The Experimental Investigation Of Seismic Performance On The Brick Wall Constrained By Structural Column And Strengthened By Reinforced Cement

Masonry structure has widely used in all countries in the world, because of its low cost, easily getting materials at hand, good fire resistance and good thermal insulation performance and construction advantages of easy operation. But masonry structure especially the integrity of the unreinforced masonry structure is poor, low bearing capacity. Because of the lower mortar strength, the weakness of seismic structural measures seismic performance is poor. After the founding of our country, a large number of masonry structure buildings has been created. A large proportion were close to the design reference period. Many buildings for a variety of factors present material performance degradation for a variety of factors. Furthermore, with the continuous development of our country's economy, the structure of the design standards and codes are also constantly improve. Many of the existing masonry structures cannot meet the current safety standards. Research on masonry structure seismic strengthening technology of masonry structure to improve the seismic performance of masonry structure, reduce the earthquake caused economic losses and casualties is very important.Steel mesh cement mortar layer reinforcement method can obviously affect the seismic bearing capacity and ductility of the wall. And the construction technology is relatively simple, so it is one of the most commonly used methods currently used in the seismic strengthening of masonry structure. The consideration of current research is not comprehensive. The constraint of the constructional column has not been considered. In addition, we can consider to use the method of both adding constructional column steel mesh cement mortar layer to the wall without setting constructional column, in order to ensure the effective anchorage of the horizontal bar. We should keep eye on the shear mechanism of the wall enhanced by steel mesh cement mortar layer, considering the advantage of structural column at end and the formula of seismic shear bearing capacity. It has important guiding significance to engineering reinforcement. What's more. We can have brick wall seismic strengthening design more reasonable and save resources.In this article, the ten pieces of brick walls, with steel mesh cement mortar and side column strengthened, had been test researched. It shows that the seismic performance of brick wall has improved significantly. We can get the following conclusions from the analysis of the test result. Firstly, the constructional column, which is the combinations of brick masonry and reinforced concrete, has the same effect comparing to the common one, and it can mprove the seismic performance of masonry. Secondly, wo can strengthen the wall, which has consolidated by constructional column, by steel mesh mortar layer. And with appropriate constructional column spacing, the damage form of brick wall can convert brittle shear failure to partial plastic bending damage. Thirdly, the failure process is divided into three distinct stages:the elastic stage, the elastic-plastic stage and failure stage. Fourthly, the skeleton curve of the specimens can be simplified into three line model and we can obviously find that three factors all have regular influence to the curve, and the influence of the aspect ratio is the largest. Fifthly, ductility represents deformation ability of structural elastic-plastic stage, the bigger the ratio, the better the ductility of the specimens, the more the constructional column reinforcement the better the ductility of the specimens, the axial compression ratio, the greater the ductility of the specimens. Sixthly, considering three factors, height to width ratio has the biggest influence on cracking stiffness, the bigger of height to width ratio the smaller of cracking stiffness. Crack stiffness decreases with increasing of the constructional column reinforcement, and the influence of axial compression ratio on cracking stiffness is not regular, as no effect. The seventh, before the cracking of the wall, the stiffness curve basic keep as straight line. It falls sharply, because of the quickly developing of early cracks and the appearing of new cracks. At the later stage of developing of crack, development focuses on weak parts of the wall. The other parts of the wall have no development because they can't share the load. At this stage, damage accumulation is slow, so the line become gently. After reaching the limit load, cracks will not appear and develop. The main phenomenon is that the pressure side began to be crushed slowly and the stretching steel is becoming longer as the increasing displacement. The stiffness curve declines slowly, closing to be horizontal. The eighth, based on the damage of specimens and the data analysis, the cracking of specimen can be simplified as a cantilever beam model, and we can use the formula of maximum stress of the bending section under the action of bending moment, then cracking load is deduced. The ninth, specimen at the point of limit load can be simplified as frame structure of triangle, and the formula of limit load is given.