Dynamic Response of RC Slab Under Drop Test Retrofitted with CFRP Strips Using NSM Technique

Abstract

Slabs are two-dimensional structural elements in a storied building that provide large useful area for working during construction and even after occupancy. The effect of impact loads on slabs was not studied effectively due to lot of constraints, like lack of experimental setup, cost of sophisticated equipment, boundary conditions and so on. Drop test on slabs is gaining importance in recent years due to its simplicity in experimental setup while measuring the dynamic response of slabs under impact loads with a reasonable degree of accuracy. An experimental investigation was conducted on simply supported two-way RC slab under three drop heights to study the variation in the dynamic response of strengthened slab by near-surface mounting (NSM) technique over normal RC slabs. The dynamic response was studied over different height of impact and change in concrete grade, and the effect of strengthening was recorded using an accelerometer mounted at the bottom of slab. All the slabs were tested as simply supported with the drop weight impacting at the centre of the slab on the top surface. It was observed from this experimental result that the height of the drop and strengthening technique influence the dynamic behaviour of RC slab. Peak displacement, acceleration and damage index in terms of energy required per unit length of crack were compared to demonstrate change in the dynamic behaviour of RC slabs. It was interesting to note that the sudden change in the response of RC slabs over the different kinetic energy needs further detailed investigations.