Effects of Reinforcement Discontinuity on the Collapse Behavior of Reinforced Concrete Beam-Slab Structures Subjected to Column Removal

Existing reinforced concrete buildings constructed in low-seismic zones are most vulnerable to disproportionate collapse due to low reserve strength and presence of reinforcement discontinuity. This research aims to experimentally observe the collapse behavior of such ordinary structures, particularly the beneficial development of compressive arch and catenary actions, and evaluate the effects of various reinforcement detailing on building collapse resistance. Three $1/3$-scale beam-slab-column assemblies representing parts of a prototype building structure were monotonically loaded until complete failure through a 12-point loading system simulating uniformly distributed loads. The test units with beam and slab longitudinal reinforcement discontinuity exhibited relatively ductile collapse modes with a beam chord rotation angle of 12%. Catenary action developed well in beam and slab top reinforcement, whereas the mobilization of compressive arch action was insignificant. Providing longitudinal reinforcement continuity could increase both load and deformation capacities of test structures up to 160% and 140%, respectively. The yield-line approach can conservatively predict the collapse load of beam-slab structures and can be used as a simple but reliable check for the potential collapse.