Numerical Simulation For Seismic Performance Of Flexible Connection Masonry-infilled RC Frames

The masonry-infilled RC frames are used widely in buildings,for their economical inherent and flexibility in layout.However,many earthquake damages indicated that the structure was severely destroyed because of rigid connection between the infill wall and frame,and ignored the influence of the infill wall on the overall rigidity of frame structure in structural design.In order to alleviate the above problems,our country's “Code for seismic design of buildings”(GB50011-2010)gives recommendations for the use of disconnection or flexible connections between infill wall and frames,but doesn't give specific measures.In order to study the seismic performance of the masonry-infilled RC frame structure with flexible connection,Chen Guowu(2017)and Luo Mingkang(2018)tested the seismic performance of autoclaved aerated concrete block infill wall frame structures with basalt fiber grids(BFG).This paper based on the experiment studys the dynamic performance of the flexible connection masonry-infilled RC frame structures by ABAQUS.The main work is as follows:(1)Based on the ABAQUS finite element software,establish the finite element model of flexible connection infilled RC frame structures with BFG.Analyzing the constitutive relationship of the masonry with BFG,and giving the tensile and compressive constitutive equation according to the experiment;Establishing the infill wall finite element model by the simplified separation method,and simulating the interface between the block and mortar by the surface-based viscous behavior in ABAQUS.Simulating the flexible connector used in the test by the nonlinear spring unit in ABAQUS,and giving the spring model rigidity in combination with the force form and material properties of the connector.(2)Analyze the finite element model and verify their rationality.Analuzing the inplane and out-of-plane mechanical properties of the established finite element model,and comparing the failure mode,stress,deformation,damage,stiffness and bearing capacity of the model with the test results to verify their rationality.(3)Compare the analysis results of the different finite element model with flexible,and select the most reasonable spring stiffness.Compare the failure mode,stiffness and bearing capacity of the infilled frame structure with the flexible connection such as the tongue plate,L-shaped plate and plywood.Select the spring stiffness from most reasonable simulation result,and apply the selected spring to the subsequent research on the dynamic performance of the flexible connection infilled frame structure.(4)Perform time-history analysis on the different infill wall frame structure finite element model,and study its seismic performance.Establish the finite element model of the infilled frame structure in the form of pure frame,rigid and flexible connection of the infilled frame,filled wall uniform layout,and the bottom weak layer.Input the seismic wave with 0.2g and 0.4g acceleration amplitudes to the finite element models of different types,and compare with the base reaction force,floor acceleration amplification factor,floor displacement,floor displacement angle,structural stress and damage of the finite element model,and then study the dynamic performance of the flexible connection infilled frame structure.