A multi-modal-analysis-based simplified seismic design method for high-rise frame-steel plate shear wall dual structures

Liu J., Xu L., Li Z.

A new type of steel plate shear wall with self-centering energy dissipation braces (SPSW-SCEDB) was developed. Validation tests of the wall plate and the pre-pressed spring self-centering energy dissipation (PS-SCED) braces were conducted and a single-bay, single-story, 1:3-scale SPSW-SCEDB specimen was designed, fabricated, and tested under cyclic loadings. The results demonstrated that the SPSW-SCEDB exhibited a stable flag-shaped hysteretic response with high initial stiffness, appreciable ductility, and excellent self-centering and energy dissipation capabilities due to the synergistic effects of the wall plate and the PS-SCED braces. The proposed theoretical equations of the compressive force of the wall plate, the ultimate lateral load capacity, and the remaining restoring force of the SPSW-SCEDB were verified. The PS-SCED braces reduced the stiffness degradation of the wall plate and improved the lateral force resistance and the stability of the SPSW-SCEDB system. The wall plate provided more energy dissipation than the PS-SCED braces. The remaining restoring force of the PS-SCED braces should be as small as possible to maximize the energy dissipation of the PS-SCED braces while ensuring that it overcomes the compressive force of the wall plate.

Xu L., Liu J., Li Z.

The present study develops and numerically verifies a new type of earthquake resilient system. The proposed system combines a steel plate shear wall with infill panel connected to beams only and pre-pressed spring self-centering energy dissipation (PS-SCED) braces that provide the self-centering and additional energy dissipation capabilities. The mechanics of this system is explained and the equations governing its stiffness and strength are also presented. A simplified model is proposed to simulate the hysteretic behaviors of the PS-SCED braces, and comparisons with experimental results demonstrate that the proposed model can effectively describe the hysteretic responses of the bracing system. The hysteretic behaviors of the proposed system and the effects of the infill panel and the PS-SCED braces parameters on the system performance under cyclic loadings are analyzed. Results indicate that the proposed system exhibits a flag-shaped hysteretic response with large stiffness, high strength, excellent self-centering and energy dissipation capabilities. The initial stiffness and yield force of the system are well predicted by the governing equations. The energy dissipation capability of the system is mainly affected by the PS-SCED braces, and the system with the self-centering ratio of 0.7 or more can limit the residual deformation to the tolerance for new steel building when the inter-story drift ratio reaches 2%.

Xu L., Liu J., Li Z.

An innovative steel plate shear wall with self-centering energy dissipation braces (SPSW-SCEDB) is proposed, and the mechanical behavior is explained. The system has excellent self-centering capability when the remaining restoring force of the braces is greater than or equal to the compressive force of the wall plate. On the basis of capacity design principles, the distribution equations of bending moment, axial force, and shear force along the beam are developed and then verified by cyclic loading analysis. The effects of the SPSW–SCEDB parameters on the bending moment distribution are investigated using an orthogonal experiment and the sequence of plastic hinge appearance in the beam is also analyzed. Results indicate that to satisfy the strength and residual deformation requirements of the system, the initial force of the brace and the thickness of the wall plate should be sufficiently large, and the brace activation force should be controlled to ensure that the plastic hinge in the beam appears before the in-span plastic hinge. The design procedure of the SPSW-SCEDB is presented.

Ozcelik Y., Clayton P.M.

Steel plate shear walls comprise web plates connected to beams and columns, also referred to as vertical and horizontal boundary elements, respectively. When loaded laterally, web plates induce high flexural and axial demands in the columns due to the development of an inclined tension field. An alternative lateral force-resisting system is proposed in which the steel plate shear wall web plates are attached only to the beams to avoid high flexural demands in the columns resulting from the inclined tension. In this study, beam-connected web plate behavior is characterized using validated finite element models, a simplified strip model is proposed to simulate hysteretic web plate behavior, and equations for the inclination angle of the partial tension field and compressive strength of strips are presented. A comparison between the finite element model, the current strip model from the literature, and the new proposed strip model is provided. Results indicate that the proposed model successfully estimates beam and column demands, base shear capacity, and energy dissipation capacity of the beam-connected web plate for a wide range of web plate aspect ratios and height-to-thickness ratios.

Zirakian T., Zhang J.

Steel plate shear walls (SPSWs) with low yield point (LYP) steel infill plates have been demonstrated in a number of studies to be efficient and promising lateral force-resisting and energy dissipating systems. In fact, use of LYP steel with extremely low yield stress and high elongation capacity compared to the conventional steel enables the employment of infill plates with improved buckling stability, serviceability, and damping characteristics. In contrast to the commonly-used slender and conventional steel plates with relatively low buckling and high yielding capacities, LYP steel plates can have low yielding and high buckling capacities due to the early yielding of the steel material. On this basis, this paper aims at evaluating the structural behavior and performance of SPSWs with unstiffened LYP steel infill plates designed per AISC 341 seismic provisions which typically address SPSWs with slender infill plates. Effects of plate aspect ratio, and combined compressive and shear forces acting on the web plate are also considered in this study. Numerical analysis of the code-designed LYP steel shear wall models demonstrates the efficient strength, stiffness, and cyclic performances of such systems. In addition, the effectiveness of some design requirements specified in AISC 341 code is evaluated based on the behavior of the SPSW components, and design recommendations are provided accordingly. Finally, a modified plate-frame interaction (PFI) method is used to predict and characterize the behavior of SPSW systems with low yielding and relatively high buckling capacities, the effectiveness of which is verified by comparing the predicted response with experimental and numerical results.

Tsai K., Li C., Lee H.

SUMMARY This research investigates the seismic design method and the cyclic inelastic behavior of the bottom column, also called the vertical boundary element (VBE), in steel plate shear walls (SPSWs). This study consists of two parts. This Part 1 paper discusses the anticipated pushover responses for properly designed SPSWs and the possible inelastic responses of the bottom VBE at various levels of inter-story drift. Considering both the tension field action of the infill panel and the sway action of the boundary frame, this study develops a simplified method to compute the flexural and shear demands in the bottom VBE. Based on the superposition method, this approach considers various plastic hinge forming locations at different levels of inter-story drift. One of the key performance-based design objectives is to ensure that the top ends of the bottom VBEs remain elastic when the SPSWs are subjected to the maximum considered earthquake. This paper presents the comprehensive design procedures for the bottom VBE. Furthermore, this study conducted cyclic performance evaluation tests of three full-scale two-story SPSWs at the Taiwan National Center for Research on Earthquake Engineering in 2011 to validate the effectiveness of the proposed design methods. The experimental program, cyclic inelastic responses of the SPSWs and bottom VBEs, and numerical simulations are presented in Part 2. Copyright © 2014 John Wiley & Sons, Ltd.

Kharmale S.B., Ghosh S.

The existing codes and design guidelines for steel plate shear walls (SPSWs) fail to utilise the excellent ductility capacity of SPSW systems to its fullest extent, because these methods do not consider the inelastic displacement demand or ductility demand as their design objective. A performance-based plastic design method for SPSW systems with rigid beam-to-column connections is proposed in this work, which sets a specific ductility demand and a preferred yield mechanism as its performance targets. The effectiveness of the proposed method in achieving these targets is illustrated through sample case studies of four- and eight-storey SPSW systems for varied design scenarios. A comparison with the existing AISC method for the same design scenario shows that the proposed method consistently performs better, in achieving these performance-based targets. The proposed method is modified to account for P-Delta effects, wherever necessary. This modified method is found to be more effective than the original proposal, whenever P-Delta effects are significant.

Guo L., Jia M., Li R., Zhang S.

Thin steel plate shear walls (TSPSWs) are especially concerned due to the economic factor and excellent energy dissipation capacity. TSPSWs commonly define as steel plate with height-to-thickness ratio over 300. The post-buckling capacity, deformability and energy dissipation capacity of TSPSWs are now accepted by structural engineers. This brings about evident economic benefit. This paper presents a finite element analysis of TSPSWs under cyclic loading. The calculated results are compared with experimental results to validate its accuracy. Then based on the finite element model, the influence of height-to-thickness ratio and span-to-height ratio on the hysteretic behavior of TSPSWs is analyzed. Also, the influence of column moment rigidity on the development of tension field is studied. At last, a new simplified Combined Strip Model is introduced which is suitable for the hysteretic analysis of TSPSWs. Based on the Combined Strip Model, a formula for calculating shear strength is proposed, which considers the compression effects of TSPSWs.

Guo L., Li R., Zhang S., Yan G.

Steel plate shear walls (SPSWs) have become more and more popular in recent years because of their potential huge energy dissipation capacity and ductility under lateral loads. Due to their low cost and fast construction, SPSWs have potential application in practice. The finite element software ANSYS applied to the analysis of the hysteretic behavior of SPSWs is described in this paper first. It was found that compressive stress existed in SPSWs and the effects became more evident with decreasing height-to-thickness ratio. This was validated by comparing theoretical and experimental test results. Secondly, based on the analytical results, a modified strip model is proposed. In the modified model, the compressive effects in the panel were taken into account and it was then found that the load-carrying capacity and the energy dissipation capacity agreed well with the already carefully validated experimental results.

Liu S., Warn G.P.

Seismic floor isolation is a method for protecting nonstructural components, equipment and/or valuable building content in traditional fixed base buildings. Seismic floor isolation is achieved by isolating a secondary floor system from the primary structural floor using horizontally flexible elements called isolators. The nonstructural components, equipment and/or valuable building content is placed atop the secondary, isolated, floor system thereby decoupling the isolated component from the floor motion of the primary structural system. Though there is no codified procedure for designing floor isolation systems, the primary difference from traditional base isolation systems is the seismic input and the weight on the isolation system. In this paper results of a numerical study to investigate the performance and sensitivity of floor isolation systems (FISs) designed for the upper levels of multi-story steel plate shear wall frames are presented. The sensitivity of the performance of the FIS to variations in the steel plate shear wall’s web-plate strength and stiffness is investigated. The results of the study show FISs are able to effectively limit, on average, absolute acceleration demands on equipment in the upper levels of multi-story buildings though isolator displacement demands can be large. Further isolator displacement demands and absolute acceleration demands on the equipment are shown to be insensitive to variations in the steel plate shear wall’s material and geometric properties.

Berman J.W.

The AISC Seismic Design Provisions now include capacity design requirements for steel plate shear walls, which consist of thin web plates that infill frames of steel beams, denoted horizontal boundary elements (HBEs), and columns, denoted vertical boundary elements (VBEs). The thin unstiffened web plates are expected to buckle in shear at low load levels and develop tension field action, providing ductility and energy dissipation through tension yielding of the web plate. HBEs are designed for stiffness and strength requirements and are expected to anchor the tension field formation in the web plates. VBEs are designed for yielding of web plates and plastic hinge formation at the ends of the HBEs. This paper assesses the behavior of code designed SPSWs. A series of walls are designed and their behavior is evaluated using nonlinear response history analysis for ground motions representing different hazard levels. It is found that designs meeting current code requirements satisfy maximum interstory drift requirements considering design level earthquakes and have maximum interstory drifts of less than 5% for maximum considered earthquakes. Web plate ductility demands are found to be significantly larger for low rise walls than for high rise walls where higher modes of vibrations impact the response. The percentage of story shear resisted by the web plate relative to the boundary frame is found to be between 60% and 80% and is relatively independent of panel aspect ratio, wall height, or hazard level, but is affected by transitions in plate thickness. Maximum demands in VBEs in design level shaking are found to be considerably less than those found from capacity design for SPSWs with 9 or more stories.

Qu B., Bruneau M.

Consistent with capacity design principles and requirements of ductile behavior, the 2005 AISC and 2001 CSA seismic design codes require that the intermediate horizontal boundary elements HBEs of steel plate shear walls SPSWs be designed to remain essentially elastic with the exception of plastic hinges at their ends when the infill plates fully yield under seismic loading. However, the unexpected failure observed during the tests on a full-scale two-story SPSW suggested that the current design approach does not necessarily lead to an intermediate HBE with the expected performance. This paper presents analytical models for estimating the design forces for intermediate HBEs to reliably achieve capacity design. Those models combine the assumed plastic mechanism with a linear beam model of intermediate HBE considering fully yielded infill panels and are able to prevent in-span plastic hinges. Design forces predicted using the proposed models are compared with those from nonlinear finite element analysis. Good agreement is observed. Finally, the proposed models are also used to explain the observed premature failure of intermediate HBE. DOI: 10.1061/ASCEST.1943-541X.0000167 CE Database subject headings: Shear walls; Steel plates; Earthquake engineering; Seismic design. Author keywords: Shear walls; Steel plates; Capacity; Design; Earthquake engineering; Seismic design.

Ghosh S., Adam F., Das A.

The unstiffened steel plate shear wall (SPSW) system has emerged as a promising lateral load resisting system in recent years. However, seismic code provisions for these systems are still based on elastic force-based design methodologies. Considering the ever-increasing demands of efficient and reliable design procedures, a shift towards performance-based seismic design (PBSD) procedure is proposed in this work. The proposed PBSD procedure for SPSW systems is based on a target inelastic drift and pre-selected yield mechanism. This design procedure is simple, yet it aims at an advanced design criterion. The proposed procedure is tested on a four-story test building with different steel panel aspect ratios for different target drifts under selected strong motion scenarios. The designs are checked under the selected ground motion scenarios through nonlinear response-history analyses. The actual inelastic drift demands are found to be close to the selected target drifts. In addition, the displacement profiles at peak responses are also compared with the selected yield mechanism. Future modifications required for this design procedure for different SPSW configurations are identified based on these test cases.

Chopra A.K., Goel R.K., Chintanapakdee C.

The modal pushover analysis (MPA) procedure, which includes the contributions of all significant modes of vibration, estimates seismic demands much more accurately than current pushover procedures used in structural engineering practice. Outlined in this paper is a modified MPA (MMPA) procedure wherein the response contributions of higher vibration modes are computed by assuming the building to be linearly elastic, thus reducing the computational effort. After outlining such a modified procedure, its accuracy is evaluated for a variety of frame buildings and ground motion ensembles. Although it is not necessarily more accurate than the MPA procedure, the MMPA procedure is an attractive alternative for practical application because it leads to a larger estimate of seismic demands, improving the accuracy of the MPA results in some cases (relative to nonlinear response history analysis) and increasing their conservatism in others. However, such conservatism is unacceptably large for lightly damped systems, with damping significantly less than 5%. Thus the MMPA procedure is not recommended for such systems.

Chopra A.K., Goel R.K.

An Erratum has been published for this article in Earthquake Engng. Struct. Dyn. 2004; 33:1429. Based on structural dynamics theory, the modal pushover analysis (MPA) procedure retains the conceptual simplicity of current procedures with invariant force distribution, now common in structural engineering practice. The MPA procedure for estimating seismic demands is extended to unsymmetric-plan buildings. In the MPA procedure, the seismic demand due to individual terms in the modal expansion of the effective earthquake forces is determined by non-linear static analysis using the inertia force distribution for each mode, which for unsymmetric buildings includes two lateral forces and torque at each floor level. These ‘modal’ demands due to the first few terms of the modal expansion are then combined by the CQC rule to obtain an estimate of the total seismic demand for inelastic systems. When applied to elastic systems, the MPA procedure is equivalent to standard response spectrum analysis (RSA). The MPA estimates of seismic demand for torsionally-stiff and torsionally-flexible unsymmetric systems are shown to be similarly accurate as they are for the symmetric building; however, the results deteriorate for a torsionally-similarly-stiff unsymmetric-plan system and the ground motion considered because (a) elastic modes are strongly coupled, and (b) roof displacement is underestimated by the CQC modal combination rule (which would also limit accuracy of RSA for linearly elastic systems). Copyright © 2004 John Wiley & Sons, Ltd.

Yang S., Jin S., Li M.

Yu J., Lu W., Wang X., Feng X., Shi W., Li B.

Chen C., Zhong W., Duan S., Tan Z., Zheng Y.

Zou X., Gong M., Zuo Z.

A novel and efficient method based on shear models considering hysteretic characteristics is proposed for predicting structural seismic responses. This method simplifies an actual building by representing it as a lumped mass shear model, with a set of tunable parameters allocated to the interstory restoring force model of each floor. The shear model is calibrated by matching the cyclic interstory pushover curves between the equivalent inelastic spring of each floor and the refined beam–column element model using a metaheuristic optimization algorithm. The novelty of the proposed method lies in its consideration of both cyclic envelopes and hysteretic characteristics (stiffness and strength deterioration and pinching behavior) and its automatic parameter calibration. Validation of the parameter calibration procedure is performed by comparing it with empirical methods via the application on three lateral load tests of reinforced concrete (RC) columns that exhibit varying degrees of hysteretic degradation. The efficiency and accuracy of the proposed method are confirmed through four illustrative examples, including the seismic response predictions of a bare RC frame, two steel frames, and an infilled wall RC frame. Despite the relatively large errors in the acceleration response predictions, the results demonstrate that the proposed method can accurately and efficiently predict the displacement and velocity responses.

Pan Z., Si D., Jiang S., Huang Z., Meng S.

Composite shear walls are usually employed at the bottom of super high-rise structures to resist large axial forces, bending moments, and shear forces. A lot of investigations have been carried out on composite shear walls, but there are fewer comparative studies on composite shear walls with different steel layouts. In this paper, low cyclic horizontal loading tests were carried out on conventional reinforcement concrete shear walls and composite shear walls with different steel layouts (H-section steel in boundary members and the steel plate in the shear wall web, H-section steel in boundary members and the slotted steel plate in the shear wall web, evenly arranged H-shaped steel in the wall). Comparative analyses of load-carrying capacity, failure modes, and seismic performance were conducted. The effects of different steel layouts on the seismic performance of composite shear walls were investigated. Based on the tests, the finite element method is used to further analyze the influence of the shear span ratio of the shear wall and the opening rate of the built-in slotted steel plate.

Souhaibou A., Li L.

The aim of this study is to propose a comparison between wind and seismic loads on a multi-story reinforced concrete (RC) building. The investigation focuses on lateral displacements and story drifts of a 6-story RC structure, which are determined manually using the base shear method and with the aid of the ETABS software tool. The study considers a linearity of the structure and uses the Chinese building design code for lateral displacement analysis. The base shear method is a simplified method that only considers one degree of freedom for each story, neglecting the non-linearity of the structures. However, the Chinese building code permits its use when considering the consistent vertical distribution of the building's mass and stiffness, which leads to shear deformation prevailing during seismic and wind reactions. The lateral displacements under wind and seismic loads are estimated, and the story drift limitation criteria of the Chinese building design code are assessed. Both the base shear method and ETABS's story drift computation (story drift 1/550) meet the design code criteria. This indicates that the base shear technique approach of RC frame structures can reasonably predict the tale drift on each story, despite relying heavily on simplifications. To compare the outcomes from the ETABS program to the internal forces under seismic and wind load activities, the story displacements and drifts are computed. The results show little discrepancy between the base shear method and ETABS software. Hence, the base shear approach can be utilized when there is no irregularity, and the building height is less than 40 m. Overall, the findings of this study indicate that the base shear method can provide a good approximation for the lateral displacements and story drifts of multi-story RC constructions under wind and seismic loads, provided that the Chinese building code criteria are met. The study highlights the importance of using appropriate design codes and tools in ensuring the safety and reliability of structures. Further research can explore the applicability of similar simplified methods in more complex and irregular structures, and the development of more accurate and efficient design tools.

Zhang H., Zhou X., Ke K., Yam M.C., He X., Li H.

This paper explored the seismic behaviour of self-centring hybrid-steel-frame (SC-HSF) employing energy dissipation sequences and the corresponding inelastic seismic demand model. The SC-HSF employing energy dissipation sequences was composed of the self-centring main frame (SCMF) and energy dissipation bays (EDBs). Two prototype structures were designed and developed using modelling techniques validated by experimental data. Nonlinear cyclic pushover analyses and nonlinear dynamic analyses were conducted to examine the seismic behaviour of the prototype structures. The seismic response of prototype structures including peak interstorey drifts and post-earthquake residual interstorey drifts were examined in detail. After verifying the promise of the SC-HSF structures, the energy factor for quantifying the inelastic seismic demand was developed by nonlinear spectral analyses based on the equivalent single-degree-of-freedom (SDOF) systems assigned with the structural hysteretic model. The effects of the structural hysteretic parameters on the mean and probabilistic features of the energy factors were discussed in detail. In addition, the lognormal distribution was selected to develop a probabilistic spectral seismic demand model based on a comparative study, and the prediction equations were developed to simulate the probabilistic features of the energy factors. Finally, the probabilistic spectral seismic demand model was used for evaluating the behaviour of the prototype structures, and the sufficiency of the model was justified. • Self-centring hybrid-steel-frame employing energy dissipation sequences was proposed. • The seismic behavior of the novel structure was examined. • A probabilistic spectral seismic demand model was developed.

Qiu C., Cheng L., Du X.

By employing two or more types of braces, hybrid braced frames (HBFs) combine the merits of the adopted braces and offsets their drawbacks. However, the corresponding seismic design method is still under development. To this end, this paper develops a performance-based seismic design (PBSD) method, based on the performance-based plastic design (PBPD) method. In current work, the buckling-restrained braces (BRBs) and shape memory alloy braces (SMABs) are introduced, because they are known for high energy-dissipating capacity and excellent self-centering capability, respectively. The participation extent of BRBs and SMABs is controlled by the stiffness contribution factor. The equations governing the design results are derived and the step-by-step procedure is detailed. A six-story benchmark frame is selected to demonstrate the design method. The designed HBF is subjected to a suite of earthquake ground motions, and the mean demands of seismic responses are compared against performance targets. It indicates that the HBF designed by the design method can well meet the design targets. A parametric analysis is conducted to reveal the effect of changing the stiffness contribution factor on the seismic demands of the HBF. This study validates the proposed design method for HBF, and it may also shed light to the PBSD method of the structures equipped with the other types of displacement-dependent damping braces. • It proposes a seismic design method for hybrid braced frames. • The hybrid braced frames can meet the requirements of multiple EDPs simultaneously. • The optimal value of stiffness contrition factor of BRB system to the hybrid system is 0.7.

Mirlohi J., Memarzadeh P., Behnamfar F., Bayat M.

In the concept of conventional structural design, the general assumption is that the structure is fixed at its base, while the fact is that the supporting soil medium allows for some general motions of the foundation due to its flexibility. Regardless of stiffness of structure’s frames, this phenomenon results in a subsequent increase in natural period of the system and alters the overall expected response. Moreover, considering soil–structure interaction (SSI) in dynamic analysis of a building structure may result in producing an additional motion of the structure due to rocking motion of the building. The main purpose of the current study is to explain how the mechanism of the effect of rocking motion on the behavior of a steel plate shear wall (SPSW) structure. In this order, the SSI phenomenon is studied and explained in a typical mid-rise steel plate shear wall frame resting on shallow foundation. The SSI effects on the inelastic responses of such a frame due to El Centro 1940 earthquake were examined in detail using a direct method, and also, the results were compared to those for the fixed base frame. Then, a procedure is presented to clarify how SPSW behavior could be influenced by rocking component. Here, two site conditions were considered (typical stiff and soft soil deposits). The results indicated that the SSI greatly affects the seismic performance of the SPSW structure in terms of the seismic story shear forces, displacements and story drifts.

Bai J., Huang J., Chen H., Xu L., Wang Y., Jin S.

As a new type of lateral force resisting member, steel plate shear walls (SPSWs) have the advantages of excellent energy dissipation, high lateral stiffness, and ductility. Owing to the lack of loading characteristics of an actual earthquake in the existing loading protocol of SPSWs, the interpretation of the seismic performance of SPSWs is still challenging. A set of standardized loading protocols for SPSWs under far-field and near-fault earthquakes were proposed, to replicate the real loading histories in severe earthquakes. By using the rainflow counting method, the seismic parameters (such as damage cycle, interstory drift range, and residual interstory drift) from four frame–SPSW structures subjected to a series of representative ground motions, were analyzed to develop the loading protocols. Moreover, the rationality of the proposed loading protocols was discussed and verified by demonstrating the cumulative distribution function and energy dissipation of these protocols. It is well illustrated that the proposed protocols can truly simulate the loading history of members and accurately reflect the seismic damage demands in the inelastic stage.

Fang C., Wang W., Qiu C., Hu S., MacRae G.A., Eatherton M.R.

Steel structures have long been recognized as excellent earthquake-resistant systems. However, this viewpoint wavered after the 1994 Northridge and 1995 Kobe earthquakes, when thousands of steel buildings experienced local or global damage making them difficult, if not impossible, to repair. To avoid the inconvenience and costs associated with such damage, significant research has been conducted on approaches that enhance structural resilience. This paper summarizes some of the recent technological advances in the field of seismic resilient steel structures, covering diverse aspects including emerging smart materials, novel members, and innovative design of structural systems. Challenges arising from the incorporation of these new design philosophies are also described and areas for further development are identified. Performance-based design approaches for seismic resilient steel structures are touched upon, and some practical applications that have emerged over the last decade are presented. Instead of giving an exhaustive compilation of all the relevant studies, this paper highlights the authors' unique reflections emphasizing current issues and future needs related to steel buildings. This paper should not only benefit professionals and researchers who have been working in this area for a long time, but it also enlightens a wider audience wishing to become acquainted with the state of the art related to this exciting topic. • Recent technological advances in seismic resilient steel structures are critically reviewed. • Emerging smart materials, members and structural systems are covered. • Challenges of new design philosophies are described with further research needs identified. • Performance-based design for seismic resilient steel structures is touched upon. • Practical applications that have emerged over the last decade are presented.

Jiang Z., Yan T., Zhang A., Su L., Shen C.

Based on the idea of earthquake-resilience, this paper proposes a new special steel frame with stiffened double steel plate shear wall (SSF-SDSPSW). Compared with traditional steel frame, the special steel frame (SSF) adopts the link beams to dissipate energy and protect columns and beams during earthquake. Therefore, the function of SSF-SDSPSW can be repaired by replacing damaged local parts after earthquake. In addition, stiffened double steel plate shear wall (SDSPSW) has good seismic behavior and fast construction speed. To study the seismic behavior and repairable function of SSF-SDSPSW, one basic specimen and two repaired specimens were subjected to the low-cycle reciprocating loading test and ultimate state loading test in this paper. The experiment results indicated that the buckling of steel faceplates and overall instability of the SDSPSW were main failure modes of the SDSPSW. The SDSPSW cooperated well with the special steel frame. The main members such as frame columns and beams of basic specimen remained elastic basically during loading. The peak load of repaired specimen was higher than 87% of basic specimen, which proved the feasibility of post-earthquake repairability. The displacement ductility coefficient of the SSF-SDSPSW was larger than 3.67, indicating the structure had good deformation performance. The error of peak loads between finite element analysis and experiment was only 3.2%, demonstrating that the finite element analysis can predict the peak load precisely. In addition, parameters analysis indicated that the rational relationship between link beams, SDSPSW and columns were conducive to the damage control of SSF-SDSPSW. • A new special steel frame with stiffened double steel plate shear wall was proposed. • Three specimens were subjected to the low-cycle reciprocating loading test. • Seismic performance and post-earthquake reparability of the structure were studied. • The proposed structure had two seismic defense line, suitable for earthquake area. • Finite element analysis can predict the peak load of SSF-SDSPSW precisely.

Fu H., Bian S., Li O., Macey J., Iglesias A., Chaudhry E., You L., Zhang J.J.

In this paper, we present a new modelling method to create 3D models. First, characteristic cross section curves are generated and approximated by generalized elliptic curves. Then, a vector-valued sixth-order partial differential equation is proposed, and its closed form solution is derived to create PDE surface patches from cross section curves where two adjacent PDE-surface patches are automatically stitched together. With the approach presented in this paper, C2 continuity between adjacent surface patches is well-maintained. Since surface creation of the model is transformed into the generation of cross sectional curves and few undetermined constants are required to describe cross sectional curves accurately, the proposed approach can save manual operations, reduce information storage, and generate 3D models quickly.

Bai J., Zhang J., Jin S., Wang Y.

The steel plate shear wall (SPSW)-frame structure is a high-performance lateral force-resisting system, which has been widely utilized in high-rise buildings, especially in seismic-prone regions. The complexity of SPSW modeling and the interaction between SPSWs and frame, make it very time-consuming and low-efficiency for the performance-based seismic performance evaluation of SPSW-frame systems. This paper developed a simplified computational analytical model of SPSW-frame system based on the lateral deformation characteristics of the system. The simplified flexure-shear (F-S) model was composed of the flexure springs and shear springs, to respectively simulate the behaviors of SPSW and frame. Also, the P -delta column was incorporated into the simplified model to account for the P -delta effect. The material parameters of the flexure spring and shear spring were calibrated by the response spectrum method. By employing the PEER full probability theory, the seismic performance evaluation of two 7- and 15-story SPSW-frame structures were carried out using the simplified F-S model and refined finite element method (FEM). The analytical results demonstrated that the simplified flexure-shear model can achieve nearly the same performance parameters, compared with the refined FEM. Furthermore, the repair cost and repair time of the SPSW-frame structures mainly came from the non-structural components.

Jin S., Du H., Bai J.

The near-fault ground motion records may impose high seismic energy input to the building structures. The steel plate shear walls (SPSW) are one of the robust and efficient lateral-force resisting and energy-dissipating components and SPSWs are increasingly equipped in steel moment frame to form a dual structural system. A modified type of buckling-restrained SPSW with inclined slots has been proposed and applied in the steel frame. This paper presents the seismic performance of steel frame-SPSW system subjected to near-fault ground motions. Four multi-story (5-, 10-, 15- and 20-story) steel frame-SPSW structures were selected and designed. The accuracy of the SPSW models' predictions was assessed using previous experimental results. Nonlinear time-history analysis assuming two groups of 15 near-fault ground motions and 15 far-fault ground motions was used to predict the structures' interstory drift ratios, floor accelerations, residual interstory drift ratios and drift concentration factor. Incremental dynamic analysis was used to predict collapse probabilities using the same groups of ground motions. The analytical results can provide significant insights to the seismic behavior of steel frame-SPSW structures when subjected to near-fault ground motions. • A novel dual steel frame – slotted SPSW structure system was proposed. • The simple model of the slotted SPSW was developed. • Four multi-story steel frame-SPSW structures were analyzed under near-fault ground motions. • Seismic performance and fragility curves of steel frame-SPSW structures were obtained.