Experimental study on progressive collapse mechanism of reinforced concrete sub-assemblage with two-span beams under blast loading
To investigate the progressive collapse mechanism of reinforced concrete(RC)sub-structure with double-span beams under blast loading,three vertical impact tests on middle-joint of the RC substructures with double-span beams are carried out,which is aimed to consider the axial tension effect on the remaining sub-structure from the bearing column in failed process under blast loading.The results showed that,at the moment of loading,an obvious reverse arch action appeared in beam due to inertial effect,compressive arch action appeared with decrease of inertial effect and increase of middle joint displacement.Under the impact condition in test,no fracture occurred in the longitudinal bars.The damage mode of beam exhibited a flexural damage at the beam ends.Continuous longitudinal bars at the top of the beam can mitigate the crack development in beam span,and reduce the peak displacement of middle joint in dynamic response of substructure.