Behavior of RC beam-slab system under corner column failure scenario

This is the Phase I of the two phase experimental investigation of older reinforced concrete beam-slab system uder column removal scenario. In phase I tests were performed on a 1/3rd scale 2x2 panel beam-slab system with spandrel beam on two edges. This specimen models a portion of a floor system encountered in older reinforced concrete buildings, constructed before the introduction of seismic design provisions. Column failure tests were conducted at three corner support locations to study the behavior of the floor under a column failure scenario, with particular interest in understanding its ability to redistribute the loads to adjacent support locations.

The specimen was support on five custom built multi-axis load cells and four axial load cells to monitor the loads transferred to each support location during the tests. Before the column removal tests, uniform gravity load of 90psf was applied to the specimen in two stages using concrete blocks, followed by three pattern loads. Following the end of gravity load tests, quasi-static column removal tests were performed at the three corner locations using vertical actuators.

For all column removal tests, the specimen performance was satisfactory based on its load carrying capacity and post-yield behavior. For all the tests, the damage conformed to the Yield Line Theory, but the load capacities were about 1.5 times higher than the YLT estimates. In particular, significant load enhancement was observed when spandrel beams were present, due to the large compression generated in the beams. Physical damage to the slab was primarily concentrated between the test location and yield line, with the remainder of the slab experiencing little to no damage.

Phase I: Corner Columns
1.1% longitudinal reinforcement ratio - Beam
0.67% transverse reinforcement ratio - Beam
0.5-0.9% longitudinal reinforcement ratio - Slab
60 ksi longitudinal steel - Beam
40 ksi transverse steel - Beam
40 ksi longitudinal steel - Slab
6400 psi concrete
Trial_1: Uniform gravity of 38 psf
Trial_2: Uniform gravity of 90 psf
Trial_3: Pattern Load of alternate 38 and 90 psf
Trial_4: Column removal at beam-beam corner
Trial_5: Column removal at slab-slab corner
Trial_6: Column removal at beam-slab corner