Search

To achieve seismic resilience, this work investigates a new type of self-centering beam-column joint equipped with arc-shaped steel plate dampers. Six joint specimens, without or with steel plates of different arc radiuses and chord heights, are experimentally studied. Tested specimens exhibit distinct flag-shaped hysteresis loops, indicating stable moment bearing capacity and rotation stiffness, energy dissipation capacity, and self-centering capability. A comprehensive simulation method for the joint is introduced and validated by tests. Then, numerical parametric analysis is carried out to further evaluate the influence of other parameters including plate thickness, steel property, flexibility in connection, and initial prestressing force. [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]

Steel slit shear walls (SSSWs), made by cutting slits in steel plates, are increasingly adopted in seismic design of buildings for energy dissipation. This paper estimates the seismic energy dissipation capacity of SSSWs considering out-of-plane buckling. In the experimental study, three SSSW specimens were designed with different width-thickness ratios and aspect ratios and tested under quasi-static cyclic loading. Test results showed that the width-thickness ratio of the links dominated the occurrence of out-of-plane buckling, which produced pinching in the hysteresis and thus reduced the energy dissipation capacity. Out-of-plane buckling occurred earlier for the links with a larger width-thickness ratio, and vice versa. Refined finite element model was built for the SSSW specimens, and validated by the test results. The concept of average pinching parameter was proposed to quantify the degree of pinching in the hysteresis. Through the parametric analysis, an equation was derived to estimate the average pinching parameter of the SSSWs with different design parameters. A new method for estimating the energy dissipation of the SSSWs considering out-of-plane buckling was proposed, by which the predicted energy dissipation agreed well with the test results. [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]