HYDROCARBON POOL FIRE PERFORMANCE OF FIBER REINFORCED POLYMER (FRP) STRENGTHENED AND THERMALLY INSULATED BRIDGE GIRDERS

Abstract

Highway bridges encounter various extreme load hazards, such as earthquake, flood, blast, collision, wind and fire during their design lives. The effect of accidental, natural or man-made fire on bridges is one of the least investigated which may be due to the assumption that bridge fire has a low probability of occurrence. However, a bridge failure survey showed that fire had caused more bridge collapse in the USA than earthquakes. The main objective of the current research is to study concrete bridges in general, and fiber reinforced polymer (FRP) strengthened bridge girders in particular against fire hazard. The research is divided into three distinct phases. The first phase involved building the bridge, loading the bridge with the simulated HL-93 live load and finally subjecting it to hydrocarbon fire. The superstructure of the tested bridge comprised of three Texas standard girders, precast deck panels, and cast-in-place deck. One girder was wrapped with carbon fiber reinforced polymer (CFRP), another with CFRP and sprayed with fireproofing and third was a control girder without CFRP or fireproofing. The second phase involved saw cutting the deck, transporting the girders to the CELAB and performing residual strength test. The third phase dealt with numerical modeling of the test bridge under fire to verify the experimental phase. It was found out that the insulation successfully preserved the integrity of the FRP strengthening, the underlying concrete, and the prestressing strands. On the contrary, the girder without insulation sustained severe damage and lost a significant amount of its flexural load carrying capacity.