Static Load Test On Progressive Collapse Resistance Of Hollow Core Precast Concrete Slab With Special Detailing Connections

Masonry structure with precast hollow slab as floor slab(Cross-wall structure)is a building form with advantages of convenient,friendly to environment and low financial cost.This structural form is widespread in China,and its future development prospect is still very broad in rural and township areas.However,it is worth noting that when subject to accidental loads,such as gas explosion,cross-wall structure is very susceptible to progressive collapse due to the weak connection between precast slabs,thus threatening the safety of people’s lives and property.Therefore,it is of great significance to design reasonable and effective connections to ensure that effective ties can be generated between slabs after the failure of vertical load-bearing members,in order to resist the progressive collapse of the structure.In this thesis,five kinds of connections in hollow core precast concrete slab were designed and tested,and the bearing capacity,ultimate displacement and failure mode were analyzed in detail.Then,the test results were simulated by finite element software ABAQUS,then the influence of reinforcement strength,number of connectors and slab span on the bearing capacity was analyzed.Finally,the energy dissipation capacity and equivalent dynamic bearing capacity of each specimen were analyzed.The main contents are as follows:(1)Based on the tie method,five kinds of precast slab connections were designed considering strength and ductility requirements,a typical sub-structure of the cross-wall structure after the failure of the vertical bearing wall was extracted as the experimental specimen.Progressive collapse resistance was studied through quasi-static test,which can be the foundation of the subsequent test result analysis and finite element analysis.(2)Test results were analyzed in detail,including load displacement curve,development of strain and crack,and failure modes,then the stiffness of the loading device was calculated.Based on the analysis,the performance and load transfer mechanism of each specimen against progressive colapse was studied.(3)The three-dimension finite element models of each specimen were established using ABAQUS,and the results are basically consistent with the test results.After that,the effects of reinforcement strength,number of connectors and the span of precast slab on the mechanical performance of the structure were analysised.(4)Based on energy balance principle,the energy dissipation capacity of five specimens was evaluated,and the equivalent dynamic strength of the specimens was calculated by the capacity curve method to further evaluate the progressive collapse resistance of the structure.Finally,the cracking moment of the specimen under negative moment was calculated based on the plane section assumption and force balance,and the composition of resistance capacity of the specimens was analyzed.