Study On Seismic Behavior And Resiliency Of Novel Hybrid Coupled Wall Structures

A novel hybrid coupled wall(HCW)consists of replaceable steel coupling beams(RSCBs)and reinforced concrete(RC)wall piers.Use of the HCW can improve the seismic performance and earthquake resiliency of high-rise buildings.This thesis presents parametric study on coupling ratio(CR)of the HCW system.Performance-based design method is proposed for the HCW,and the influence of HCW on seismic loss(repair cost and repair time)of high-rise buildings is investigated.The major work and associated achievements of the study are summarized as follows:1.Parametric study on CR of HCW is carried out via nonlinear dynamic analysis.The analysis results indicate that:(1)When the CR is overly small,the lateral drift of HCW exceed the limit,and the wall piers may form plastic hinges at middle stories.(2)When the CR is overly large,the HCW cannot achieve the expected yielding mechanism,energy dissipation of coupling beams is limited,and tensile and compressive axial force of wall piers exceed the limit.Based on the parametric study,a method to determine a reasonable CR for HCW is proposed: the lower limit of CR is governed by the elastic lateral drift limit of HCW,and the upper limit of CR is governed by the axial force limit of wall piers.2.Performance-based design method for the HCW is developed.The main work includes: defining the performance objectives of the HCW,determining acceptance criteria based on the fragility research of RSCBs and RC walls,and developing a highefficient preliminary design method based on a parametric study on coupling ratio.Verified by a case study,the preliminary design method can effectively reduce the number of iterations of the performance design.3.Based on the proposed performance-based design method,a HCW is designed for case study.The seismic performance of the HCW is estimated via nonlinear dynamic analysis,and the assessment results indicate that:(1)the HCW has similar elastic performance and yielding mechanism with the conventional RC coupled wall(RCW).Under the maximum considered earthquakes(MCE)and very rare earthquakes(VRE),the lateral inter-story drift of HCW is approximately 30% smaller than that of RCW.(2)When subjected to MCE and VRE,the HCW and the RCW have similar damage states in RC wall piers,which correspond to the concrete cracking and require repair of cracks only.RC coupling beams are severely damaged and difficult to repair,while the RSCBs can be easily repaired by replacing the shear links.The HCW shows enhanced earthquake resiliency relative to the RCW.4.High-rise building structures with HCW or with RCW are designed following the Chinese codes and United States(US)codes.The influence of the HCW on seismic loss of high-rise buildings is assessed based on the FEMA P-58 method.The assessment results indicate that:(1)The major cause of seismic loss of the conventional structure is the damage of RC coupling beams and frames.As the HCW can efficiently control lateral deformation of the structure and the damage to the RSCBs is limited,the repair cost of the structure is reduced by 40% to 50% by use of HCW and repair time is reduced by 45% to 60% under MCE.The use of HCWs has a slightly larger influence on the Chinese buildings than the US buildings.(2)The use of HCWs leads to significantly reduction of seismic loss of drift-sensitive non-structural components,while it has limited influence on seismic loss of acceleration-sensitive non-structural components.