Blast testing of CFRP and SRP strengthened RC columns

Abstract

Blast testing on scaled reinforced concrete columns was conducted to study the behaviour of Steel Reinforced Polymer (SRP) wrapped columns in both flexure and shear. Two vertical testing frames were constructed to support each two columns per blast in a fixed-fixed configuration while applying a static axial load of 300 kN. The specimens were exposed to blast waves at a variety of incident pressures which resulted in damage from minor to severe. A reflected impulse which resulted in moderate damage was then selected and used to study the effects of varying the density of SRP wraps. CFRP strengthening was also used in order to compare the effects of the two strengthening materials. An SRP/CFRP hybrid combination using SRP for longitudinal or flexural strengthening and CFRP sheets for transverse or shear strengthening was tested. It was observed that the SRP strengthened columns were quite similar to those strengthened with CFRP. The experimental results were compared to both analytical SDOF models as well as numerical models created using advanced explicit analysis software. SRP appeared to be a very effective external strengthening material for increasing the resistance of concrete components, providing similar performance to other FRP (CFRP) wraps at potentially lower cost. The SRP materials proved to be quite resilient even when exposed to a close-proximity explosion where spalling of the RC columns was significantly reduced.