Evaluation of the inertia force in compressive impact loading on steel fiber-reinforced concrete

Abstract

Steel-fibre-reinforced concrete (SFRC) is a strain rate sensitive material and, therefore, its dynamic and static compressive behaviour can be significantly different. In the present study, the effect of loading rate on the compressive behaviour of SFRC with 1% hooked end steel fibres is experimentally investigated. During impact loading, an inertia force is created due to acceleration along the specimen, whose effect in the range of impact is studied for a comprehensive assessment of the dynamic analysis of SFRC structures. For the evaluation of the inertia force, an instrumented drop-weight test setup is used, which includes two fast response loadcells with capacities of 1000 and 2000 kN on top (impact force) and bottom (reaction force) of specimen. The drop-weight impact tests were performed with three different drop heights, corresponding to maximum strain rates that ranged from 1 to 50 s−1. Two high-capacity accelerometers (5000 g) were mounted in the middle of the cylindrical specimens to obtain the cylinder acceleration response. The results show that, by increasing the strain rates, compressive strength, maximum acceleration at the middle of cylinder, and inertia force are increased. The results in terms of the ratio between inertia and impact load of specimens are presented and discussed.