The Simplified Method Of Collapse-resistant Performance Evaluation Of Reinforced Concrete Frame Structures

The reinforced concrete(RC) frame structure has a large proportion in current structure forms, and its ability to resist collapse is an important indicator to ensure the safety of people’s life and property. A lot of existing reinforced concrete frame structures designed by the old codes, and factors such as durability and damage accumulation make the bearing capacity reduced. How to evaluate the collapse performance of structures reasonably has become a significant frontier topic. It’s essential to develop a set of indicators for the quantitative evaluation, so that the constructions which lack of seismic resistance capacity can be consolidated or even destroyed as early as possible. It should guarantee the request that no collapsing with strong earthquake. Considering the collapse resistance analysis generally needs to carry on the dynamic elastic-plastic time history analysis, which is time-consuming and complicate, it’s unrealistic for a large number of existing buildings. Therefore, this paper puts forward a simplified evaluation index of resistance to collapse based on incremental dynamic analysis method. The engineer can estimate the collapse-resistant performance of structures quantitatively only by simple calculation. The main research work and achievements are as follows:(1) Carry out the fragility analysis for the RC frame structure designed by current seismic code in degree 8 earthquake, and evaluate its collapse performance under the anticipative rare earthquake quantitatively. The results show that the RC frame designed by current seismic code has a little collapse probability under rare earthquake and provide a sufficient security for personal safety.(2) Compare the difference between fiber model and plastic hinge model on account of PERFORM-3D. It turned out that the structural response between them is similar and model difference has less influence on collapse performance evaluation. In consideration of convenience and reliability of the assessment, fiber model is a better choice.(3) Discuss the impact of “strong column weak beam” on the collapse performance, by adjustingc b?M/ ?M ratio to consider the inflection. Results indicate thatc b?M/ ?M ratio has a significant impact on collapse performance, and confirm the optimal ratio corresponding to the benchmark building.(4) Discuss the effect of “strong shear weak bending” on the collapse performance, by adjusting the space and configuration of hoop to change the parameterp uV/ V.The results indicate that variation ofp uV/ V also has a certain influence on collapse performance.(5) Analysis the correlation of the influence caused by the above two parameters on collapse performance evaluation. For the other buildings in degree 8 earthquake, the two parameters’ computation is simple. The engineer can conduct a quantitative evaluation of collapse performance referring to the existing research.