The Experimental Researches On Seismic Behavior Of Frame Side Joint In Steel High-strength Reinforced Concrete

With the development of the modern buildings and the increasing in height and span of the buildings, reinforced concrete structure (RC) has been incompetent for the change. Despite the characteristic of increasing bearing capacity of member, reducing of sectional dimension of high strength reinforced concrete (HRC) structure, it is not in disregard of disadvantage of high strength concrete that has the character of bad ductility and great friability. Steel high-strength reinforced concrete (HSRC) structure, which is the new type of structure, is formed by steel encased in reinforced high strength concrete structure. That steel and high strength concrete can interact it each other is contributed to the improvement of strength of steel and high strength concrete respective in HSRC structure and the amelioration of the character of bad ductility and great friability of high strength concrete. Therefore, HSRC structure has great development potential and development space. Although a lot of researches on the seismic behavior of steel reinforced concrete (SRC) both at home and abroad have been made, studies on HSRC structure are not enough. Based on this, the experimental study on seismic behavior of frame side joint in steel high-strength reinforced concrete structure is presented.The experimental research of 9 HSRC frame side joints under the cyclic reversed loading have been carried out in this thesis. After that, based on the results of the tests, the process of load bearing and failure mechanism are studied. The seismic behavior of the HSRC frame side joint is analyzed. And the evaluation that affects the seismic behaviors by axial compression ratio has been discussed. At the same time, the ductility and the energy dissipation capacity have been studied. The strains of steel, stirrup and reinforcement of the columns and beams in the joints core are analyzed.By the tests of 9 HSRC frame side joints under the cyclic reversed loading. It is found that the design of"dog-bone"connections can transfer the yielding joint from flange welds to parent metal zone, which possesses better plasticity and avoid yielding joints in weak welds. This design also enables beam flanges to dissipate earthquake energy and protects weak welds. Under an equal or close by circumstance in the axial compression ratio, the seismic performance, including the ductility and energy dissipation capacity of the HSRC-B joint with dog-bone type weakening is clearly superior to that of the ordinary HSRC-A joint. Therefore, dog-bone exterior joints of the integrally fabricated HSRC frame may improve seismic behavior.The theoretic analysis of the HSRC frame side joint is presented. According to the experimental data, a calculating formula of crack resistance of the HSRC joint is derived. The results indicate that the calculations agree well with those obtained on test. After that, a practical formula of shear capacity of such joint is deduced. And the experimental data are compared with the data calculated by the recommended formulas. Finally, some valuable conclusions have been gained.