Flexural Performance of Steel Girders Retrofitted Using CFRP Materials

Abstract

There are many existing deteriorated steel bridges that need to be retrofitted. This paper investigates the effectiveness of using carbon fiber-reinforced (CFRP) composite systems in retrofitting deteriorated steel beams. A total of 13 medium-scale steel I-beams with a span of 1.6 m was tested in a four-point bending setup. The tested beams were divided into four groups according to their studied parameter. Group 1 consists of four unretrofitted beams with different percentages of artificial deterioration to simulate corrosion in the bottom flange with the aim to investigate their behavior and to determine the residual flexural capacity. The other three groups have deteriorated steel beams that were retrofitted with different CFRP systems with the aim to evaluate the effectiveness of the proposed retrofit schemes. Four deteriorated beams were retrofitted with CFRP sheets bonded to the tension flange and were tested in Group 2. Group 3 consists of two deteriorated steel beams that were retrofitted with CFRP plates externally bonded to the bottom flange of the tested beams. Group 4 consists of three beams retrofitted using an unbonded CFRP sheet attached to two ductile anchorage systems at the beams’ ends. The study shows that steel beams retrofitted with external bonded CFRP systems experienced limited ductility upon the failure of the CFRP either by debonding or rupture at higher load capacities than that of the unretrofitted beams. The proposed anchorage system could increase the strength of the deteriorated beam, behave in a ductile manner, and eliminate the early peel off of the CFRP sheet.