Experimental Study On Compressive Behavior Of Reinforced Brick Wall With Internal Steel Sheet And Polymer Mortar

Masonry structure is widely used in China because of its wide source of materials,low cost and convenient construction.The masonry structure built in the 1950 s and 1960 s has a aging problem,it is unrealistic to rebuild all of them.At the same time,it is not in line with the sustainable development strategy advocated by the country.At this time,the reinforcement of masonry structure become a good choice.The masonry structure reinforcement can not only solve the structural aging problem,but also solve other problems that the structural safety is difficult to guarantee,such as the change of the function,the construction quality does not meet the requirements.In this paper,a new type of masonry structure reinforcement method,the built-in steel plate polymer mortar surface layer reinforcement method,is used to test the axial compression performance.(1)According to the mortar strength grade(M5,M15)and the reinforcement form(orthogonal reinforcement,diagonal reinforcement),six 1/2 scale model walls were designed and fabricated,including 4 reinforcement walls and 2 contrast walls.The axial compression performance tests of the model walls were carried out,by analyzing the difference between the failure mode,bearing capacity and deformation of the reinforced wall and the unreinforced wall,the failure order of each part of the reinforcement wall was determined.It is preliminarily determined that the failure of reinforced wall is caused by the setting of transverse steel plate.(2)Based on the test and finite element analysis,an approximate calculation method for the stiffness of the reinforced wall is proposed.The compressive stiffness calculated by the calculation method and the compressive stiffness calculated by ABAQUS are within 8.7%,which has certain application value in engineering practice.The load sharing method is used to calculate the load shared by each part of the reinforced wall,and the reinforcement effect of the reinforced wall is determined.The test results show that the reinforcement effect of the orthogonal reinforcement wall is better than that of the diagonal reinforcement wall.(3)The finite element analysis of the test wall was carried out by ABAQUS.The failure mechanism of the reinforced wall was further determined by analyzing the stress cloud map of the reinforced wall and combining the experimental phenomena.At the transverse steel plate,stress concentration occurs in the polymer mortar surface layer,and there is a lateral tension zone near the stress concentration position.The tensile failure of this area will cause the polymer mortar surface to outer drum,which will lead to the failure of the reinforcement wall.(4)Through the finite element analysis of the local performance of the reinforced wall,it is found that the internal brick wall under the axial loading has little influence on the strength of the reinforcement surface layer.For this reason,the finite element analysis of the surface layer damage of the reinforcement wall can use the layer partial test pieces.Through the local finite element analysis of the reinforcement surface layer,the calculation method of the average compressive strain of the component when the surface layer is damaged is given.Combined with the approximate calculation method of the wall stiffness,the calculation formula of the bearing capacity of the reinforcement wall is proposed.