9413857 Saadatmanesh This project will demonstrate experimentally and analytically the feasibility of strengthening and retrofitting steel girders in composite steel concrete bridges with epoxy bonded carbon fiber laminates. For upgrading the flexural capacity, carbon fiber plates or tapes are epoxy bonded to the girder tension flange. For retrofitting, this material is epoxy bonded to the girder tension flange which contains pre-existing fatigue cracks. Three beams will be tested under static loading to determine the flexural strength of a composite section of concrete deck, steel girder, carbon fiber tape, and epoxy. This includes strengthening in the positive and negative moment regions. Five sets of beam fatigue tests will be investigated for a section of steel girder, carbon fiber tape, and epoxy. This includes investigation of: Fatigue strength in the positive moment region with pre-existing fatigue cracks; fatigue strength as a function of applied stress range; classification of fatigue strength according to the AASHTO's Standard Categories; and the ability of retrofit to arrest fatigue crack growth. This project is a joint effort between the University of Arizona and the Worcester Polytechnic Institute. All full-scale tests will be conducted at the University of Arizona. The coupon tests will be performed at the Worcester Polytechnic Institute. The analysis of results and development of guidelines and methodology for application of this technique will be performed by the investigators at both institutions. ***
