Experimental Study On Seismic Performance Of MRPC-reinforced Masonry Walls With Structural Columns With Different Height-to-width Ratios

As one of the most widely used structures in my country,masonry structures are often more damaged than other structures such as reinforced concrete after earthquakes due to their shortcomings such as poor adhesion,low strength and poor integrity.The existing masonry structure buildings have problems such as long-term construction,substandard seismic measures,and poor construction quality.However,the number of masonry structure buildings is huge,and it is difficult to demolish them in a short period of time due to various factors.realistic.According to the characteristics of earthquake damage in the past,the current design code emphasizes the concept of "strong columns and weak beams".If the entire longitudinal wall is compared to a "strong column and weak beam" model,the wall between windows and the wall under the window can be regarded as vertical vertical walls.For components and horizontal components,it is required that the wall between the windows should be damaged after the wall below the window,so as to ensure local damage and reduce the damage to the overall structure.In addition,under the influence of earthquake damage,the wall between windows in masonry engineering is mostly damaged by shear,and the aspect ratio of the wall has a great influence on the stress distribution and damage form of the specimen section.In this thesis,the main research object is masonry inter-window walls with different height-to-width ratios with structural columns.Quasi-static tests are used to test the low-strength masonry inter-window walls reinforced with modified reactive powder concrete(MRPC)surfaces on both sides.Experimental study to quantify the reinforcement effect of MRPC surfacing on the seismic performance of masonry inter-window walls.The main contents and conclusions of this thesis include:(1)By controlling the conditions of MRPC water-binder ratio,mortar ratio,fiber content and water-reducing agent content,MRPC materials with good fluidity and strong plasticity are formulated,and the bonding performance between MRPC and ordinary concrete is tested.After the experiment,the optimal mix ratio of MRPC material suitable for plastering surface reinforcement was finally obtained,which has the characteristics of good fluidity,strong plasticity and strong adhesion to the wall.(2)The MRPC surface layer is used to reinforce the masonry inter-window wall,and the quasi-static loading test is carried out on one unreinforced wall and three MRPC surfaces reinforced with different height-to-width ratios.The seismic performance in terms of recoil characteristics and stiffness degradation was analyzed to analyze the effect of MRPC surface layer strengthening the brick masonry wall between windows,and calculate the corresponding shear bearing capacity of the four brick masonry walls.(3)MRPC surface layer reinforcement of masonry inter-window walls can exert its high strength and high ductility characteristics,can improve the brittle failure characteristics of brick masonry walls,and effectively improve the wall stiffness,ductility,energy dissipation capacity and other seismic performance,MRPC surface The reinforced masonry inter-window wall can realize the failure mode of "strong column and weak beam",changing the masonry wall from the original shear failure to the bending failure,improving the overall ductility and bearing capacity of the masonry inter-window wall,so as to achieve the masonry wall.The ideal damage effect of the wall between the body and the window under the action of the earthquake reduces the loss caused by the earthquake,and the construction is simple and free of formwork,which can save manpower and material resources.(4)The MRPC surface layer reinforces the masonry inter-window walls with different aspect ratios.Compared with the unreinforced walls,the seismic performance is improved in all aspects.The more obvious the effect of MRPC surface layer strengthening the masonry inter-window wall in improving the brittle failure characteristics of the wall,the higher the displacement ductility coefficient,the flexural resistance and ductility of the wall are gradually enhanced,the number of hysteresis loops increases,and the hysteresis loop package The network area continues to increase,and the cumulative energy consumption increases at the same time.(5)The difference between the experimental value and the calculated value of the shear bearing capacity of the masonry inter-window wall reinforced by MRPC surface layer is small,which provides the experimental basis and theoretical basis for the engineering promotion of MRPC surface layer reinforced masonry inter-window wall.