Study On The Seismic Performance And Failure Mechanism Of Infilled RC Frames

Reinforced concrete infilled-frame structure are recognized as amongst the most common structural forms of buildings in the world.Although this structural form has been adopted for buildings for many years,the codes for designing it could not yet take the disadvantages the infilled walls might brought into consideration.Especially with the recommendation of using new-type building blocks,the research of the seismic behavior and failure mechanism of the infilled-frame structures is urgently needed.An experimental study on the seismic performance of aerated concrete blocks(ACB)constrained by steel frame,as well as the FEM analysis of various infilled-frame structures was conducted.The key contents of this dissertation are as follows:(1)A pier of ACB infill constrained by hinged steel frame was tested with horizontal in-plane cyclic loadings.The result of this test was compared with the results of the infills constrained by RC frames,and there are similarities and differences between them.The cause of the result of this test was revealed that the shear strength of the mortar was weaker than expected.(2)A discrete modelling approach for infilled RC frame structures was developed and then verified with the introduction of damage-based cohesive traction-separation law to simulate the crack propagation,post-fractured behavior and finite sliding and separation of the infill wall.(3)The finite analysis of a one-story two-bay structure with different arrangement of infills and different shear strength of mortar was performed to analyze the crack pattern and failure mechanism of infilled structures with various kinds of mortars.(4)The finite analysis of a single-story and single-bay frame with different arrangement of openings under horizontal monotonic loading was completed.The propagation of the force-transferring and crack pattern of the infills as well as theinfill-frame interaction under different stages of the failure was discussed.