Cyclic Test On Double-skin Recycled Concrete Filled Composite Shear Walls

Double-skin recycled concrete filled composite shear wall is an innovative lateral force-resisting system,which consists of two exterior steel plates,infilled recycled aggregate concrete(RAC),steel-concrete connectors and two rectangular RAC-filled steel tubes serving as the wall boundary elements.This kind of composite shear wall has advantages of superior seismic performance and convenient construction.Besides,it can effectively promote the utilization of Construction Waste Resource.In this paper,the seismic performance of this new type of composite shear wall is studied by combining experimental,finite element simulation and theoretical analysis.The main research work and results are as follows:(1)Five groups of the recycled coarse aggregate(RCA)replacement percentage of 0%,30%,50%,70% and 100% were prepared by "pre-absorbing water" method and corresponding material property tests were conducted.The results shown that the strength of RAC with different RCA replacement percentage fluctuated within 5% range.With the increase of RCA replacement percentage,the compressive modulus of elasticity of RAC decreased gradually,and the reduction range was less than 6%.The formula for calculating the compressive modulus of elasticity in current codes is revised by introducing the parameter called RCA replacement percentage ?.Based on the constitutive equation of concrete proposed by Guo Zhenhai,the equation for the rising section of the RAC constitutive model was obtained through data-fitting.(2)Quasi-static cyclic tests were conducted on three double-skin recycled concrete filled composite shear walls with 1:3 scale and a shear span ratio of 1.5.All 3 specimens had high lateral capacity,ductility and energy dissipation capacity,and exhibited excellent seismic performance.After replacing the concrete with RAC that has a RCA replacement percentage of 100% in the double-skin composite wall with flat exterior plates,the peak load was reduced by 5.7% and the displacement ductility factor decreased from 4.40 to 3.86.The peak load increased by 17.6% and the displacement ductility factor increased from 3.86 to 4.17,after changing the exterior plates to corrugated plates in the previous specimen.Therefore,when RAC was adopted in in double-skin composite shear walls,the lateral capacity and ductility ratio were reduced to some extent,while using corrugated external plates increased the lateral capacity and ductility ratio effectively.(3)Numerical analyses of the test specimens were carried out using the finite element software ABAQUS,and the models were verified by nonlinear push-over analysis.Parametric studies were carried out on 63 finite-element models of doubleskin composite walls,and the results showed that using corrugated plates could alleviate the negative influence of RAC on seismic resistance of composite walls,and influence pattern of steel plate thickness,steel strength,RAC strength,axial force ratio on the lateral behavior of double-skin recycled concrete filled composite shear walls were studied.(4)Based on experimental results and related theoretical research,a simplified formula for the compression-bending capacity of double-skin recycled concrete filled composite shear walls was derived.The calculation results of the formula were in good agreement with the experimental results,and the formula has a certain safety reserve.