Experimental Research On Mechanical Properties Of Rubber Isolation Bearing And Construction To Rural Low-rise Masonry Structure

Rural areas and population are widely distributed in our country,but the seismic performance of village buildings is poor.Villages and towns became hard-hit areas in the past earthquakes.As the main structure form of villages in China,a large number of low-rise masonry structure collapsing and destroying in earthquake were the important factors causing casualties and property losses.As a result, improving the seismic resistance of low-rise masonry structure building and promoting the application of new technology are the key to solve the seismic problem of rural building.The base-isolated technology with rubber bearings was commonly used in multi-storey and tall buildings,high importance buildings.Isolation design research on those buildings was more mature.Due to the large diameter of bearing,isolation groove and bottom floor need to be set.Such design led to a high cost,complex construction and was difficult to apply in villages and towns buildings in our country.In view of the structure characteristics of rural low-rise masonry structure,minor-diameter bearing was designed.In order to reduce costs and simplify construction,position of isolation layer was lifted and the corresponding construction measures were designed.Mechanical properties and isolation effect of minor-diameter bearing,feasibility and rationality of isolation layer construction need to be researched.The following research work was carried out:(1)For the generally characteristics of low-rise masonry structure houses such as symmetrical plane layout,small size and low vertical load,according to the common wall body size,5 kinds of small diameter rubber isolation bearings were designed.Equivalent stiffness,post-yield stiffness,equivalent damping ratio and vertical stiffness were given by test.Impact of horizontal shear strain,test loading rate and the coefficient of the second shape on equivalent stiffness,post-yield stiffness and hysteretic behavior were analyzed.(2)The damping coefficient and horizontal displacement of the bearings were calculated and compared.The curves and the fitting formulas on the relationship between horizontal displacement,damping coefficient and its influence factors were gained.Thereference to design and selection of rubber isolation bearings used in low-rise masonry structure was provided.(3)To reduce the costs and make construction convenient,the isolation groove and bottom slab were not set.Seting the isolation layer above the indoor floor and solving the corresponding construction design of isolation layer disconnect in door hole and stairs,waterproof sealing,etc.The construction measures did not affect the deformation of isolation bearing.Feasibility of the design and corresponding construction was verified by overall structure model test study.(4)The dynamic characteristics,acceleration,displacement and shear force of isolated and non-isolated masonry structure models are analyzed by numerical simulation.Isolation model had good vibration isolation effect through comparison and the results were verified by overall structure model test study under seismic loading.