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Summary: High‐rise buildings with vertical setbacks are more prone to damage in the event of strong earthquakes. This paper presents an extensive parametric study on the seismic performance of reinforced concrete (RC) frame‐shear wall structures with different setback configurations. Five groups of RC frame‐shear structures with 30 setback configurations were designed. Before conducting extensive non‐linear time history structural analysis, modeling of main lateral force resisting systems including RC column and shear wall was validated using previous test results. By parametric analysis on both horizontal setback ratio and vertical setback ratio, the influences of setback on structural seismic performance in terms of dynamic property, inter‐story drift ratio, acceleration, energy dissipation, and damage condition were comparatively investigated. The overall conclusion is that setbacks caused more than 50% reduction of floor area or positioned at the middle and lower height should be avoided. [ABSTRACT FROM AUTHOR]

Summary: To study the effect of plan irregularity on the collapse performance of reinforced concrete (RC) moment frame structures, three groups of seven‐story RC frame structures with different plan layout, one rectangular and two L‐shaped with different dimensions, were designed and numerically studied. The length‐to‐width ratio, protrusion ratio (length of protruding part divided by the total length), and the length‐to‐width ratio of the protruding part were selected as the study parameters. The fragility curves for the collapse limit state of each structure were generated through incremental dynamic analysis, and the collapse margin ratios of the structures were derived. It is found that the seismic collapse performance of the structure with the rectangular plan is significantly affected by the length‐to‐width ratio, and setting a threshold value of 6 is reasonable. For the L‐shaped structure, the influence of the protrusion ratio and the length‐to‐width ratio of the protruding part on the average collapse resistance capacity is not significant. A larger value increases the collapse resistance under rare earthquake. Effect of setting seismic joint in the L‐shaped structure is also studied, and the results indicate that setting the seismic joint or not hardly influences its seismic collapse performance. [ABSTRACT FROM AUTHOR]

Summary: To address the issue of strength and stiffness degradation of steel slit shear walls (SSSWs) after the occurrence of out‐of‐plane buckling at large lateral deformation, a new type of SSSW made by assembling initially twisted steel plate links is proposed in the present work. Three types of SSSW specimens, with vertical slits, narrow rhomboid openings, and initially twisted steel plate links, respectively, were manufactured and tested under quasi‐static cyclic loading. Test results showed that the SSSW assembled by initially twisted steel plate links had no strength degradation and a nearly constant positive second stiffness throughout the whole loading process with a maximum drift ratio of 6%, whereas the other two SSSW specimens exhibited obvious degradation of strength, stiffness and energy dissipation capacity. The new SSSW also had much smaller residual strength, and its deformation capacity was largely improved. The method to predict the elastic stiffness of the new SSSW was proposed, by which the predicted results agreed well with test results. A user‐defined macromodel was developed to simulate its force‐deformation hysteretic behavior. [ABSTRACT FROM AUTHOR]

Summary: A new type of self‐centering beam‐column joint with installed steel arc plates is proposed in this study. First, mechanical behavior of the self‐centering joint using prestressed steel strands to provide the centering force is theoretically analyzed in detail, followed by experimental validation. New joints with different arc plate parameters are designed and tested under cyclic loading. Test results show that the hysteretic curve of the new joint exhibits typical characteristic of self‐centering capacity. By parametric analysis of five design parameters of the arc plate, it is found that vector height has the greatest influence on the joint's moment‐rotation skeleton curve, which is consistent with experimental findings. A simplified model of the joint is built in OpenSees to simulate its hysteretic behavior, which agrees well with the tested results. To demonstrate the effectiveness of the new joint to improve the seismic performance of the overall structure, a series of nonlinear time history analysis on a steel frame structure with the new joint under earthquakes are conducted, which show that the joint is particularly effective in reducing the residual interstory drift response. [ABSTRACT FROM AUTHOR]

Summary: It has been found from the past earthquakes that the reinforced concrete coupling beams in tall buildings easily suffer severe damage, which are very difficult to be repaired. To solve this problem, a new type of replaceable coupling beam with a combined damper installed in the middle was proposed in this study. The combined damper consists of an I‐shaped steel beam with multiple low‐yield‐point steel webs paralleled to each other and multiple layers of viscoelastic material bonded between multiple steel plates. The design method of the new replaceable coupling beam was introduced first. Cyclic loading tests on the combined damper were conducted to examine its mechanical behavior. To verify the effectiveness of the new replaceable coupling beam in resisting wind and seismic excitations, two high‐rise building structures, one with traditional coupling beams and the other with the proposed replaceable coupling beams, were designed, and the responses of two structures under the wind and the earthquake were compared with the aid of software Perform‐3D. Compared with the structure with traditional coupling beams, both of the seismic performance and the wind resistance capability of the structure with the proposed replaceable coupling beams are improved significantly. [ABSTRACT FROM AUTHOR]