Study On Seismic Behavior Of RC Frame Structure Strengthened With Prestressed Braces

Earthquake movements occurred frequently in China.When earthquake disaster occurred,a large number of RC frame structures in the affected areas were seriously damaged.In view of this phenomenon,based on the idea of performance-based design,this paper uses the application of prestressed support technology in the reinforcement of steel structure buildings for reference,and puts forward a new reinforcement method that applies prestressed support technology to the reinforcement of RC frame structure.In order to verify the effectiveness and superiority of the new reinforcement method,firstly,this paper deduces the calculation formula of the prestressed support area and the initial effective stress based on the seismic design method of deformation(displacement)and verifies its accuracy;secondly,this paper uses yjk software to carry out elastic analysis,static pushover analysis and dynamic elastic-plastic analysis of the RC frame model,and makes statistical calculation.The maximum inter story displacement,the maximum inter story displacement angle and the floor shear force of the model are used to quantitatively evaluate the influence of the factors such as the prestressed support itself and the layout of the support on the seismic performance of the structure under the small,medium and large earthquakes,and to compare with the structural steel support.Finally,the model uses the MSC.MARC The finite element software has carried on the incremental time history analysis(IDA)to the RC frame model calculation example.The results show that the spectrum acceleration Sa(T1)50%collapse,the collapse reserve coefficient CMR and the collapse rate of the model can be used to evaluate quantitatively the influence of the prestressed support itself,the initial effective stress level and the layout of the support on the collapse resistance of the structure under small,medium and large earthquakes.Through the study of this paper,the following conclusions are drawn:(1)under the action of small earthquake,the interlayer parameters of the structure strengthened by prestressed support are optimized,and the structural performance level is improved;different support arrangement forms have little influence on the structural performance level;the reinforcement effect of prestressed support and section steel support is the same.(2)Under the action of moderate earthquake and large earthquake,the interlayer parameters of the structure are optimized and the performance level of the structure is improved after the use of prestressed support;different support arrangements have little impact on the performance level of the structure;the reinforcement effect of prestressed support is better than that of steel support.(3)Under the action of rare earthquake,increasing one degree earthquake and super earthquake,the anti collapse index of the structure strengthened by prestressed support is greatly improved,and the anti collapse ability of the structure is enhanced;different initial effective stress levels have certain influence on the anti collapse performance of the structure,and the optimal initial effective stress is about 600MPa;different support arrangements have different anti collapse performance of the structure The effect of prestressed support is better than that of section steel support.