Limits of Application of Externally Bonded CFRP Repairs for Impact-Damaged Prestressed Concrete Girders

Abstract

Collisions between overheight vehicles and bridges are becoming more commonplace. Generally, collision damage is far from catastrophic, although sound repair techniques are critical if additional damage (typically related to corrosion) is to be mitigated. Although the decision to repair or replace a collision-damaged prestressed concrete structure must ultimately be made on a case-by-case basis, basic criteria for making this decision may be established. This paper describes parameters affecting the efficacy of external carbon fiber-reinforced polymer (CFRP) composite repair methods for restoring the flexural capacity of damaged prestressed concrete bridge girders. The study focuses on impact damage requiring structural repair (rather than simply aesthetic measures). The physical limitations of each CFRP repair method are described to define an initial design space, followed by a parametric study using two prestressed girder shapes (box and I-girder) and three CFRP repair techniques (externally bonded, prestressed, and near-surface mounted) in which the goal was to identify the design space of each technique. The effective design space for each method is then described by the spectra of damage to which the method may be effectively applied. The spectra of damage may be envisioned as having two thresholds: the no repair—repair threshold and the repair—replace threshold.