Experimental Investigation On Compressive Behavior And Failure Mechanism Of Brick Masonry In Association With Vertical Steel Strips

Brick masonry structure is still widely distributed in China.Due to the problems of insufficient strength and poor seismic performance,brick masonry structure has been a research hotspot in the field of civil engineering reinforcement.Brick masonry in association with vertical steel strips(through bolt connection)is an effective method,and has the advantages of convenient construction,low price,good reversibility and so on.In addition,the application of pre-compression stress in the vertical steel strip can also make the steel strip participate in the work in advance.For a long time,scholars from all over the world have focused on the overall macro analysis of steel plate belt brick masonry composite members,but only given the range of technical parameters such as load or deformation,or put forward a simplified bearing capacity prediction model.In order to better grasp the cooperative performance between steel strip and brick masonry,especially the vertical steel strip prone to local buckling.In this paper,the vertical steel strip is taken as the research focus,and the compressive performance and failure mechanism of the cooperative work between the vertical steel strip and brick masonry are studied in detail.In this paper,thickness,width and pre-compression stress of steel strip were taken as the research parameters.The axial compression performance of one unreinforced brick masonry specimen and nine vertical steel strip brick masonry specimens were designed and completed.The failure characteristics,cracking load,peak load and strain in steel strip were collected and analyzed.The test results showed that the peak load of the steel strip brick masonry specimens was increased by 17%~38% compared with that of the brick masonry specimen;the cracking load of the specimens without pre-compression stress changed little,and the cracking load of the specimens with pre-compression stress increases by 8%~33%;the vertical steel strip reaches the peak bearing capacity first,and then the vertical steel strip reaches the peak bearing capacity The initial deformation and final deformation of vertical steel strip increased with the increase of pre-compression stress.On the basis of experimental research,ABAQUS finite element software was used to establish the finite element analysis model of vertical steel plate belt brick masonry.Through the load displacement curve obtained by comparative test and numerical simulation,the rationality of the finite element analysis model was verified.On the basis of expanding the experimental research parameters,the bolt restraint strength parameters were added.The results showed that the larger the pre-compression stress in the vertical steel strip,the earlier the stiffness degradation time and the lower the peak load;under the same pre-compression stress condition,the increase of the section width of the vertical steel strip could improve the stiffness and peak load of the test piece;under the same condition,the stronger the restraint effect of the bolt end of the vertical steel strip was,the greater the bearing capacity of the vertical steel strip would be.In addition,based on the test and finite element research results,the compression failure of vertical steel strip brick masonry was divided into elastic stage(stage I),crack stage(stage II),steel strip strengthening stage(stage III)and failure stage(stage IV),and the calculation method of compression bearing capacity of this reinforcement method was further given.Finally,the paper discussed the influence of slenderness ratio and section width of vertical steel strip on the bearing capacity,and gave the design suggestions of steel strip to guide the design and construction of such projects.