| Reinforced concrete structures rely on concrete and steel work together to support external loads. Compared to the static load, the mechanical properties of concrete and steel have significant changes on the dynamic load. These changes have led to the dynamic performance of the structure change. It is easy to find earthquake damage tend to occur in the joints area, so the frame structure beam-column joints is an important part of the main structure. At present the research on the dynamic performance of the reinforced concrete beam-column joints is rare. Also these studies focused mainly on the impact load and explosive load, and there is nearly no study about strain rate effect on reinforced concrete structures under the seismic loading. In this paper, using the methods of theoretical analysis, experimental investigation and numerical simulation, the effect of strain rates on the reinforced concrete beam-column joints is studied. The main contents of this paper are as follows:(1) By experimental means, the influence of loading rates on the dynamic performance of the concrete is studied. According to the results, the expression of DIF (Dynamic Increase Factor) of the compressive strength of concrete is fitted out.(2) By experimental means, the influence of loading rates on the dynamic performance of the steel bar is studied. According to the results, the expressions of DIF (Dynamic Increase Factor) of the yield strength and tensile strength of the steel bar are fitted out.(3) By experimental means, the influence of loading rates on the dynamic performance of the reinforced concrete beam-column joints is studied.The impact of loading rates on the failure modes, yield strength, ultimate strength, ductility factor is analyzed.(4) Based on the nonlinear finite element program ANSYS, dynamic responses of reinforced concrete beam-column joints under different loading rates are analyzed to simulate the dynamic test at different loading rates. |
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