| Masonry structure is widely used in industrial and civil buildings because of its advantages of simple construction process,convenient material extraction and low cost,but due to the high self-weight of masonry structure and poor bending and shear resistance of the walls,it has been seriously damaged in successive earthquake disasters.A large number of masonry buildings have been constructed during the rapid development of China in the past40 years,and these buildings generally suffer from inadequate bearing capacity and seismic performance due to early design defects,material deterioration and structural damage during use,and require seismic strengthening.In response to this situation,this paper proposes a combined reinforcement method of reinforced mesh mortar surface and concrete column applicable to the seismic strengthening of brick masonry structures,and investigates the seismic performance improvement of the combined reinforced masonry and its influencing factors based on the finite element numerical simulation method.The main research contents of this paper are as follows:(1)The mechanical properties of brick masonry and reinforcing materials are analyzed,and then the ontological relationships of each material and the selection of interface parameters are given.A finite element modeling method applicable to the analysis of the reinforcing performance of brick masonry walls is developed on the basis of reasonable mechanical assumptions.In combination with the existing experiments,a numerical model of eight masonry walls was established using ABAQUS,and the feasibility of the used reinforced masonry modeling method was verified through various comparisons.(2)The mechanical properties of brick masonry walls reinforced by different methods were analyzed to explore the effects of different reinforcement methods on the seismic performance of the walls,and the synergistic working relationship between the combined reinforcing members and the masonry walls was analyzed.The results show that: each reinforcement method can effectively improve the shear bearing capacity and slow down the degradation rate of wall stiffness,among which the improvement of the seismic performance of the wall by the combined reinforcement method is better than that by the single reinforcement method;when using the combined reinforcement method,the synergy between the reinforcement members and the masonry wall is good,the proportion of the horizontal load borne by the reinforcement members is higher than that by the single reinforcement method,and the compensation of the horizontal bearing capacity of the wall by the reinforcement members appears earlier.The compensation phenomenon appears earlier.(3)The thickness and strength of mortar surface layer,wall height-width ratio,opening rate and vertical compressive stress were selected as parameters,and a numerical model of 84 pieces of walls under different parameters was established to systematically study the influence law of different factors on the shear bearing capacity of combined reinforced masonry walls.The results show that: with the increase of vertical compressive stress of the wall,the shear bearing capacity of the combination reinforced wall gradually increases,and this phenomenon is more obvious in the wall with larger height to width ratio;when the thickness of mortar surface layer increases,the shear bearing capacity of the combination reinforced wall increases,and the difference of shear bearing capacity increment between the combination reinforced walls with different thickness of mortar surface layer expands with the increase of vertical compressive stress;when the opening rate of the wall is less than When the wall opening rate is less than 45%,the effect of combined reinforcement on the shear bearing capacity of the wall with high opening rate is more significant.(4)Taking the reinforcement and renovation project of a middle school in Gaolan as an example,the simplified masonry structure model before and after the combined reinforcement was established and the elastic-plastic time analysis was carried out.The damage of both longitudinal and transverse walls of the masonry structure under the action of rare earthquakes was improved after the combined reinforcement,among which the damage of longitudinal walls was reduced more obviously;the maximum displacement angle between layers of the masonry structure was reduced after the combined reinforcement,among which the maximum displacement angle between layers of the first floor of the structure was reduced most obviously.The above results show that the combination of reinforced mesh mortar surface layer and concrete column reinforcement can effectively improve the shear bearing capacity and ductility of brick masonry walls,reduce the damage of brick masonry structure under earthquake action,and achieve the reinforcement purpose of enhancing the seismic performance of masonry structure,and this reinforcement method has good application prospects. |
