Research On Seismic Performance Affected By Fortification Intensity And Reinforced Methods Of Existing RC Frame Structure

The fifth generation of national standard "China seismic parameters zoning map"(GB18306-2015)was officially implemented on June 1,2016.After the revision,the unfortified areas are cancelled,and the peak acceleration of ground motion is defined to the towns and villages and improved to some extent.With the increasing standard of earthquake resistance in China,a large number of existing RC frame structures are seriously deficient in seismic resistance and cannot meet the requirements of the new codes.It is necessary to make a full study of its seismic performance and to meet the requirements of the new code after seismic reinforcement.Therefore,it is necessary and meaningful to study the effect of intensity enhancement on seismic behavior of existing RC frame structures and its reinforcement methods.The existing RC frame structures in Harbin administrative area were taken as the research object.The effects of 6 degrees(0.05g)to 7 degrees(0.10g),7 degrees(0.15g)and 8 degrees(0.20g)on seismic behavior of existing RC frame structures and their strengthening methods were studied,based on the structural design software and nonlinear analysis software of complex structure,PKPM2010,Chinese academy of building sciences research platform.The following aspects were studied:(1)The influence of the fortification intensity increased from 6 degrees(0.05g),respectively,to 7 degrees(0.10g),7(0.15g),8 degrees(0.20g)on seismic performance of existing RC frame structures such as axial compression ratio,shear weight ratio,just weight ratio,period ratio,displacement ratio,maximal interlaminar displacement angle and reinforcement etc is analyzed,based on structure design software of PKPM2010 and under the frequent earthquake.(2)Ten ground motion records were selected by SAUSAGE nonlinear finite element analysis software.And the incremental dynamic analysis is used as nonlinear time history analysis method.Based on IDA analysis of existing RC frame structures,IDA curves and performance points of existing RC frame structures are obtained.And The seismic performance of existing RC frame structures with the intensity increased from 6(0.05g)to 8(0.20g)was evaluated.(3)The strengthening requirements and methods of existing RC frame structures with the intensity increasing from 6(0.05g)to 8(0.20g)are expounded,and the 10-storey RC frame structures with the intensity increasing from 6(0.05g)to 8(0.20g)are analyzed.According to the selection principle of reinforcement methods,two kinds of reinforcement methods,reinforced concrete sleeve and additional seismic wall or wing wall,are selected for comparative analysis.After analysis,it is concluded that the strengthening method of adding seismic wall or wing wall is better than that of reinforced concrete sleeve.The seismic performance of existing RC frame structures reinforced with additional seismic wall or wing wall was analyzed by using SAUSAGE software as a platform under the severe earthquake.The results show that the reinforced structure is reliable.