| With the rapid development of the national economy and the rapid advancement of the new urbanization process,the urban population has grown rapidly in recent years.In order to solve the problem of dense population,high-rise and ultra-high-rise buildings have been greatly developed.Reinforced concrete(RC)shear walls,as the main anti-lateral force component in high-rise and ultra high-rise buildings,have certain limitations in economy and seismic performance.In recent years,steel-concrete composite shear walls have been widely studied and applied.However,the concrete composite shear wall with embedded steel(steel tubular)and the single steel plate concrete shear wall with embedded steel(steel tubular)have a complicated structure.The concrete distribution rebar at the location of shear wall need to be tied on site and the construction efficiency is low.Most of the current double-steel concrete shear walls with embedded steel(steel tubular)have exposed steel plates,which require professional fire protection and anti-corrosion treatment.This approach increases the construction cost.In this paper,the seismic performance and design methods of precast SRC composite tube shear wall with advantages of steel-concrete composite structure,confined concrete and dry-connected fabricated concrete structures is studied.The main contents of the study include:(1)Low-cycle load test of SRCT shear wall.The stress mechanism and failure process of SRCT shear wall are revealed.The low cyclic loading tests of 5 full-scale SRCT shear wall specimens and 1 full-scale RC shear wall specimen,has been carried out.and the cracks of each SRCT shear wall specimen are recorded and described in detail.The development trend and the failure modes of the test specimens are analyzed and summarized.And according to failure modes,the specimens are divided into three categories: A,B,C.Type A failure mode is mainly steel fracture and steel plate tear,and type C failure mode is mainly weld damage.And type B failure mode is between type A and type C.Type A is the ideal failure mode.During the loading process of the SRCT shear wall,the concrete and steel plates are subjected to a coordinated force.Each part of the material has a significant stress function and shows good overall stress performance.(2)Based on tests results,the seismic performance of each shear wall specimen is analyzed from comparing parameters such as steel plate thickness and spacing of piercing bars.The analyze is based on hysteresis curves,skeleton curves,displacement ductility,energy dissipation capacity,stiffness degradation,bearing capacity degradation.Experimental parameters such as steel plates thickness and spacing of piercing bars have different degrees of influence on seismic performance of the SRCT shear wall.Reasonable design and effective construction measures are required to ensure the full performance of the seismic performance of the SRCT shear wall.Compared with the RC shear wall specimen,The SRCT shear wall has higher bearing capacity,stronger energy dissipation capacity and lager lateral stiffness,and it shows good seismic performance.(3)Based on the theoretical method of Material Mechanics,the initial stiffness calculation model of the SRCT shear wall is established from the quasi-static test.The comparison with the experimental results shows that the calculation method can be well applied to the initial stiffness calculation of SRCT shear wall with 200 mm spacing of piercing bars.Limited by the number of test samples,further tests are needed to verify the applicability of this formula to SRCT shear walls with different piercing bars spacing.(4)Combined with the calculation theory of the bending capacity of eccentric compressed member,the simplified calculation model of bending capacity of SRCT shear wall has been established.The restraint effect of U-shaped steel and steel plates on inside concrete is considered in the calculation model.The calculation method of flexural bearing capacity of SRCT shear wall is proposed.By comparing with the test results,the accuracy of the calculation method is verified,indicating that the calculation method can be used in the calculation of the SRCT shear wall bending capacity.(5)Based on the analysis of tests data of SRCT shear wall,the calculation method of shear load capacity of SRCT shear wall is proposed and the calculation result is consistent with the test phenomenon.The calculation method refers to the relevant calculation methods of shear load capacity of shear wall in Code for Design of Composite Structures and Technical Regulations for Concrete Structures of High-Rise Buildings.Since the shear-span ratio of the test specimens is 1.6 and the failure mode of the shear wall is mainly bending failure,Therefore,the accuracy of the proposed method for calculating the shear capacity of oblique sections still needs to be verified by a series of tests on low shear-span ratio SRCT shear walls under horizontal load.Through the seismic performance test of the SRCT shear wall,the failure mode,bearing capacity,stiffness,deformation and energy dissipation capacity of the new shear wall were thoroughly analyzed,and the SRCT shear wall was verified better bearing capacity and seismic performance.By establishing a simplified analysis model of SRCT shear wall stiffness and bearing capacity,the theoretical calculation method of bearing capacity and stiffness of SRCT shear wall is proposed,which provides a reference and basis for the follow-up research and engineering application of SRCT shear wall. |
PDF Full Text Request