Influences on the structural response of beams in drop tower experiments

Drop tower tests on beam specimens were carried out to evaluate the influence of different geometric features and different loading velocities on the beams' response. Tested geometric characteristics are stirrup reinforcement in addition to longitudinal reinforcement, and notches. The goal is to quantify the differences in the global behavior and the amount of strains and strain rates measured at different positions on the reinforcement. This gives an insight into strain distributions along the rebars from which bond stresses can be derived. It can be stated that stirrup reinforcement kept the specimens together and thus increased the impact resistance. That was seen in the deflection and acceleration measurements, but it was also suggested by strain measurements, especially looking at residual strains. The maximum strains are generally more affected by global bending of the specimens than by the formation of a localized punching cone, which was the main failure mode.