Cyclic Behavior And Design Methods Of Corrugated Double-skin Composite Shear Walls

Double-skin composite(DSC)shear walls had been widely employed in high-to super high-rise buildings as axial and lateral load-resisting systems with high efficiency.For traditional DSC shear walls,elastic buckling was prone to occur on flat faceplates due to their insufficient out-of-plane bending stiffness,thereby leading to insufficient utilization of faceplate strength,and strength and ductility degradation of the system.Therefore,a large number of connectors had to be employed to prevent the flat faceplate from elastic buckling,while it would result in a high material and labor cost.Corrugated faceplate provides much higher out-of-plane bending stiffness and critical buckling stress than flat faceplate.Therefore,corrugated faceplate would be a good choice for DSC shear walls to overcome their shortcomings caused by faceplate buckling,and potentially achieve better seismic performance.However,there remains a significant gap on seismic performance and design methods of the innovative corrugated DSC shear walls and their coupled wall systems.In this paper,seismic performance,failure mechanism,and design methods of the corrugated DSC shear walls and their coupled wall systems were theoretically,experimentally,and numerically studied.Main research contents and conclusions are summarized as follows:(1)Formulations for calculating compressive and shear critical local buckling stress of corrugated faceplates were derivated based on the energy method.An interactive formulation for predicting critical buckling stress of corrugated faceplates under combined compression and shear was then obtained.Finite element(FE)analyses were conducted on the elastic buckling behavior of corrugated faceplates in corrugated DSC shear walls.The proposed formulations were compared to the FE simulation results with a reasonable prediction of compressive and shear critical buckling stress of corrugated faceplates,and critical buckling stress of corrugated faceplates under combined compression and shear.Recommendations for corrugation shape and bolt spacing design were provided.(2)Cyclic tests were conducted on corrugated DSC shear wall specimens to study the effects of aspect ratio and column base strengthening method on wall seismic performance,failure mechanism,and load-carrying mechanism.A column base strengthening method,that attaching a reinforcing sheath to the column base,was proposed.Test results indicated that the hysteresis loops of all specimens were relatively full,and all specimens showed moderate stiffness and strength degradation.All specimens achieved a drift ratio capacity exceeding 1.9%,a ductility ratio greater than3.2,and an equivalent viscous damping ratio over 0.3,implying a good seismic performance.The proposed column base reinforcing sheath contributed to delay tube buckling and improve deformation capacity of the slender DSC shear wall without notably increasing lateral stiffness and strength.(3)Detailed FE models of corrugated DSC shear walls were setup using ABAQUS.FE parametric studies were conducted to examine the effects of wall aspect ratio,axial load ratio,corrugation profile of corrugated faceplate,thickness of corrugated faceplate and boundary tube,and column base strengthening method on wall lateral response using ABAQUS.Following the plane section assumption and superposition principle,formulations were derivated for calculating the flexural strength and shear strength of corrugated DSC shear walls,and compared to test and FE simulation results.The formulations could provide a reasonable prediction of the wall strength.A hysteretic model for predicting the cyclic response of corrugated DSC shear walls was proposed and validated with the hysteresis loops obtained from cyclic tests.(4)Cyclic tests were conducted on corrugated DSC coupled shear wall specimens to study the effects of coupling ratio on wall seismic performance,failure mechanism,and load-carrying mechanism.Test results indicated that the hysteresis loops of the specimens were relatively full.The corrugated DSC coupled shear wall specimens could achieve a drift ratio capacity of 2.39%,a ductility ratio of 5.2,and an equivalent viscous damping ratio of 0.3-0.39,implying a good seismic performance.The lateral stiffness and load-carrying capacity of corrugated DSC coupled shear walls could be effectively improved by increasing coupling ratio,thereby leading to economy and efficiency in structural design.However,increasing coupling ratio would also cause that the neutral axes of wall piers cross-section move toward to the inner boundary columns,thereby potentially increasing the longitudinal stress in exterior boundary columns.(5)Both detailed and simplified FE models of corrugated DSC coupled shear walls were setup using ABAQUS.FE parametric studies were conducted on simplified FE models to examine the effects of storey,lateral load pattern,wall pier axial load ratio,wall pier and coupling beam cross-section properties,and coupling ratio on wall lateral response,failure mechanism,and load-carrying mechanism.According to the forming sequence of plasticity zone and the stress state of wall piers and coupling beams,an expected failure mechanism,that is,as all coupling beams achieved their ultimate strength,the wall piers developed into plastic state while did not reach their ultimate strength,were proposed.The failure mechanism of corrugated DSC coupled shear walls would change along with the change of storey,wall pier axial load ratio,wall pier and coupling beam cross-section properties,et al.(6)The stress state of wall piers and coupling beams in corrugated DSC coupled shear walls were theoretically analyzed using the continuum medium method.A method for predicting the flexural strength demand of wall piers,when all coupling beams achieved their ultimate strength,were proposed.Following the plane section assumption,formulations for predicting the ultimate flexural strength of wall piers were derived,and a formulation for predicting the ultimate flexural strength of coupled shear wall systems was then obtained.A criterion for predicting failure mechanism of coupled shear walls,and a strength design method for coupled shear walls achieving the expected failure mechanism,were proposed.The formulations and the strength design method were validated using test and FE simulation results.