Studies On In-plane Seismic Behavior Of Double-steel-concrete Composite Shear Walls

Double-steel-concrete composite shear wall is a kind of composite structures consisting of outside double steel plates and filled concrete.It can make full use of mechanical properties of steel and concrete,and has good mechanical properties.These years,double-steel-concrete composite shear walls have been widely used in civil buildings and nuclear power plants.However,domestic researches mainly focus on axial compressive performance and flexural behavior.Researches about shear behavior are far from sufficient and there is not a mature design method.Based on the experimental studies of double-steel-concrete composite shear wall specimens and the results of detailed finite element models,shear behavior of double-steel-concrete composite shear walls is studied.The main works and research results are as follows.(1)Quasi-static tests on 10 low shear-span ratio double-steel-concrete composite shear wall specimens were conducted,in order to analyze seismic behavior of specimens and effects of details of connections between steel plates and concrete plates,axial compression ratio,concrete strength,shear-span ratio and distance to thickness ratio..The following conclusions were drawn from the tests.The failures of the ten low shear-span ratio specimens are all shear failures.Top lateral load-displacement hysteretic loops are nearly full,which means the specimens have good deformation performances and energy dissipation capacity.Local failure has a seriously effect on deformation capacity and ductility of the specimen.The increase of the design axial compression ratio and concrete strength leads to larger initial stiffness,lower deformation capacity.Ductility of double-steel-concrete composite shear wall with smaller distance to thickness ratio is better.Shear bearing capacity is lower with smaller shear-span ratio,but deformation capacity and ductility of the specimens are better.(2)Detailed finite element models of double-steel-concrete composite shear wall specimens were constructed and bearing capacity and buckling patterns were analyzed by means of ABAQUS,a finite element software.At the same time,the influences of axial compression ratio,concrete strength,steel strength,steel ratio and details of connections between steel plates and concrete are analyzed.The following results can be concluded from parameter analysis.Bearing capacity,deformation capacity and ductility of the specimens are little affected by axial compression ratio when axial compression ratio is not more than 0.3.However,when the axial compression ratio is greater than 0.3,bearing capacity,deformation capacity and ductility of the specimens decreased with the increasing of axial compression ratio.The bearing capacity of specimens is positively correlated with the strength of concrete and the steel.The increase of strength of the wall steel contributes more to the increase of the bearing capacity than that of the column steel.Bearing capacity of the specimens but not ductility is little affected by details of shear connectors and the distance to thickness ratio.(3)By analyzing the test results and the computing results of finite element models,the modified shear capacity formula of double-steel-concrete composite shear wall that is recommended in this research is acquired on the base of the shear capacity formula of steel plate reinforced concrete shear wall,which has considered composite effects among parts of double-steel-concrete composite shear wall.