Study On Mechanical Performance Of Adobe Masonry Reinforced By Glass-Fiber Mesh

The adobe masonry structure has a long history and has been used for thousands of years.Nowadays,there are still a lot of houses built in this form in most rural areas of China,some of which have become national historical relics and play an important role in the inheritance of national culture.However,due to the long history and the experience of local craftsmen,the quality of the construction is difficult to be guaranteed,and it is often seriously damaged in the earthquake.This paper is supported by the National Natural Science Foundation of China: Study on the bonding mechanism and seismic performance of adobe masonry reinforced by polymer Fiber net surface layer.Glass Fiber net,epoxy resin and polyurethane modified clay are used as the reinforcement materials of adobe masonry.Polymer Fiber net and epoxy resin are respectively used to bond the adobe masonry(Fiber Reinforced Polymer Mesh,FRP Mesh,Fiber Reinforced Polymer Mesh with Soil Mortar,Fiber Reinforced Polymer Mesh with Soil Mortar(FRPSM)and polymer Fiber network + modified soil layer(FRSM)are used to strengthen adobe masonry and wall specimens.At the same time,in order to study various reinforcement methods of adobe masonry wall under the basic mechanical properties,this article from a single piece of the clay brick production and compressive strength,glass fibres,and the basic mechanical properties of reinforced material,the mechanical properties of adobe masonry specimens,and the mechanical properties of adobe masonry wall,these four aspects,respectively through the test research,theoretical analysis and numerical calculation,Some experimental results for reference are obtained.The main contents are as follows:(1)by geotechnical test,analyzes the dalian silty clay and sand soil of fujian province of grain size distribution,limit moisture content,the optimum moisture content,dry density and the corresponding parameters,select the appropriate Tu Sha mixing ratio and moisture content,used for clay brick production,and through the adobe brick facade uniaxial compression test,its reliability is verified.It can be found that there is a direct relationship between the compressive strength of adobe brick and its failure mode.When the distribution of particles inside the soil is more uniform and the compaction degree is better,the adobe brick is prone to axial compression and shear failure mode,and its strength is higher,otherwise,it is prone to local compression failure mode,resulting in lower strength phenomenon.Therefore,the quality of adobe brick can be greatly increased by selecting the proper proportion of soil and sand and ensuring its compactness in the process of making adobe brick.(2)The basic mechanical properties of the glass fiber material were analyzed by the pull-out test of the fiber net.The results show that the glass fiber material,on the basis of the variation characteristics of average elastic material,also has a strong tensile property,which can fully meet the reinforcement requirements of adobe masonry structure.At the same time,through the uniaxial compression test of clay,the comparison analysis shows that the lifting effect of polyurethane used in clay reinforcement.The results show that polyurethane and clay materials have good applicability,and the compressive strength of the reinforced specimens can be increased by 107%.(3)Through the compression and shear tests of adobe masonry,it is found that the failure modes of compression and shear specimens of unreinforced adobe masonry are basically similar to those of common brick masonry specimens.In the middle of the masonry specimen under pressure,there is a splitting failure along the vertical crack,and in the contact surface between the brick and the mud,there is a shear bonding failure.After the FRSM method was adopted to strengthen the specimens,the reinforced surface layers were peeled off when the specimens were subjected to loads,thus sharing the load on the original masonry specimens,making the compressive strength and shear strength of the specimens significantly improved by 14.3% and 102.2%,respectively.However,with the peeling off of the reinforced surface layers,The original masonry specimens began to show the same failure patterns as the unreinforced specimens.However,after FRP MESH and FRPSM were used to strengthen the specimens,due to the good bonding effect of epoxy resin,the reinforced surface layer was not separated from the original masonry structure when subjected to loads.In addition,the overall strength of the reinforced surface layer was relatively large,which greatly increased the strength of the specimens,and the compressive strength increased by 47.1% and 63.6%,respectively.The shear strength increased by more than two times.At the same time,the failure modes of masonry specimens have also changed.Under uniaxial compression,vertical cracks appeared on the sides of masonry specimens.Under shear,the slurry and ash joints remained intact,and vertical cracks appeared on the sides of specimens.The results show that the three reinforcement methods have significant effects on the improvement of mechanical properties of adobe masonry.(4)The mechanical properties of solid unreinforced adobe walls and reinforced adobe walls using FRPSM and FRSM were studied by plane pseudo-static tests.The research shows that the failure mode of the unreinforced adobe wall is basically similar to that of the ordinary brick masonry wall,which is the shear and friction failure along the ash seam.The overall sliding failure occurs at the bottom of the wall after the FRPSM method is adopted due to the high overall strength.The strengthened surface layer and the original wall gradually peel off,and then the wall is damaged,which is similar to the unstrengthened wall.At the same time,the bearing capacity,ductility,stiffness and energy dissipation capacity of the wall specimens are significantly improved by using the FRPSM and FRSM methods,and in terms of the lifting effect,the FRPSM is obviously better than the FRSM.(5)Based on the results of plane quasi-static tests,it is found that the ultimate bearing capacity of unreinforced wall specimens is larger than that of main tensile theory and smaller than that of shear-friction theory,and its numerical characteristics are similar to those of ordinary brick masonry.At the same time,under the calculation model of Ramo theory,when the distribution coefficient of vertical stress is 0.6,the test results are basically consistent with the calculated values.For the ultimate bearing capacity of wall specimens reinforced by FRPSM and FRSM,a simple calculation model is established by referring to the calculation process of common brick masonry wall reinforcement method,and the calculation formula of reinforcement is put forward,which is in good agreement with the test results.