Behavior of reinforced concrete slabs subjeted to impact loads

Abstract

This study presents the findings of an experimental program designed for investigating the behavior of RC slabs under low-velocity impact loads. Six RC slabs with dimensions 2015x2015x150 mm were tested at the Structural Laboratory of the Izmir Institute of Technology. To facilitate a comparison between the static and impact behavior of identical specimens, the slabs were cast in three identical pairs, such that one of the specimens was tested under impact loads whereas its identical twin was tested under static loads. To test the slabs under simply supported conditions, an innovative impact test setup was designed and manufactured, supporting the specimens at 20 locations along the perimeter and holding the specimens in place during the impact induced rebound. This setup was also used for the testing of the specimens under monotonically increasing static loads at the midpoint. Impact loads were induced on the specimens by a free falling drop-weight, impacting the specimens at the midpoint. The specimens were intensely instrumented with 20 load cells at each support location, 24 displacement transducers, 6 accelerometers and 12 strain gauges fixed to the reinforcing bars. Dynamic data was captured with the help of a high speed data acquisition system, capturing and recording the data at a rate of 250 kHz per channel. The results obtained from these tests revealed that the impact behavior of slabs differs significantly compared to their static behavior. Displacement profiles and force distributions are highly affected due to the high inertia forces during the impact.