| Concentrically-Braced Frame(CBF)structure consists of two lateral force systems,a low-ductility bracing system and a frame system.This type of structure does not consider seismic structural design by increasing the design bearing capacity.The support system has low ductility and is prone to brittle failure when subjected to earthquakes.However,studies have shown that after the support failure of a reasonably designed CBF structure,the remaining part can serve as a reserve system to continue to bear the seismic effect and has good collapse resistance Compared with ordinary steel structure buildings,the construction cost is lower,and it is suitable for popularization and application in low-and medium-intensity seismic fortification areas in China.How to reasonably evaluate the seismic performance of the structure and quantify the collapse resistance of the structure reserve system is of great significance to the design and application of such structures.In response to the above problems,this article has carried out the following research:(1)Based on the incremental dynamic analysis method,quantify the collapse resistance of the low-ductility concentrically-braced frame structure under different design parameters,calculate the vulnerability of the low-ductility CBF structure under different parameter conditions,and analyze the reserve bearing capacity and reserve The influence of design parameters such as stiffness,structure period and strength reduction factor on the collapse resistance of low ductility structures.(2)According to the calculation results,a calculation formula for the collapse of the low ductility CBF structure under different parameters is established,and a simplified evaluation method for the collapse resistance performance of the CBF structure based on the formula is proposed.The numerical example verifies the method Applicability and accuracy.(3)A quantitative evaluation method for the anti-collapse performance of the multi-storey concentrically-braced frame is proposed.The results of the finite element analysis method are compared with the quantitative evaluation method.The results show that the calculation results of the anti-collapse quantitative evaluation are more accurate and can meet the actual engineering needs.The evaluation and design of the project has guiding significance. |
