I-345 Bridge Repair

Starting early 1990s, fatigue cracks were found to have developed at many floorbeam to girder connections of the I-345 Bridges. The bridges were designed with a special framing and support system, which caused cracks to develop at various welded details. Part of the bridges was previously repaired, but cracks continued to grow, and in some cases occurred again at the repaired details. A new retrofit plan was therefore developed recently by the Texas Department of Transportation, Bridge Division, through a combined research effort with the University of Texas at Austin, Ferguson Structural Engineering Laboratory. This paper discusses the authors' experience obtained through the repair of the I-345 Bridges, including lessons learned from the previous repairs, development of the new repair strategy, findings obtained from the field test and finite element analysis, and recommendations for future work. The repair construction is current underway and scheduled to be completed by June 2010.