Study On Seismic Performance Of RC Frame Structure With Half-height Infilled Wall Strengthened By CFRP

Frame column plays an important role in reinforced concrete frame structure.It not only bears vertical load,but also resists lateral force caused by earthquake.The seismic performance of frame columns is reduced due to the influence of infilled walls.The seismic damage investigation shows that when the half-height filled wall is built between columns,due to the constraint effect of the wall on the frame column,the free height of the frame column will be shortened,and the lateral stiffness of the column will be increased,so that the unrestrained part will form a weak short column,which is prone to brittle shear failure,thus affecting the collapse resistance of the structure.Therefore,it is of great practical significance to reinforce such short columns.Carbon Fiber Reinforced Polymer（CFRP）has the advantages of light weight,high strength and simple construction,which is widely used in the reinforcement of reinforced concrete frame structures.Appropriate reinforcement of such weak short columns with CFRP can improve the seismic performance of the overall structure,which has great engineering application value.A series of experimental studies on half-height infill wall frame structure strengthened with CFRP are carried out.The main contents and results are as follows :1.Four groups of quasi-static tests of plane frame models were carried out.On the one hand,the comparative tests of frame models with and without infill walls were designed to study the influence of the existence of semi-high infill walls on the overall failure mode of frame structures.On the other hand,the quasi-static test of half-high filled-wall frame structure strengthened with strip and full-pack reinforcement was designed,and the influence of such weak short columns strengthened with CFRP on the overall seismic performance was studied in depth.2.The test results show that:（1）The existence of half-height infill wall can improve the maximum shear capacity of frame structure to a certain extent,but the ductility of the structure is greatly reduced.The failure mode of the column is changed from the long column ’ plastic hinge ’ failure mode of the frame column without infill wall to the short column shear failure of the frame column with half-height infill wall.（2）After strengthening the short column part of the half-height infilled wall frame structure with CFRP,the weak part of the structure is transferred from the short column to the masonry infilled wall.When the infilled wall loses the bearing capacity,the failure of the frame structure is characterized by the ductile failure of the strong column and the weak beam.The failure mode of the plane frame is changed from brittle shear failure to ductile plastic hinge failure,which improves the seismic performance of the whole structure.3.The seismic characteristics of ductility,hysteresis curve,skeleton curve,stiffness degradation curve and energy dissipation of each model are analyzed and compared,and the influence of CFRP reinforcement on the seismic performance of semi-high filled wall frame structure is summarized.The infilled wall can fully play the role of the first seismic line of defense.After the infilled wall is damaged,the reinforced frame column can play a better energy dissipation capacity as a whole.