Numerical Evaluation of Reinforced Concrete Columns Retrofitted with FRP for Blast Mitigation

Abstract

Fiber reinforced polymer (FRP) material is commonly applied in retrofitting structures due to the advantages of high strength and well corrosion resistance. Previous studies indicated that retrofitting with FRP sheet was an effective way for protecting the existing structures to resist the blast loads, but little research made comprehensive comparison study on the blast response of RC columns with different retrofitting strategies. This paper proposed a series of FRP retrofitting strategies and evaluated their effect on blast mitigation using numerical analysis approach. Comparison studies were conducted on the effect of FRP type, FRP thickness, and retrofitting mode on blast mitigation. A finite element model of RC columns retrofitted with FRP under blast loading was developed. The model considered the strain rate effect of steel and concrete and the orthotropic property of FRP composites. The reliability of the proposed model was validated against the data from a field blast test. Based on the verified model, the blast responses of RC columns with different retrofitting strategies were numerically investigated. According to the result analysis, appropriate FRP type, FRP thickness, retrofitting mode, and retrofitting length were recommended.

Numerical investigation on CFRP strengthening and reinforcement bar detailing of RC columns to resist blast load

“…FEA simulations revealed a result that CFRP strengthening could be an optimal and effective solution to mitigate the damage associated by the blast induced shock waves. Moreover, Zhang et al [21] and Zhao et al [22] conducted a numerical investigation on methods of enhancing capacity of RC column. Zhang et al [21] performed a novel work to determine the effect of axial compression ratio, torsional-bending ratio, and eccentricity on the load carrying capacity of RC column strengthened by high performance ferrocement Laminate (HPFL)-bonded steel plates (BSP) prone to combined loading cases.…”

“…The authors reported, all damage strengthened specimens under combined loading cases exhibited increase in load carrying capacity of specimen whereas energy absorption capacity and ductility ratios were reduced significantly. Zhao et al [22] developed a numerical model to investigate the behavior of RC columns retrofitted with various FRPs composites such as CFRP, GFRP, and AFRP as external jacketing material for RC columns under blast loads. The authors reported among the three FRP types, CFRP performed well in enhancing blast resistance capacity of RC column.…”