Design Of Novel RC Frames Considering Earthquake And Progressive Collapse

Study on multi-hazard prevention and mitigation of building structures is the latest developing trend in civil engineering.Reinforced concrete(RC)frames,one of the most widely used structural systems in engineering practice is chosen as the research object in this study.The research focuses on integrated hazard prevention of RC frames against both earthquake and progressive collapse.The main work of this study includes:(1)The seismic and progressive collapse performance of an RC frame is evaluated through vulnerability analysis method.Effects of the seismic design and progressive collapse design on the overall performance of the structure are studied.(2)Experimental studies on the substructures of a conventional RC frame(RC6),an RC frame after the progressive collapse design(RD1)and an RC frame adopting the newly proposed structural detailing(RD2)are conducted to evaluate their seismic and progressive collapse performance.The results indicate that current progressive collapse design can effectively increase the progressive collapse resistance of RC structures.However,after implementing the progressive collapse design,the component damage migrates from the beams to the columns during the seismic cyclic tests,which also results in severe damage on the columns and joints of RD1 specimen.Through adopting the proposed structural detailing,the damage caused by the newly added anti-progressive collapse reinforcement can be notably mitigated while improving the structural progressive collapse resistance.Based on the experimental studies,the modeling techniques and corresponding FE models in OpenSees are proposed to simulate the seismic cyclic tests and progressive collapse tests with a good agreement,proving the feasibility of the proposed models.(3)Experimental studies on the substructure of the newly proposed multi-hazard resistant prefabricated concrete frame(MHRPC frame)are conducted.The seismic cyclic tests reveal that the MHRPC specimen has much smaller residual deformations and lower component damage compared to the RC specimens.Following a simple repair,the MHRPC specimen can recover and maintain a stable seismic performance,which satisfies the demand of resilience.In the progressive collapse test,the MHRPC specimen has a much higher progressive collapse resistance than the RC specimens.Moreover,the MHRPC specimen meets the requirement of the chord rotational capacity as regulated in the design codes,demonstrating a superior progressive collapse resistance.Similiarly,the modeling techniques and FE models of MHRPC sbustructures are also proposed and validated with the experimental results in OpenSees.(4)An explicit and practical analytical method is proposed to calculate the compressive arch action(CAA)in RC beams both with and without slabs.Compared to the existing models,the slab effect is included in the proposed model.In addition,the proposed model is able to calculate the CAA resistance of RC beams and beam-slab substructures based solely on their geometric and reinforcement information.(5)Based on the experimental results,the major load carrying components and deformation modes of the MHRPC specimens are identified.The computational models for calculating the load carrying capacities of the specimens in the seismic cyclic tests and progressive collapse test are proposed.The backbone curves derived from seismic cyclic tests and the load-displacement curve of the progressive collapse test are calculated and compared to the experimental results with good agreements.The proposed model could provide a reference for the design of the newly proposed MHRPC frame system.