Experimental investigation of slender RC columns under horizontal static and impact loads

Abstract This paper reports an experimental investigation on the behaviour of slender reinforced concrete (RC) columns under horizontal static or impact loading. Fourteen square RC columns were tested under horizontal impact loading by using a modern horizontal impact facility. These specimens were subjected to the same design impact velocity of 0.8 m/s. The effects of three main parameters, namely the specimen slenderness ratio, the longitudinal reinforcement ratio, and the axial compression ratio, were considered. Based on the impact test results, the descriptions of failure mode, crack pattern, time histories of impact force, deflection, and strain are illustrated. On the other hand, tests on three additional RC columns with different cross-section dimensions subjected to horizontal static loading were undertaken for comparison purpose. In the comparisons of the load–displacement relationships for static and impact load cases, the significant divergence can be observed owing to the existence of the inertial force initiated in the dynamic responses. After the completion of the impact test, six impact-damaged specimens were tested under static loading to evaluate their residual resistance and the corresponding behaviour. It is found that the ultimate capacities of damaged specimens could reduce by 7%–14% compared with those of undamaged ones.