Experimental, Numerical and Analytical Studies on the Seismic Response of Steel-Plate Concrete (SC) Composite Shear Walls

Keywords: Earthquake engineering, Steel-concrete composite shear wall, Infill concrete, Steel faceplates, Cyclic test, Bolted-baseplate, connection, In-plane loading, Shear studs, Buckling, Concrete cracking, Concrete crushing, Steel rupture, Energy dissipation, Hysteretic damping, Strain contour, Displacement ductility, Finite element analysis, LS-DYNA, Winfrith model, Parametric study, Design of experiments, Analysis of variance, Empirical equation, Regression model, Effective lateral stiffness, Analytical modeling, Moment-curvature relationship

Abstract: This report presents the results of experimental, numerical, and analytical studies on the in-plane cyclic behavior of rectangular steel-plate concrete (SC) composite shear walls. The SC walls considered in this study were composed of steel faceplates, infill concrete, headed steel studs anchoring the faceplates to the infill, and tie rods connecting the two faceplates through the infill. Four large-size specimens with an aspect ratio of 1.0 were tested under displacement-controlled, in-plane cyclic loading in the laboratory at the University at Buffalo. The design variables considered in the testing program included wall thickness, reinforcement ratio, and slenderness ratio. The walls were identified to be flexure- and flexure-shear critical. The progression of damage in the four walls was identical, namely, cracking and crushing of the infill concrete at the toes of the walls, outward buckling and yielding of the steel faceplates near the base of the wall, and tearing of the faceplates at their junctions with the baseplate. A robust finite element model was developed in LS-DYNA for nonlinear cyclic analysis of the SC walls. The LS-DYNA model was validated using the results of the cyclic tests of the four SC walls. The validated LS-DYNA model was used to conduct a comprehensive parametric study to investigate the effects of wall aspect ratio, reinforcement ratio, wall thickness, and uniaxial concrete compressive strength on the in-plane response of SC walls. Simplified analytical models, suitable for preliminary analysis and design of SC walls, were developed, validated, and implemented in MATLAB. Analytical models were proposed for monotonic and cyclic simulations of the in-plane response of flexure- and flexure-shear-critical SC wall piers. The model for cyclic analysis was developed by modifying the Ibarra-Krawinkler Pinching model. The analytical models were verified using the results of the parametric study and validated using the test data.