Antiseismic Performance Analysis Of Infill Wall And First Layer Joints Of Frame Structure

Frame structure are widely used in residential,office buildings,hospitals,schools and other crowded buildings,due to its flexible spatial arrangement.In current code for seismic design of buildings,infill wall is nonstructural component of RC frame structure,and it should use lightweight materials.The earthquake force is completely assigned by the frame,without taking into account the infill wall.In recent years,several big earthquake occurred in southwest of China,many frame structure were seriously damaged because there is no reasonable consideration of infill wall.If the infill wall damaged seriously,with little damage of RC frame,will cause a great loss of property and casualty.We should do more beyond the code to figure out how to fully consider the effects of infill wall on frame structure and how to design the infill wall more reasonable.Frame joints connect the frame beam and column,joints failure will directly lead to connected beam and column failure.And shear failure is brittle failure,should be avoided.However there were many top of columns of first layer and joints of corner column occurred shear failure in Lushan earthquake.We designed different RC frame teaching building with fortification of 6 degree,7 degree(0.1g),7 degree(0.15g),8 degree(0.2g),8 degree(0.3g),9degree(0.4g)seismic intensity,according to Lushan middle school teaching building.The redesigned teaching building use sintered common brick and perforated brick as infill wall material respectively.Nonlinear dynamic time history analysis were made for the structures using specific earthquake of different PGA.Analyzing the infill wall material's influence on the earthquake resistant behavior of RC frame and infill wall.We finished the finite element analysis for simplified single span,double span frame structure and Lushan middle school teaching building to analyze joints failure.Drawing the following conclusions: 1)Recommend the appropriate infill wall material for different fortification degrees RC frame teaching buildings;2)Infill wall have great restraint effect on frame columns,if the column is restrained by infill wall,it will probably have shear damage on the top of column,if not,the joints may occur shear failure;3)The shear failure of corner column may lead to the joint shear failure under the torsion effect;4)Lushan middle school teaching building's torsion effect is caused by non-uniform rigidity,and the uneven distribution of infill wall have great influence on the torsion effect.