platform has good stability and accuracy, and the results of the SHST agree well with the global numerical model of the structure. Under strong seismic action, the plastic deformation of Y-HSS-EBF mainly occurs in the Shear Link, and the beam, beam-columns and braces can basically remain in the elastic state, which is conducive to post-earthquake repair.
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Study on the seismic performance of high-strength steel framed-tube structures with replaceable Shear Links
Journal of Constructional Steel Research, 2020Co-Authors: Hao Zhang, Ming Lian, Mingzhou SuAbstract:Abstract In this paper, a high-strength steel framed-tube structure with replaceable Shear Links (HSS-FTS-RSL) was proposed to improve the seismic performance and recoverability of steel framed-tube structures (SFTS), by introducing the Shear Link—acting as a sacrificial component—at the mid-span of a deep beam in order to sustain inelastic deformation and dissipate seismic energy. The preliminary design methodologies for the HSS-FTS-RSL and layout principles of the replaceable Link were introduced. Six prototype 30-story HSS-FTS-RSL buildings with various layouts of the Links and a corresponding conventional SFTS building were designed based on the latest design standards, and their nonlinear numerical models were developed in OpenSees. The modeling approach was verified on experimental data. Nonlinear dynamic analyses were conducted to investigate the feasibility and seismic behavior of HSS-FTS-RSLs. The results indicate that the HSS-FTS-RSL exhibited a superior energy dissipation capacity and lower permanent drifts compared with the conventional SFTS under severe ground motions. In the HSS-FTS-RSL, employing the Shear Link did not increase the Shear lag effect compared with the SFTS. The HSS-FTS-RSLs with various layouts of replaceable Links had almost identical fundamental natural periods, but the layout of the replaceable Link had a significant effect on their seismic behavior. The inelastic deformation of HSS-FTS-RSL was concentrated in the Shear Links, whereas deep beams and columns experienced minor or no damage. Therefore, it can be concluded that the HSS-FTS-RSL was a reliable earthquake-resilient structural system that can be quickly recovered by replacing the damaged Links after a major earthquake.
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Numerical modeling of high-strength steel composite K-eccentrically braced frames and spatial substructure hybrid simulation tests
Bulletin of Earthquake Engineering, 2019Co-Authors: Tengfei Li, Mingzhou SuAbstract:Substructure hybrid simulation test (SHST) is a novel seismic experimental method for analyzing structures, which usually divides the global structure into two components: the experimental substructure and the numerical substructure. An SHST system based on the OpenFresco platform was established. To ensure the high accuracy of the numerical substructure in SHST, a finite element model that corresponded to a quasi-static experimental investigation on high-strength steel composite K-shaped eccentrically braced frame (K-HSS-EBF) was established and analyzed using OpenSees. A three-story and five-span spatial K-HSS-EBF was used as the prototype and the three-story steel frame with a K-eccentric brace on the left second span was taken as the experimental substructure. The remaining four-span was modeled as a numerical substructure in OpenSees. SHST was performed with a half-scale hybrid simulation model. According to the test results, the displacement loading precision of the experimental substructure was analyzed. In addition, the Shear Link rotations of the experimental and numerical substructures were compared. The time curve of the displacement and the base Shear of the hybrid simulation model were also compared with the simulation results of the global numerical model. The results revealed that the seismic response characteristics of the K-HSS-EBF were successfully recaptured using the numerical substructure model established in OpenSees and the spatial SHST system based on OpenFresco.
Tengfei Li - One of the best experts on this subject based on the ideXlab platform.
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Spatial substructure hybrid simulation tests of high-strength steel composite Y-eccentrically braced frames
Steel and Composite Structures, 2020Co-Authors: Tengfei Li, Mingzhou SuAbstract:High-strength steel composite Y-eccentrically braced frame (Y-HSS-EBF) is a novel structural system. In this study, the spatial substructure hybrid simulation test (SHST) method is used to further study the seismic performance of Y-HSS-EBF. Firstly, based on the cyclic loading tests of two single-story single-span Y-HSS-EBF planar specimens, a finite element model in OpenSees was verified to provide a reference for the numerical substructure analysis model for the later SHST. Then, the SHST was carried out on the OpenFresco test platform. A three-story spatial Y-HSS-EBF model was taken as the prototype, the top story was taken as the experimental substructure, and the remaining two stories were taken as the numerical substructure to be simulated in OpenSees. According to the test results, the validity of the SHST was verified, and the main seismic performance indexes of the SHST model were analyzed. The results show that, the SHST based on the OpenFresco platform has good stability and accuracy, and the results of the SHST agree well with the global numerical model of the structure. Under strong seismic action, the plastic deformation of Y-HSS-EBF mainly occurs in the Shear Link, and the beam, beam-columns and braces can basically remain in the elastic state, which is conducive to post-earthquake repair.
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Numerical modeling of high-strength steel composite K-eccentrically braced frames and spatial substructure hybrid simulation tests
Bulletin of Earthquake Engineering, 2019Co-Authors: Tengfei Li, Mingzhou SuAbstract:Substructure hybrid simulation test (SHST) is a novel seismic experimental method for analyzing structures, which usually divides the global structure into two components: the experimental substructure and the numerical substructure. An SHST system based on the OpenFresco platform was established. To ensure the high accuracy of the numerical substructure in SHST, a finite element model that corresponded to a quasi-static experimental investigation on high-strength steel composite K-shaped eccentrically braced frame (K-HSS-EBF) was established and analyzed using OpenSees. A three-story and five-span spatial K-HSS-EBF was used as the prototype and the three-story steel frame with a K-eccentric brace on the left second span was taken as the experimental substructure. The remaining four-span was modeled as a numerical substructure in OpenSees. SHST was performed with a half-scale hybrid simulation model. According to the test results, the displacement loading precision of the experimental substructure was analyzed. In addition, the Shear Link rotations of the experimental and numerical substructures were compared. The time curve of the displacement and the base Shear of the hybrid simulation model were also compared with the simulation results of the global numerical model. The results revealed that the seismic response characteristics of the K-HSS-EBF were successfully recaptured using the numerical substructure model established in OpenSees and the spatial SHST system based on OpenFresco.
Ming Lian - One of the best experts on this subject based on the ideXlab platform.
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Numerical study of the seismic behavior of steel frame-tube structures with bolted web-connected replaceable Shear Links
Steel and Composite Structures, 2020Co-Authors: Ming Lian, Hao Zhang, Qianqian Cheng, Mingzhou SuAbstract:Beams of steel frame-tube structures (SFTSs) typically have span-to-depth ratios of less than five. This makes a flexural beam unsuitable for such an application because the plastic hinges at the beam-ends cannot be adequately developed. This leads to lower ductility and energy dissipation capacities of SFTSs. To address this, SFTSs with bolted web-connected replaceable Shear Links (SFTS-BWSLs) are proposed. In this structural system, a web-connected replaceable Shear Link with a back-to-back double channel section is placed at the mid-length of the deep beam to act as a ductile fuse. This allows energy from earthquakes to be dissipated through Link Shear deformation. SFTS and SFTS-BWSL buildings were examined in this study. Several sub-structures were selected from each designed building and finite element models were established to study their respective hysteretic performance. The seismic behavior of each designed building was observed through static and dynamic analyses. The results indicate that the SFTS-BWSL and SFTS have similar initial lateral stiffness and Shear leg properties. The SFTS-BWSL had lower strength, but higher ductility and energy dissipation capacities. Compared to the SFTS, the SFTS-BWSL had lower interstory drift, base Shear force, and story Shear force during earthquakes. This design approach could concentrate plasticity on the Shear Link while maintaining the residual interstory drift at less than 0.5%. The SFTS-BWSL is a reliable resistant system that can be repaired by replacing Shear Links damaged due to earthquakes.
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Finite element analysis for the seismic performance of steel frame-tube structures with replaceable Shear Links
Steel and Composite Structures, 2020Co-Authors: Ming Lian, Hao Zhang, Qianqian Cheng, Mingzhou SuAbstract:In steel frame-tube structures (SFTSs) the application of flexural beam is not suitable for the beam with span-to-depth ratio lower than five because the plastic hinges at beam-ends can not be developed properly. This can lead to lower ductility and energy dissipation capacity of the SFTS. To address this problem, a replaceable Shear Link, acting as a ductile fuse at the mid length of deep beams, is proposed. SFTS with replaceable Shear Links (SFTS-RSLs) dissipate seismic energy through Shear deformation of the Link. In order to evaluate this proposal, buildings were designed to compare the seismic performance of SFTS-RSLs and SFTSs. Several sub-structures were selected from the design buildings and finite element models (FEMs) were established to study their hysteretic behavior. Static pushover and dynamic analyses were undertaken in comparing seismic performance of the FEMs for each building. The results indicated that the SFTS-RSL and SFTS had similar initial lateral stiffness. Compared with SFTS, SFTS-RSL had lower yield strength and maximum strength, but higher ductility and energy dissipation capacity. During earthquakes, SFTS-RSL had lower interstory drift, maximum base Shear force and story Shear force compared with the SFTS. Placing a Shear Link at the beam mid-span did not increase Shear lag effects for the structure. The SFTS-RSL concentrates plasticity on the Shear Link. Other structural components remain elastic during seismic loading. It is expected that the SFTS-RSL will be a reliable dual resistant system. It offers the benefit of being able to repair the structure by replacing damaged Shear Links after earthquakes.
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Study on the seismic performance of high-strength steel framed-tube structures with replaceable Shear Links
Journal of Constructional Steel Research, 2020Co-Authors: Hao Zhang, Ming Lian, Mingzhou SuAbstract:Abstract In this paper, a high-strength steel framed-tube structure with replaceable Shear Links (HSS-FTS-RSL) was proposed to improve the seismic performance and recoverability of steel framed-tube structures (SFTS), by introducing the Shear Link—acting as a sacrificial component—at the mid-span of a deep beam in order to sustain inelastic deformation and dissipate seismic energy. The preliminary design methodologies for the HSS-FTS-RSL and layout principles of the replaceable Link were introduced. Six prototype 30-story HSS-FTS-RSL buildings with various layouts of the Links and a corresponding conventional SFTS building were designed based on the latest design standards, and their nonlinear numerical models were developed in OpenSees. The modeling approach was verified on experimental data. Nonlinear dynamic analyses were conducted to investigate the feasibility and seismic behavior of HSS-FTS-RSLs. The results indicate that the HSS-FTS-RSL exhibited a superior energy dissipation capacity and lower permanent drifts compared with the conventional SFTS under severe ground motions. In the HSS-FTS-RSL, employing the Shear Link did not increase the Shear lag effect compared with the SFTS. The HSS-FTS-RSLs with various layouts of replaceable Links had almost identical fundamental natural periods, but the layout of the replaceable Link had a significant effect on their seismic behavior. The inelastic deformation of HSS-FTS-RSL was concentrated in the Shear Links, whereas deep beams and columns experienced minor or no damage. Therefore, it can be concluded that the HSS-FTS-RSL was a reliable earthquake-resilient structural system that can be quickly recovered by replacing the damaged Links after a major earthquake.
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seismic performance of high strength steel fabricated eccentrically braced frame with vertical Shear Link
Journal of Constructional Steel Research, 2017Co-Authors: Ming Lian, Mingzhou SuAbstract:Abstract In high-strength steel fabricated eccentrically braced frame with vertical Shear Link (HSSEBF-VSL), the vertical Shear Links use conventional steel while beam and column use high-strength steel (HSS). Using HSS for beams and columns in HSSEBF-VSL can reduce steel weight and increased economic efficiency. In this paper, static tests for two 1:2 length scaled HSSEBF-VSL specimens with one-bay and one-story were carried out, including one static pushover test and one cyclic loading test. The failure mode, load-bearing, ductility and energy dissipation capacities of the specimens were studied through the two static tests. Shake table test of a 1:2 length scaled three-story HSSEBF-VSL specimen was used to study its dynamic responses and dynamic strain responses of the vertical Shear Links. In addition, the finite element models of several HSSEBF-VSL and conventional EBF with vertical Shear Link (EBF-VSL) buildings were established for seismic effects. Nonlinear pushover and dynamic analyses were conducted to compare their seismic performance and economy. The test results indicated that the specimen with one-bay and one story had reliable lateral stiffness, ductility and energy dissipation capacity. The three-story specimen had good lateral stiffness and there was no dangerous of collapse for the specimen during the severe earthquakes. Under the same design conditions, the seismic performance of HSSEBF-VSL was slightly lower than that of EBF-VSL if it was designed to match the member section strength of EBF-VSL, but it used less steel than that of EBF-VSL, which could reduce the usage amount of steel in HSSEBF-VSL.
Kiarash M Dolatshahi - One of the best experts on this subject based on the ideXlab platform.
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Collapse risk and earthquake-induced loss assessment of buildings with eccentrically braced frames
Journal of Constructional Steel Research, 2020Co-Authors: Omid Moammer, Kiarash M Dolatshahi, Hamid M. Madani, Mehrdad GhyabiAbstract:Abstract In this paper, earthquake-induced economic loss of buildings with the eccentrically braced frame as the lateral load resisting system is investigated. Economic loss in this paper includes collapse loss, demolition loss, and structural and nonstructural repair loss. A simplified probabilistic story-based loss estimation procedure is employed for this purpose. A thorough study is conducted on the verification of Shear Link response with experimental results as Shear Link is the main source of nonlinearity in eccentrically braced frames. Nonlinear response history analyses are conducted on four, eight and sixteen story prototype models and engineering demand parameters such as story drift ratio, peak floor acceleration, Shear Link rotation, and residual story drift ratios are extracted for each story in all analyses. The effect of Shear tab connection in the gravity framing and various design methods, equivalent lateral force and response spectrum analysis, are also investigated on the economic loss. The results show that the buildings with eccentrically braced frames as the lateral resisting system have a superior performance during earthquakes, especially when the effect of gravity framing is included. This is in confirmation with the observations after the 2010/2011 Christchurch earthquake.
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experimental study of steel moment resisting frames with Shear Link
Journal of Constructional Steel Research, 2019Co-Authors: Farid Mahmoudi, Kiarash M Dolatshahi, Mojtaba Mahsuli, M T Nikoukalam, Amir ShahmohammadiAbstract:Abstract Seismic codes specify a minimum beam span-to-depth ratio for moment resisting frames to ensure formation of plastic hinges at beam ends with adequate length. This minimum beam span-to-depth limitation is at odds with the need for shorter spans to control lateral drifts in tall buildings, especially with tubular frames. To ease the limitation, this paper proposes a Shear Link at the beam mid-span, comprising a replaceable beam with a smaller cross-section than that of the main beam. The Shear fuse dissipates energy by Shear yielding and thus, prevents or delays the flexural yielding of beam ends. To examine the proposed idea, a moment resisting frame that violates the minimum beam span-to-depth ratio limitation and a hybrid frame (HF) with the proposed fuse are subjected to cyclic loading in laboratory experiments. The results indicate adequate energy dissipation and stable hysteresis behavior for Specimen HF, thereby eliminating the need to observe the code limitation. Specimen HF shows a ductility capacity twice that of the moment resisting frame with almost the same stiffness and strength. Additionally, replaceability of the fuse enhances the resilience of the proposed system. Finally, a numerical model is developed and verified with the test results for future expansion of the proposed design concept.
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Experimental investigation of slitted web steel moment resisting frame
Journal of Constructional Steel Research, 2018Co-Authors: Kiarash M Dolatshahi, Ali Gharavi, Sayed Rasoul MirghaderiAbstract:Abstract This paper presents the results of three tests to evaluate cyclic behavior of Special Moment Resisting Frames (SMRF) with Slitted web section (SW-MRF). Typically, in SMRFs energy is dissipated by formation of plastic hinges at the beam ends. Nevertheless, based on the recent seismic codes, the span-to-depth ratio of beams in SMRFs should be larger than a minimum value to assure the development of plastic hinges with sufficient length at beam ends, reducing application of short span beams. In this paper, a new approach is proposed for short and medium span beams to transmit the flexural plastic hinges from the beam ends to the beam center by slitting a portion of the beam web at the mid-span and formation of a Shear Link. The idea can be applied for design of new buildings and for the purpose of rehabilitation in the damaged SMRFs. Two single-bay one-story SW-MRFs are constructed and tested under the quasi-static cyclic loading. One test was conducted on a new frame and the other test on an already flexurally damaged frame. This paper describes the specimen design, construction, experimental setup and results of the test. The test results are compared with the corresponding MRF specimen with a similar geometry and material properties. The results indicate that the proposed idea provides a stiff and ductile system via stable hysteretic loops, which makes it a suitable option for the design of new buildings and retrofit of damaged moment resisting frames.
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predictive equations for Shear Link modeling toward collapse
Engineering Structures, 2017Co-Authors: Omid Moammer, Kiarash M DolatshahiAbstract:Abstract In this paper the predictive equations for collapse assessment of Shear Links used in eccentric braced frames are developed. An extensive database including results of over 70 cyclic tests on steel wide flange Shear Links is collected and the structural parameters governing the hysteresis behavior are calibrated using a simplified numerical model. The methodology of calibration is to minimize the discrepancy between the experimental hysteresis loops and the corresponding numerical results using Particle Swarm Optimization (PSO) algorithm. The objective function of PSO algorithm is minimized by iterating parameters that govern the hysteresis behavior of the numerical model. Stepwise multivariable regression is used to present equations for modelling Shear Link behavior parameters. The coefficient of determination for the derived empirical equations shows that the proposed equations can accurately capture the pre-capping, post-capping and cyclic deterioration behavior of the Links for collapse assessments.
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Shear slotted bolted connection
Structural Design of Tall and Special Buildings, 2016Co-Authors: M T Nikoukalam, Seyed Rasoul Mirghaderi, Kiarash M DolatshahiAbstract:Summary Slotted bolted connections (SBCs) have been developed and used as an axial friction damper in braced frames since 1980s. To employ the benefits of SBCs in moment resisting frames (MRFs), rotational slotted bolted connections have been developed more recently with limited application in members that flexural behavior is dominated to Shear. In this paper, Shear slotted bolted connection (SSBC) is introduced as a new type of friction dampers to employ the benefits of SBCs in lateral load resisting systems with predominant Shear behavior members that dissipate energy by traditional yielding mechanisms. The SSBC is a modified bolted connection that dissipates energy through friction in which friction is activated by Shear force. The applications of the proposed system as a Shear Link in Link beams of eccentrically braced frames (EBFs), in the beams of MRFs, and coupling beams of coupled concrete Shear walls are introduced. To show the efficiency of SSBC, an existing EBF with tubular Link beam is equipped with SSBC, and its behavior is studied via models created in general purpose finite element program ABAQUS (SIMULIA, The Dassault Systemes, Realistic Simulation, RI, USA) verified thoroughly against relevant test results. Also, three MRFs with different beam lengths are modified using SSBC, and their monotonic and cyclic behavior are investigated using validated finite element models. The results show that, as expected, SSBC is capable of working as a mechanical Shear fuse dissipating energy effectively in both MRFs and EBFs without any material yielding.
Hao Zhang - One of the best experts on this subject based on the ideXlab platform.
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Finite element analysis for the seismic performance of steel frame-tube structures with replaceable Shear Links
Steel and Composite Structures, 2020Co-Authors: Ming Lian, Hao Zhang, Qianqian Cheng, Mingzhou SuAbstract:In steel frame-tube structures (SFTSs) the application of flexural beam is not suitable for the beam with span-to-depth ratio lower than five because the plastic hinges at beam-ends can not be developed properly. This can lead to lower ductility and energy dissipation capacity of the SFTS. To address this problem, a replaceable Shear Link, acting as a ductile fuse at the mid length of deep beams, is proposed. SFTS with replaceable Shear Links (SFTS-RSLs) dissipate seismic energy through Shear deformation of the Link. In order to evaluate this proposal, buildings were designed to compare the seismic performance of SFTS-RSLs and SFTSs. Several sub-structures were selected from the design buildings and finite element models (FEMs) were established to study their hysteretic behavior. Static pushover and dynamic analyses were undertaken in comparing seismic performance of the FEMs for each building. The results indicated that the SFTS-RSL and SFTS had similar initial lateral stiffness. Compared with SFTS, SFTS-RSL had lower yield strength and maximum strength, but higher ductility and energy dissipation capacity. During earthquakes, SFTS-RSL had lower interstory drift, maximum base Shear force and story Shear force compared with the SFTS. Placing a Shear Link at the beam mid-span did not increase Shear lag effects for the structure. The SFTS-RSL concentrates plasticity on the Shear Link. Other structural components remain elastic during seismic loading. It is expected that the SFTS-RSL will be a reliable dual resistant system. It offers the benefit of being able to repair the structure by replacing damaged Shear Links after earthquakes.
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Numerical study of the seismic behavior of steel frame-tube structures with bolted web-connected replaceable Shear Links
Steel and Composite Structures, 2020Co-Authors: Ming Lian, Hao Zhang, Qianqian Cheng, Mingzhou SuAbstract:Beams of steel frame-tube structures (SFTSs) typically have span-to-depth ratios of less than five. This makes a flexural beam unsuitable for such an application because the plastic hinges at the beam-ends cannot be adequately developed. This leads to lower ductility and energy dissipation capacities of SFTSs. To address this, SFTSs with bolted web-connected replaceable Shear Links (SFTS-BWSLs) are proposed. In this structural system, a web-connected replaceable Shear Link with a back-to-back double channel section is placed at the mid-length of the deep beam to act as a ductile fuse. This allows energy from earthquakes to be dissipated through Link Shear deformation. SFTS and SFTS-BWSL buildings were examined in this study. Several sub-structures were selected from each designed building and finite element models were established to study their respective hysteretic performance. The seismic behavior of each designed building was observed through static and dynamic analyses. The results indicate that the SFTS-BWSL and SFTS have similar initial lateral stiffness and Shear leg properties. The SFTS-BWSL had lower strength, but higher ductility and energy dissipation capacities. Compared to the SFTS, the SFTS-BWSL had lower interstory drift, base Shear force, and story Shear force during earthquakes. This design approach could concentrate plasticity on the Shear Link while maintaining the residual interstory drift at less than 0.5%. The SFTS-BWSL is a reliable resistant system that can be repaired by replacing Shear Links damaged due to earthquakes.
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Study on the seismic performance of high-strength steel framed-tube structures with replaceable Shear Links
Journal of Constructional Steel Research, 2020Co-Authors: Hao Zhang, Ming Lian, Mingzhou SuAbstract:Abstract In this paper, a high-strength steel framed-tube structure with replaceable Shear Links (HSS-FTS-RSL) was proposed to improve the seismic performance and recoverability of steel framed-tube structures (SFTS), by introducing the Shear Link—acting as a sacrificial component—at the mid-span of a deep beam in order to sustain inelastic deformation and dissipate seismic energy. The preliminary design methodologies for the HSS-FTS-RSL and layout principles of the replaceable Link were introduced. Six prototype 30-story HSS-FTS-RSL buildings with various layouts of the Links and a corresponding conventional SFTS building were designed based on the latest design standards, and their nonlinear numerical models were developed in OpenSees. The modeling approach was verified on experimental data. Nonlinear dynamic analyses were conducted to investigate the feasibility and seismic behavior of HSS-FTS-RSLs. The results indicate that the HSS-FTS-RSL exhibited a superior energy dissipation capacity and lower permanent drifts compared with the conventional SFTS under severe ground motions. In the HSS-FTS-RSL, employing the Shear Link did not increase the Shear lag effect compared with the SFTS. The HSS-FTS-RSLs with various layouts of replaceable Links had almost identical fundamental natural periods, but the layout of the replaceable Link had a significant effect on their seismic behavior. The inelastic deformation of HSS-FTS-RSL was concentrated in the Shear Links, whereas deep beams and columns experienced minor or no damage. Therefore, it can be concluded that the HSS-FTS-RSL was a reliable earthquake-resilient structural system that can be quickly recovered by replacing the damaged Links after a major earthquake.