| In China,there are large quantities of existing brick masonry structures,and most of them have insufficient seismic bearing capacity,which is of great practical significance for seismic strengthening of these buildings.The use of modified reactive powder concrete surface to reinforce brick wall has many advantages,such as small reinforcement thickness,good reinforcement effect,convenient construction,high temperature resistance,economic and environmental protection,etc.,so as to meet the requirements of the state for environmental protection.In this paper,the traditional reactive powder concrete has been modified,which has changed its fluidity and plasticity.The fluidity and the strength of the modified concrete have been reduced,and the plasticity requirements and strength requirements for the reinforcement of brick wall surface have been met.On the basis of the study on the pseudo static test of 6 brick walls,6 walls are divided into two groups,The size of the first group of walls is 1740mm×1008mm,and the size of the second groups is 2240mm×1008mm,each group of specimens including 1 pieces of unreinforced walls,1 pieces of wall reinforced by MRPC-1 material on both sides of the wall,1 pieces of damaged wall reinforced by MRPC-2 material.The cyclic loading test of reinforced wall,mainly studied the reinforced failure mode,shear capacity,stiffness degradation trend,hysteretic behavior,energy dissipation capacity and ductility and seismic performance,and deduced the bearing capacity of MRPC reinforced wall.The conclusions are as follows:1.for undamaged wall reinforced by MRPC-1,two kinds of high aspect ratio limit bearing capacity of the strengthened walls were increased to 2.93 times and 3.27 times,producing a small amount of visible cracks,pry the surface layer of concrete structures found that the bottom of the column and corner Department of bricks was severely crushed.2.for damaged wall reinforcement by MRPC-2,two kinds of high aspect ratio limit bearing capacity of the strengthened walls were increased to 1.84 times and 1.55 times,More "discontinuous" cracks in the surface layer,destroy the specimens by combining surface layer and the surface layer and the wall from the way,increase the energy dissipation capacity of the wall.3.from the skeleton curve can be seen,There is a common feature of wall reinforcement with MRPC material,that is,after reaching the ultimate bearing capacity,there will be a short sliding section followed by a long horizontal section,which is called "the stable period of bearing capacity".The bearing capacity of this stage is basically unchanged,and there will be a slight increase trend in the later period,Under this bearing capacity,the brick wall can reach the displacement of more than 30 mm for the the undamaged wall reinforced by MRPC-1,the bearing capacity of the " stability " is not the ultimate bearing capacity of the strengthened walls 1.71 times and 1.64 times;For the damaged wall reinforced by MRPC-2,the bearing capacity of the "stable period" is 1.11 times and 1.18 times the ultimate bearing capacity of the unreinforced wall.4.from the stiffness degradation curve,it can be seen that the curve of the wall after reinforcement is slower than that of the unreinforced wall,especially the undamaged wall strengthened by MRPC-1 material.The stiffness degradation curve will have uplift in the middle part,and the stiffness degradation will be slow.5.according to the "stable" as the failure point of the wall,The ultimate displacement of the reinforced wall is more than 2 times of the ultimate displacement of the unreinforced wall.;The energy dissipation capacity of the single cycle is 4.8 times and 6.4 times that of the unreinforced wall respectively after the two types of height and width ratio are strengthened;reinforced ductility coefficient of wall it has been greatly improved. |
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