Repair methods for prestressed girder bridges.

It is common practice that aging and structurally damaged prestressed concrete bridge members are taken out of service and replaced.This, however, is not an efficient use of materials and resources since the member can often be repaired in situ. There are numerousrepair techniques proposed by entrepreneurial and academic institutions which restore prestressed concrete girder flexural strength andsave both material and economic resources. Of course, not all repair methods are applicable in every situation and thus each must beassessed based on girder geometry and the objectives of the repair scenario. This document focuses on the practical application ofprestressed concrete bridge girder repair methods.In this document, repair methods are presented for three prototype prestressed concrete highway bridge girder shapes: adjacent boxes(AB), spread boxes (SB), and AASHTO-type I-girders (IB), having four different damage levels. A total of 22 prototype repair designsare presented. Although not applicable to all structure types or all damage levels, the repair techniques covered include the use ofcarbon fiber reinforced polymer (CFRP) strips, CFRP fabric, near-surface mounted (NSM) CFRP, prestressed CFRP, post-tensionedCFRP, strand splicing and external steel post-tensioning. It is the authors\u2019 contention that each potential structural repair scenarioshould be assessed independently to determine which repair approach is best suited to the unique conditions of a specific project.Therefore, no broad classifications have been presented directly linking damage level (or a range of damage) to specific repair types.Nonetheless, it is concluded that when 25% of the strands in a girder no longer contribute to its capacity, girder replacement is a moreappropriate solution. Guidance with respect to inspection and assessment of damage to prestressed concrete highway bridge girdersand the selection of a repair method is presented. These methods are described through 22 detailed design examples. Based on theseexamples, review of existing projects and other available data, a detailed review of selection and performance criteria for prestressedconcrete repair methods is provided.Best practices based on the study objectives are presented