This paper presents a comprehensive framework for life‐cycle carbon emission assessment of steel frame structures in seismic zones, with a particular focus on emerging self‐centering steel structures ...with reduced residual deformation and enhanced seismic resilience. The proposed framework is illustrated through a life‐cycle embodied carbon (EC) emission study on an office building located at Los Angeles, USA. Different structural bracing systems are considered for comparison, namely, conventional concentrically braced frame (CBF), bucking‐restrained braced frame (BRBF), and self‐centering braced frames (SCBFs). The life cycle assessment (LCA) of EC emissions mainly involves four phases: (1) components manufacturing phase, (2) construction phase, (3) operation and maintenance phase, and (4) EC emissions related to seismic hazard. For the last stage, the engineering demand parameter (EDP) is obtained through incremental dynamic analysis (IDA), and combined with the fragility function and the seismic risk curve to obtain the expected EC emissions related to seismic hazard over the life cycle. Among other findings, the results show that: (1) In the manufacturing process, the EC emissions of the emerging SCBFs are slightly increased (by up to 1.4%) compared with the two other conventional steel frames. (2) During the construction, operation, and maintenance phases, there is no difference in the EC emissions for the different structural systems. (3) The EC emissions related to potential seismic risk are reduced by up to 65.3% when the proposed self‐centering structural system (P‐SCBF) is used. (4) Compared with the CBF, the total EC emission over a 100‐year lifespan can be reduced by up to 14.6% when the P‐SCBF is used. Due to the limited deformation capacity of braces, the EC emissions of CBF and BRBF are more sensitive to increases in the intensity measure (IM). Since a building becomes difficult to repair when the maximum residual inter‐story drift exceeds 0.5%, BRBF and CBF are more susceptible to demolition due to unacceptable residual deformation, leading to higher EC emissions. The EC reduction efficiency of the emerging steel frames become more remarkable with increasing life span.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
AbstractThis paper presents the full-scale shake-table test and numerical simulation study results of a 2-story beam-through steel frame (BTSF) equipped with self-centering modular panels (SCMPs) ...subjected to near-fault ground motion records. A SCMP is a portable self-centering device that can be inserted and bolted to steel frames to provide lateral force resistance with recentering capability and replaceable seismic fuse devices for energy dissipation. Previous research works have been done on the analytical study, quasi-static cyclic loading testing, and numerical study of the general seismic behavior of the SCMP systems with different energy dissipation components including tension-only braces, slit steel plate shear walls (SWs), and hysteretic dampers. An important aim of this study is to experimentally verify the seismic performance of full-scale steel frame structures with SCMPs via shaking-table tests capable of applying pulselike ground motion. A literature review of previous research works suggested that near-fault ground motions can amplify the dynamic response of structures and cause more extensive damage compared with far-fault ground motion records. To achieve this goal of studying the effect of near-fault ground motion records on the test structure installed with SCMPs, a nonlinear finite-element (FE) model has been developed for a parametric study in which a set of near-fault ground motion records were used as base excitation to the structure model. The nonlinear dynamic analysis results showed that the test structure exhibited self-centering capability under both design-basis earthquake (DBE) and maximum considered earthquake (MCE) cases. Additionally, the effect of energy dissipation capacity on the test structure’s response is also discussed.
•We propose a new self-centering steel frame with intermediate columns.•Self-centering function of steel frame is achieved by posttensioning steel strands.•The new system improves stiffness of ...larger-span self-centering steel frames.•The new system possesses favorable energy dissipation capacity.•The function of intermediate columns can be restored upon earthquakes.•The new system can protect the main components from being damaged.
A self-centering steel frame system with intermediate columns containing friction dampers (ICSCF) has been proposed in this study to resolve the problem that the interstory drift of the structure may exceed the specified limit in standards when self-centering steel frames (SCF) are applied in multi-rise and high-rise buildings with larger spans, and ICSCF comprises two kinds of friction dampers, intermediate column containing friction dampers (ICFD) and web friction devices (WFD), thus possesses larger energy dissipation capacities under rare earthquakes. An eight-floor prototype of ICSCF was designed and pseudo-dynamic test was conducted on a two-floor testing substructure. Finite element analysis was performed to validate the reliability of testing results. Seismic performance analysis on the overall structure of ICSCF was carried out, which was then compared that of SCF utilizing only beam web friction dampers. The test and the analyses results indicated that the introduction of ICFD has greatly increased the lateral stiffness of the structure and energy dissipating capacity, further extending the application field of self-centering structural systems, making it possible to be applied to larger-span structures.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Summary
In the Y‐type eccentrically braced frame structures, the links as fuses are generally located outside the beams; the links can be easily repairable or replaceable after earthquake without ...obvious damage in the slab and beam. The non‐dissipative member (beams, braces, and columns) in the Y‐type eccentrically braced frames are overestimated designed to ensure adequate plastic deformation of links with dissipating sufficient energy. However, the traditionally code design not only wastes steel but also limits the application of eccentrically braced frames. In this paper, Y‐type eccentrically braced steel frames with high‐strength steel is proposed; links and braces are fabricated with Q345 steel (the nominal yield stress is 345 MPa); the beams and columns are fabricated with high‐strength steel. The usage of high‐strength steel effectively decreases the cross sections of structural members as well as reduces the construction cost. The performance‐based seismic design of eccentrically braced frames was proposed to achieve the ideal failure mode and the same objective. Based on this method, four groups Y‐type eccentrically braced frames of 5‐story, 10‐story, 15‐story, and 20‐story models with ideal failure modes were designed, and each group includes Y‐type eccentrically braced frames with ordinary steel and Y‐type eccentrically braced frames with high‐strength steel. Nonlinear pushover and nonlinear dynamic analyses were performed on all prototypes, and the near‐fault and far‐fault ground motions are considered. The bearing capacity, lateral stiffness, story drift, link rotations, and failure modes were compared. The results indicated that Y‐type eccentrically braced frames with high‐strength steel have a similar bearing capacity to ordinary steel; however, the lateral stiffness of Y‐type eccentrically braced frames with high‐strength steel is smaller. Similar failure modes and story drift distribution of the prototype structures designed using the performance‐based seismic design method are performed under rare earthquake conditions.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
High strength steel frames with curved knee braces (HSSFs-CKBs) are typical seismic resilient structural systems. Previous experimental research showed that an HSSF-CKBs specimen could be readily ...repaired after an earthquake by replacing damaged curved knee braces (CKBs) which serve as energy dissipating devices, as long as high strength steel components stay essentially elastic to shake down post-earthquake residual deformations. To provide a practical tool for engineers in seismic resilience design, this paper developed a performance-based damage-control design framework for low-to-medium rise HSSFs-CKBs. A multi-storey HSSF-CKBs was first interlinked with an equivalent bilinear single-degree-of-freedom (SDOF) system. Then, the seismic input energy demand of the HSSF-CKBs was determined based on the seismic energy balance of the equivalent SDOF system, which was further distributed to different storeys to design structural components. To facilitate the design, a stepwise design procedure was proposed. A three-storey low-rise HSSF-CKBs and a six-storey medium-rise HSSF-CKBs were designed following the procedure. The seismic response of the designed structures was examined by pushover analyses and nonlinear time-history analyses using numerical models verified by shaking table test data. The analysis results showed that the designed structures exhibited the expected behaviour, and the maximum interstorey drifts were controlled below the design target, which verified the effectiveness of the proposed design framework.
•A subassemblage model of high strength steel frames with curved knee braces was developed.•Numerical modelling techniques were developed and verified by shaking table tests.•A performance-based damage-control design framework was proposed.•The adequacy of the proposed design framework was confirmed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This article deals with an experimental program to investigate the in-plane seismic behavior of steel frames with clay brick masonry infills having openings. Six large-scale, single-story, single-bay ...frame specimens were tested under in-plane cyclic loading applied at roof level. The infill panel specimens included masonry infills having central openings of various dimensions. The experimental results indicate that infill panels with and without openings can improve the seismic performance of steel frames and the amount of cumulative dissipated energy of the infill panels with openings, at ultimate state are almost identical. Furthermore, contrary to the literature, the results indicate that infilled frames with openings are not always more ductile than the ones with solid infill. It seems that the ductility of such frames depends on the failure mode of infill piers. This experimental investigation shows that infilled frames with openings experienced pier diagonal tension or toe crushing failure and have smaller ductility factors than those frames with solid infill. Furthermore, a simple analytical method is proposed to estimate the maximum shear capacity of masonry infilled steel frames with window and door openings.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•The beam-through connection equipped with T-type curved knee braces was proposed.•Three full-scale experimental tests were designed and conducted.•Tested specimens exhibited expected cyclic behavior ...and great ductility.•Strength of the connections did not lose entirely after web of knee braces fractured.•Simplified analytical models for the connection were proposed.
This paper introduces beam-through framed connections (BTFCs) with innovative T-type curved knee braces (TCKBs). Beam-through steel frame (BTF) is an emerging system using strip braces as lateral force-resisting components. Even though strip braces can provide high strength and stiffness, they will get slack after yielding since compressive buckling, and dynamic characteristics of the system will be unstable. Innovative T-type curved knee braces are intended to provide stable strength and full energy dissipating capacity. By equipping a BTF with TCKBs, seismic performance of the system can be improved, and architectural space can be released. In order to verify the reasonability of construction details, investigate failure modes and damage sequences, a total of three full-scale specimens with different TCKBs were designed and tested under incremental cyclic loading. Results of tests demonstrated the expected stable hysteretic behaviors, controllable damage sequences and superior ductility. Damages were mainly concentrated on knee braces within 2.0% drift ratio. With subsequent increase of the loading amplitude, plasticity was observed on beam-to-column connection area. Tested knee braces started to be fractured when drift ratio reached 7.0% approximately which was treated as the failure mode. In the final stage of loading, webs of knee braces fractured one after another. After web of four knee braces fractured, specimen could still exhibit partial strength derived from damaged braces and semi-rigid beam-to-column connection which indicated the safety storage after failure mode.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•A new kind of composite columns with a concrete column and an encased angle steel frame was studied in this paper.•Seismic performance of ASFCs was investigated via experiment and simulation ...research.•Based on experiment and simulation results, stress and strain state, plastic hinge length were studied.•Assembly of steel battens, size of steel batten and angle steel bar can characterize the seismic performance of ASFCs.•Finite element model of ASFCs was proposed and verified in this paper.•Expanding study for influence factors of ASFCs was finished via finite element analysis.
Angle steel frame confined concrete columns (ASFCs) are an improved form of steel-jacketed concrete composite columns. An ASFC consists of an concrete column and an inner angle steel frame (ASF). The ASF offers two advantages: confining core concrete and improving seismic performance. The existing studies have been limited on seismic performance of ASFCs. This paper presents experimental and numerical studies on seismic performance of ASFCs. The experimental program included the lateral quasi-static cyclic tests of eight specimens, with the main variables being the axial compression ratio, the section form and the assembly of steel batten. The numerical program included establishment process of numerical models in finite element analysis software (OpenSees), and the expanding analysis on influence factors of ASFCs. The experimental results showed that all ASFCs have high bearing capacity, high ductility and full hysteretic curve. The numerical model could provide reasonably accurate prediction of experimental results. The factor analysis showed that axial compression ratio and steel content of angle steel are two main factors for seismic factors, and the confining effect exerts great influence on dividing axial compression ratio.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This paper presents a novel descent algorithm based on the step-by-step iterative principle, applied to the optimum design of steel frames. The search consists on finding the direction which ...decreases the structural weight most quickly. As the design problem includes discrete variables, the optimum is found by evaluating the structural weight gradient step by step. The step size is controlled in such a way that convergence towards infeasible or suboptimal solutions is avoided. By properly choosing the initial solution, it is possible to increase the efficiency and the convergence speed of the algorithm. Many strategies, for the choice of initial design point, by making use of engineering intuitions or using optimized design obtained by other algorithms are discussed. Furthermore, it is confirmed in this study that the proposed algorithm can be used to improve optimum designs found by metaheuristic algorithms. The optimization results, relative to several weight minimizations problems of benchmark planar steel frames designed according to Load and Resistance Factor Design, American Institute of Steel Construction (LRFD-AISC) specifications, are compared to those obtained by different optimization methods. The comparison proves the efficiency and robustness as well as the prompt of convergence of the proposed descent algorithm developed in this paper.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
