Seismic behavior of five-story coupled steel plate reinforced concrete composite walls

Abstract

Due to the lack of research background, steel plate reinforced concrete (SPRC) wall piers constructed in the core tubes of super tall buildings in seismic regions have been designed as isolated SPRC walls without considering their interaction (coupling action) provided by the steel link (coupling) beams at floor levels, which may lead to poor material efficiency and underestimated overall performance. Research is urgently needed to examine the seismic performance of multi-pier SPRC walls joined by steel coupling beams at floor levels and provide design suggestions if coupling action is considered. In this research program, a 1/4-scaled two-pier and five-story coupled SPRC wall test model with a coupling ratio of 0.3 was constructed and tested under reversed cyclic lateral loading and constant axial compression. Test results showed stable lateral force versus displacement hysteretic behavior with adequate post-yield deformation ductility, great energy dissipation, and strength retention capacities. The coupling mechanism between SPRC walls and steel coupling beams ensured the expected plasticity and damage distribution pattern. The concrete cracking was insignificant along the entire height of the SPRC wall piers. Steel coupling beams of all floor levels developed considerable inelastic shear deformation and consumed most of the input energy. A numerical simulation of the test model was conducted, and its accuracy was verified against the main experimental results. Parametric analyses were conducted to further investigate the effects of key design parameters on the overall structural response of the coupled SPRC walls. The results indicate that increasing the axial load ratio and steel plate ratio or decreasing the flexure-to-shear ratio of the steel coupling beam can enhance the lateral load carrying capacity. The medium value of 0.15 for axial load ratio, a medium value of 6.6% for steel plate ratio, and a shear-to-flexure ratio of 1.0 for steel coupling beams can result in the best displacement ductility.