Shaking Table Tests And Seismic Performance Assessment Of RC Space Frames With Infilled Masonry Walls

Reinforced concrete(RC)frames with infilled masonry walls are one type of complex composite structures with the mechanical characteristics of both RC frame structures and masonry structures.Existing studies have shown that infilled masonry walls have significant impact on stiffness,bearing capacity and deformation of RC frame structures.It is not reasonable that only period reduction factor is used to consider the influence of infilled masonry walls in the current codes.In previous earthquake events,it has been reported that RC frames with infilled masonry walls have experienced failure modes of strong column-weak beam damage,weak-story damage,short column shear damage and torsion damage caused by infilled masonry walls.Therefore,the study on seismic performance of RC frames with infilled masonry walls will have important practical significance and engineering application value.In this thesis,methods of shaking table test,numerical simulation and theoretical analysis are used to study seismic performance of RC space frames with infilled masonry walls by comparing with RC space bare frames.The main contents of this thesis are summarized as follows:(1)Shaking table tests of a test RC space frame with infilled masonry walls and a test RC space bare frame with 1/2 scale are conducted.Seismic performance of the RC space frame with infilled masonry walls and the RC space bare frame is studied.The influence of infilled masonry walls on seismic performance of the RC space frame is investigated.The whole damage evolution process from initial damage to failure under different earthquake levels are observed.The influences of infilled masonry walls on dynamic characteristic,displacement responses,acceleration responses and failure modes of the RC space frame are investigated.(2)Numerical simulation of RC component tests is performed.Analytical procedures based on Open Sees software are verified.As one of the most important bearing elements,the systematic parametric analysis of seismic performance of RC space columns is performed.The effects of the axial compression ratio and the hoop reinforcement ratio on bearing capacity,ultimate displacement angle and accumulative hysteretic dissipation energy of RC columns under biaxial lateral loads are analyzed.Based on the above analysis,the global macro-finite element models of the test RC space frame with infilled masonry walls and the test RC space bare frame are built using Open Sees.Numerical simulation of shaking table tests of the two test structures and the two corresponding prototype structures is performed in terms of dynamic properties,displacement response and acceleration response.The numerical simulation results are verified by the test results.(3)Three RC space frames with infilled masonry walls and three RC space bare frames are designed according to the current Chinese Codes.The six structures represent low-rise buildings,mid-rise buildings and mid-highrise buildings.Seismic performance analysis of the six buildings is performed by the methods of nonlinear static analysis,i.e.,adaptive pushover analysis and capacity spectrum method,and nonlinear dynamic analysis,i.e.,nonlinear time history analysis and incremental dynamic analysis(IDA).Deterministic assessment of seismic performance of RC space frames with infilled masonry walls is conducted by comparing with the limit displacements corresponding to different damage states(or performance levels)in the current Chinese seismic code.The deterministic influence law of infilled masonry walls on seismic performance of RC space frames is investigated.(4)From the viewpoint of global seismic performance factors,the deterministic assessment of seismic performance of six buildings designed according to the current Chinese codes is performed.By comparing with the results of RC space bare frames,the influence laws of infilled masonry walls on structural global overstrength factor,ductility reduction factor,structural response modification factor and displacement amplification factor of RC space frames are thoroughly investigated.(5)From the viewpoint of probabilistic seismic fragility,the probabilistic assessment of seismic performance of six buildings designed according to the current Chinese codes is performed.By comparing with the results of RC space bare frames,the influence laws of infilled masonry walls on seismic fragilities and the conditional failure probability of RC space frames are systematically analyzed.Though experimental study and numerical analysis,it has been found that the infilled masonry walls increase bearing capacity and stiffness of RC space frames and decrease response of RC space frames.Though studies on global seismic performance factors,it has been found that infilled masonry walls increase structural global overstrength factor,response modification factor and displacement amplification factor of RC space frames.Though studies on seismic fragility,it has been found that infilled masonry walls decrease failure probability of RC space frames.From the deterministic assessment and probabilistic assessment viewpoint,seismic performance factors and probabilistic seismic fragility of RC space frames with infilled masonry walls are studied,and advance the development of Performance-Based Seismic Design theory of RC space frame with infilled masonry walls in Chinese seismic design code.