Study On Aseismic Behavior And Damage Evaluation Of HRBF500 RC Column Based On Unloading

At present,the research of HRBF500 RC structure is in its initial stage. There was some progress in the field of material properties,simply supported beam and Bond properties. Based the status,the seismic performance of HRBF 500 RC column and its damage status in the earthquake were studied in terms of unloading effects of yield systems and energy conversion. Simultaneously,the method of evaluation which was based on energy conversion was presented.Based on its quasi-static test,HRBF500 RC columns'capacity of energy dissipation was studied in terms of unloading effects and energy conversion. By analyzing effects of plastic development , capacity degradation and time,the trend of HRBF500 RC columns'capacity of energy dissipation was found to be similar with common RC columns'. Energy ductility index was defined from the respect of energy conversion. The seismic performance of columns was evaluated using this new energy ductility index.The degradation of columns'strength and stiffness was analyzing with phenomena of test. The theoretical skeleton curve of HRBF500 RC column was presented to change the status that there is not appropriate restoring force model for HRBF500 RC column. Key points in various stages were determined by theoretical or experimental methods,including unloading stiffness and hysteretic rules.Two progresses in the research of damage in the earthquake were achieved to be able to understand the damage development of columns during the earthquake and provide information for seismic design based damage performance. On the one hand,amended Park damage model was presented,including its damage evaluation law,the other hand,a new damage model based on elastic energy loss was presented,which considered unloading effects of yield systems and energy conversion. Simultaneously,its new damage evaluation law was presented and its rationality and availability was proved by the test.The nonlinear dynamic analysis of HRBF500 RC framework was achieved by IDRAC 2D. Dynamic responses and damage status were recorded and analyzed to show that HRBF500 RC framework with seismic design can resist earthquake effectively. The damage index of stories and global structure could be calculated reasonably by weighting coefficient and period snapshots. The amended Park damage model could be better used in the whole process of nonlinear dynamic damage analysis,which shows well effect in practice.