Experimental Research On Seismic Resistance Behavior Of Brick Wall Reinforced By Dry-connected Steel Plate Rigid Frame

The masonry structure is one of the common forms of the building structures.It is widely used in all kinds of projects because of its common materials and low cost.However,with the development of the society,the shortcomings of masonry materials have gradually emerged.In recent years,the statistics of earthquake disasters also show that the masonry structure has poor seismic performance.When the earthquake comes,the masonry structure is prone to damage or collapse,which will bring casualties and property losses.Therefore,it is of great significance to strengthen the masonry structure.Among all kinds of masonry reinforcement methods,steel plate belt reinforcement has the advantages of convenient construction and strong reversibility.Based on the reinforcement method of steel plate belt,this paper puts forward the reinforcement method of dry-connected steel plate rigid frame.The main method is to weld the steel plate frame and arrange it on both sides of the existing brick wall.The steel plate frame and the brick wall are only connected by the pull bolt,which belongs to the dry connection.In order to understand the seismic performance of brick wall reinforced by dry-connected steel plate rigid frame,this paper carries out an experimental study and corresponding analysis.One unreinforced brick wall and four brick walls reinforced by dry-connected steel plate rigid frame and one brick wall strengthened with steel strips were tested under quasi-static loading.In this paper,the thickness of the steel plate,the level of the vertical load and the reinforcement form are taken as the research parameters.The failure characteristics,stress characteristics and strain development process of the steel plate are obtained through the tests.The main seismic performance of the reinforced brick wall is analyzed from the aspects of hysteresis curve,skeleton curve,bearing capacity and displacement ductility,stiffness degradation curve and energy dissipation capacity.The test results show that the crack load,yield load,peak load and ductility coefficient increase by 41%～88%,29%～71%,43%～78%and 117%～250%,respectively,compared with the normal brick wall without reinforcement.After reinforcement,the hysteresis curve of the brick wall becomes fuller,the stiffness degradation rate slows down and the accumulated energy consumption increases.Using drytype steel plate frame to strengthen the existing brick wall can effectively improve the shear capacity of the brick wall,increase the deformation capacity of the wall,and significantly improve the hysteretic energy consumption and other important seismic indicators,showing a better seismic performance.Then,based on the existing test results,this paper uses ABAQUS to conduct finite element analysis and adopts the integral modeling method to establish the finite element model of brick wall reinforced by dry-connected steel plate rigid frame,and compares it with the test results to verify the rationality of the model.Then,based on the modeling method,the extended analysis was carried out,and the main research parameters were as follows: the level of vertical load,the distance between the tension bolts,and the compressive strength of the masonry.The results show that the initial stiffness and the peak shear bearing capacity of the reinforced brick wall can be increased slightly by increasing the vertical load level.The increase of the distance between the bolts will make the steel plate more prone to buckling,and reduce the peak shear capacity of the reinforced brick wall to some extent.The method can greatly increase the peak shear capacity of masonry walls of different strength grades,and the reinforcement effect is better when the compressive strength of masonry is low.Finally,based on the test results,the skeleton curve model and stiffness degradation law of brick wall reinforced by dry-connected steel plate rigid frame were proposed by piecewise fitting method,and the corresponding restoring force model was established.In addition,based on the research results of related scholars,the design method of brick wall reinforced by dryconnected steel plate rigid frame is preliminarily presented.