Seismic Performance And Restoring Force Model Of The Composite Wall With Longitudinal Rib Reinforcement

The composite wall structure system with longitudinal stiffeners is proposed on the basis of multi ribbed composite wall,which is composed of lightweight thermal insulation block and concealed frame.The system has many advantages such as relatively low cost,less equipment dependence and simple construction technology,which is suitable for application in high intensity and remote villages and towns in China.As an important part of the wall,block and rib beam have great influence on the seismic performance of the wall.In order to study the influence of different block strength and rib beam reinforcement ratio on the seismic performance of the wall,and to establish the restoring force model of the wall,the wall was studied by combining experimental research,finite element simulation and theoretical analysis.The specific research contents and conclusions are as follows:(1)Three 1/2 ratio composite walls with Longitudinal Stiffeners under different working conditions were designed and manufactured,and the effects of different block strength and rib beam reinforcement ratio on the failure process,failure mode,bearing capacity and seismic performance of the wall were studied by pseudo static test.The results show that: the three walls experienced three stages of elasticity,elastoplasticity and failure in the whole loading process;The filled block can significantly improve the shear capacity of the wall,and also improve the ductility of the wall,so that the wall can achieve three seismic defense lines;The increase of rib beam reinforcement ratio improves the shear capacity of the wall,but reduces the ductility of the wall.(2)Three groups of wall models with different block strength,rib reinforcement ratio and axial compression ratio were established by using ABAQUS finite element simulation software,and the simulation was carried out to study the influence of various factors on the bearing capacity and seismic performance of the wall,and the optimal block strength and rib reinforcement ratio of the wall were proposed.The results show that: the filled block has a significant impact on the seismic performance of the wall.With the increase of the strength of the filled block,the shear capacity of the wall also increases,especially when the strength of the filled block is low.The bearing capacity of the wall filled with 2.0MPa block is 3.7 times higher than that of the wall without filled block,and the initial stiffness is more than 10 times higher;The reinforcement ratio of rib beam has a certain influence on the seismic performance of wall,when the reinforcement ratio increases from 0.5% to 4.0%,the shear capacity of the wall increases by77%;When the axial compression ratio increases from 0 to 0.5,the shear capacity of the wall increases by33%,and the stiffness increases by 2.2 times.The ductility and deformation properties of the wall do not change greatly with the change of axial compression ratio.The best block strength range of the wall is2.5-7.5mpa,and the best rib reinforcement ratio range is 2.2-3.4%.(3)According to the low cycle repeated loading test of composite wall with Longitudinal Stiffeners under different working conditions,the restoring force model of composite wall with longitudinal stiffeners is established by using the four linear restoring force model through the combination of test fitting and theoretical calculation,and the calculation results are compared with the test results.Finally,the time history analysis of the actual project is carried out by SAP2000 finite element simulation software,and the results are compared with the previous results The research results are compared.The results show that: The calculation formula has good accuracy,and the skeleton curve can effectively reflect the relationship between the wall load and displacement;The results show that the stiffness degradation rule and the hysteretic rule can reflect the hysteretic rule of the wall;The restoring force model based on the four line restoring force model can better reflect the mechanical performance of the composite wall with longitudinal stiffeners;According to the wall test,the restoring force model and the distribution law of axial compression load in this paper,the mechanical performance of the wall under earthquake can be well reflected,and it can be used for the elastic-plastic seismic response analysis of composite wall with longitudinal stiffeners.