Seismic Behavior Of Embedded Steel Plate Reinforced C80 Concrete Composite Shear Walls

Recently, high-rise buildings are developing very rapidly in China. A variety of high-rise and super high-rise buildings continually spring up. Due to the advantages of higher load carrying capacity, better ductility and energy dissipation capacity, Embedded Steel Plate Reinforced Concrete Composite Shear Walls(ESPRCCSW) meet the higher requirement of such high-rise buildings both in terms of strength and stiffness as structural members. At the same time, employment of high strength concrete can bring about the benefits such as saving materials, reducing section size of structural members and increasing architectural space, therefore it is becoming an optimal material in the field of high-rise buildings. By integrating high strength concrete into ESPRCCSW,the advantages of both steel and high strength concrete can be effectively taken of to increase the load carrying capacity and lateral stiffness, while section size of shear walls can be effectively reduced, and the overall seismic performance of buildings can be enhanced. However, due to lack of research findings and engineering practice, the application of high strength concrete ESPRCCSW is very limitedBy experimental study and theoretical analysis, this thesis investigated the seismic performance of ESPRCCSW members with concrete grade of C80 under reversed cyclic loading. The objectives of the thesis were to examine the load carrying capacity, stiffness, ductility, energy dissipation capapcity and failure mechnism of high strength concrete ESPRCCSW. On the basis of experimental and analytical results, design provisions were proposed for ESPRCCSW. The thesis had specifically accomplished the following contents:(1)A total of 30 ESPRCCSW specimens had been tested,in which 20 have the shear span ratio of 1,and the rest 10 have the shear span ratio of 2 respectively. Systematic analysis had been carried out on the influence of axial compression ratio, steel plate ratio, rebar spacing and reinforcement ratio on the load carrying capacity, stiffness, deformation capacity, energy dissipation capacity and failure mechanisms of the members. The research findings revealed that steel plates can effectively increase the load carrying capacity, lateral stiffness and energy dissipation capacity of ESPRCCSW; the design axial compression ratio limit for ESPRCCSW may be taken as 0.50; high strength concrete of C80 can be used in ESPRCCSW members without influencing the required deformation capacity, if certain detailing measures are ensured,.(2)Nonlinear finite element analysis had been performed for ESPRCCSW by VT2 program based on the modified compression field theory, on the level of stress-strain relationships of materials to unveil the damage process and failure mechanism of ESPRCCSW under reversed cyclic loading conditions to simulate the earthquake action. The numerical results were compared with the experimental results. From the comparison it is found that the FE simulation has relatively high accuracy. The load-displacement curves obtained by VT2 simulation agree well with the recorded measured curves; failure positions and patterns under compression/tension and crack propagation of the FE model are also similar to the experimental results.(3)By analyzing the contribution of steel plates to the ultimate shear carried by the shear wall, and by revising the coefficients for steel profiles and steel plates in the existing equation in the current code of practice, a new calculation equation was proposed for the ultimate shear design of ESPRCCSW. The equation can better reflect the effect of steel plate ratio on the ultimate shear of the shear wall. By analyzing experimental data,it was found that the assumption of plain sections remain plain is applicable to ESPRCCSW with high strength concrete of C80.