| Shear walls have become the most basic and common lateral force resistance unit and are widely used in a variety of lateral force resistance structural systems for the reason that it can effectively resist horizontal and vertical loads in high-rise building structures.With the country’s requirements for double carbon and the continuous improvement of construction quality and construction efficiency,traditional cast-in-place reinforced concrete(RC)shear walls can no longer meet the current design needs of multi-and high-rise buildings.RC shear walls usually need to take measures such as increasing the section and improving the material strength to meet the design requirements,which will reduce the building area,increase the building cost,and increase the seismic distribution of the base.The steelconcrete composite shear wall structure system combines the advantages of the two materials to form a lateral force resistance unit with light weight,low cost and small section,which provides a new direction for solving the above problems.Therefore,the new composite shear wall The structural form needs to be studied and applied urgently..The steel-concrete composite tube shear wall structure system is a new type of steelconcrete composite shear wall structure system.The wall is composed of precast steelconcrete composite tube(SRCCT)and cast-in-place concrete.The prefabricated construction process has the advantages of high bearing capacity,high construction efficiency,low fire protection and anti-corrosion costs,and broad development prospects.In this paper,the seismic performance of the precast SRCCT shear wall is explored through experimental research,theoretical derivation and finite element analysis.The main research contents are as follows:(1)The quasi-static test of the precast SRCCT shear wall was completed,its bearing capacity and deformation capacity were studied,and the failure mode and stress mechanism of the wall were investigated.The seismic performance tests of 4SRCCT shear wall specimens with different axial compression ratios and steel content ratios and a cast-in-place comparative specimen were carried out,and their stress failures under the combined action of horizontal and vertical loads were analyzed.The seismic performance indicators such as hysteresis curve,skeleton curve,bearing capacity,displacement ductility,stiffness degradation and energy dissipation capacity are studied.stress mechanism.Compared with the cast-in-place specimen,the initial stiffness of the SRCCT shear wall in the design failure state increased by 155%,the peak bearing capacity increased by 137%,and the displacement ductility coefficient increased by 30%.It is a new type of combined shear force with excellent seismic performance.wall structure.(2)Based on the mechanical principles and reasonable assumptions,the formulas for calculating the normal section bearing capacity and initial stiffness of the SRCCT shear wall are deduced.By analyzing the failure form and section strain development law of SRCCT shear wall under low-cycle cyclic load,and based on the principle of material mechanics,the stress state of each component of the wall under low-cycle cyclic load is analyzed.The constraint of steel tube and the constraint of rectangular steel tube to the concrete in the tube,the calculation formula of the normal section bearing capacity of the SRCCT shear wall is deduced;based on the structural mechanics and superposition theory,the calculation formula of the initial stiffness of the wall is deduced;The calculated value of cross-section bearing capacity and the calculated value of initial stiffness are compared with the test to verify the reliability of the calculation method.(3)A finite element analysis model of the precast SRCCT shear wall under the combined action of horizontal and vertical loads was established to further explore the mechanical performance of the wall.The non-linear analysis of the precast SRCCT shear wall was carried out by using the numerical simulation program.Compared with the loaddisplacement curve and the failure mode obtained from the test,the correctness of the modeling method was verified,and the stress of its main components was analyzed.The stress distribution law under the whole process,and the strain development law of the connection node at the bottom of the SRCCT shear wall is studied,which shows that the connection node at the bottom can provide effective restraint before the peak load.The influence of parameters such as axial compression ratio,concrete compressive strength,steel plate thickness,steel strength and shear-span ratio on the mechanical performance of the precast SRCCT shear wall is studied through orthogonal parametric analysis.If it is greater than 0.4,the concrete strength grade should not be higher than C50,the thickness of the steel plate should be 3-5mm,the steel strength grade should not be higher than Q420,and the shear-span ratio should be 1.0-2.0.This paper completes the quasi-static test of the new SRCCT shear wall,analyzes the hysteretic performance,bearing capacity,deformation capacity,stiffness degradation,energy dissipation capacity and strain development of the shear wall,and compares it with the castin-place specimen.,the results show that the SRCCT shear wall is a new type of composite wall with excellent seismic performance.By analyzing the wall failure form and strain development law,a calculation model for the normal section bearing capacity and initial stiffness of the SRCCT shear wall is established.The nonlinear finite element analysis method is proposed,the stress development law of the whole process of the SRCCT shear wall is analyzed,and the orthogonal parametric analysis is carried out to propose design recommendations.The research results can provide reference for the engineering application of SRCCT shear wall structure. |
