Impact on Reinforced Concrete Structures

This entry covers impact effect on reinforced concrete structures. It begins with an overview of the types of impact actions concerned and the characteristic response and damage patterns of reinforced concrete structures. A brief discussion on the hard and soft impact and the corresponding impact loads follows. As generally understood, the response of reinforced concrete structures subjected to impact involves broadly three levels of dynamic processes, namely, (i) concentrated local effect such as penetration and perforation; (ii) extended local effect due to punching shear and shear plugging, which may be regarded as an intermediate phase between the local and global structural effects; and (iii) the overall structural response. Considering that the overall structural response is largely a classical structural dynamics problem, the impact analysis here focuses on the local and the intermediate effects. Thus, the punching shear and shear plugging is discussed first, followed by the penetration and perforation of reinforced concrete targets due to hard projectile impact. The strain-rate effects on the reinforced concrete materials are discussed in terms of the classical dynamic increase factors (DIFs). Results from the more recent studies concerning the inertial confinement effect on the dynamic compressive strength of concrete are also discussed, and the implication on an appropriate use of a DIF at the material property level is highlighted. Finally, typical numerical modelling frameworks for the simulation of the impact response of reinforced structures are briefly introduced and discussed.