| In order to solve the problem of unstable welding quality of the existing steel sheet-concrete composite shear wall,this thesis designed seven new assembled double-layer steel sheet-concrete composite shear wall specimens with vertical joints and bolts connected with steel truss and carried out low cycle reciprocating load tests on the premise of maintaining the mechanical properties of the composite shear wall and from the point of view of convenient construction and stable welding quality.The effects of the vertical steel plate splicing mode of the wall body,the section size of the edge members and the shear span ratio on the mechanical and seismic properties of the new composite wall were analyzed.On the basis of the test,the finite element model of the new composite shear wall was established by ABAQUS software,and the effects of axial compression ratio,concrete strength,wall steel plate strength,wall steel plate thickness,edge member side length and steel content on the seismic performance of the new composite wall were further studied.Finally,the simplified dimensionless skeleton curve of the specimen was obtained by using the test fitting method.According to the force balance,the formulas of the flexural and shear bearing capacity of the combined shear wall were deduced and verified.The work carried out in this thesis and the conclusions drawn mainly included the following aspects:(1)Seven new composite walls with different steel plate splintering modes,shear span ratio and section size of edge members were designed,and low-cycle reciprocating load test analysis was carried out.The research showed that: compared with the composite shear wall with 210 mm bolted connection in the center,the stiffness and bearing capacity of the composite wall with fully bolted connection deteriorated more slowly after peak load.When the side length of the edge member increased from 100 mm to 250 mm,the initial lateral stiffness of the composite wall increased by 141.10%～200.25%,the peak load increased by149.55%～158.40%,and the cumulative hysteretic energy consumption increased by the maximum 152.66%.Increasing the section size of the edge member significantly improved the bearing capacity and energy dissipation capacity of the specimen.When the shear span ratio decreased from 3.0 to 2.0,the initial lateral stiffness of the new composite wall increased by 102.34%,the peak load increased by 84.30%,the cumulative hysteretic energy consumption increased by 24.22%,and the bearing capacity and stiffness degradation are stable,indicating that the new composite shear wall with a shear span ratio of 2.0 also presented a stable load-holding capacity.Compared with the composite wall without rubber pad at the bottom of the wall,the initial lateral stiffness of the composite wall with rubber pad at the bottom of the wall was reduced by 40.33%,the peak load was reduced by 31.42%,and the cumulative hysteretic energy consumption was reduced by 31.97%.However,the bearing capacity degradation was slower and the ductility coefficient is higher,indicating that although the rubber pad locally weakens the wall stiffness,But it played the role of protecting wall bearing capacity.(2)On the basis of the experimental study,seven new combined shear wall specimens were simulated by ABAQUS finite element method,and the simulation results were in good agreement with the test results.The effects of axial compression ratio,shear span ratio,concrete strength,steel plate strength,wall plate thickness,edge length and steel content on the seismic performance of the new composite wall were further analyzed.The analysis results showed that: With the increase of the side length and steel content of the edge members of shear wall,the increase of the strength grade of concrete,the increase of the strength grade of steel plate and the increase of the thickness of steel plate,the bearing capacity of shear wall has been improved.The side length of the edge members has the best effect on the bearing capacity of the new combined shear wall.Under the condition of constant hoop coefficient,every 50 mm increase of the side length of the edge members,The increase range of yield load and bearing capacity of the new composite shear wall was about37%～61%,but the strength degradation rate of the skeleton curve after the peak load was also faster.When the axial compression ratio of the new composite shear wall is 0.4,the initial stiffness,yield load and bearing capacity of the shear wall take a larger value.When the axial compression ratio is greater than 0.4,the bearing capacity degraded quickly after the peak load.When the shear span ratio increases by 0.5,the yield load and peak load decreased by18%～31%,and the ductility also decreased.(3)By the method of test fitting,the skeleton curve of the test results of the new combined shear wall was treated dimensionless,and the section expression of the simplified three-fold model was given.At the same time,based on the finite element numerical analysis,the stress process,stress deformation form and cross section strain distribution of the new composite wall in this test were analyzed,and the formulas of flexural and shear bearing capacity of the new composite wall were derived.The average value of the ratio between the calculated value and the test value of the flexural bearing capacity of the specimen was 1.03,and the variance was 0.03.The average value and variance of the ratio between the calculated value and the test value were 1.07 and 0.007,indicating that the calculated results are in good agreement with the test results,which can provide reference for the design and construction of this type of prefabricated composite shear wall. |
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