Analytical evaluation of frp-retrofitted concrete structure considering debonding failure under blast loading

Even though FRP (Fiber Reinforced Polymer) has been widely applied to the retrofitting materials, the behavior of FRP to blast load, an impulsive load with extremely short time duration with very high pressure, has not been accurately examined closely. From presently established studies in the behavior of FRP, most studies have focused on the performance of FRPretrofitted structures by making simplifications in modeling, without accurately applying the physical characteristics and failure mechanism of FRP. If the effect of these characteristics and mechanism are not accurately studied, the retrofit design and performance evaluation of FRPretrofitted concrete structures may become inaccurate. Therefore, it is critical to establish an analytical model that can properly consider the features of FRP retrofitting in evaluating the response of concrete structures under blast loading. In this study, analysis technique for FRP retrofitted concrete structures under blast loading is suggested by considering FRP material characteristics and failure mechanism in modeling. Based on resilient blast retrofit design concept, the developed method is composed of rate-dependent FRP failure model considering strain-rate effect and debonding failure model between FRP and concrete using contact element implementation. In rate-dependent FRP failure model, strain-rate effect is considered from the past reported studies. From the comparative verification, the proposed analytical evaluation is able to predict the behaviors such as rate-dependent failure mechanism and debonding failure expressed by contact formulation of FRP.