Abstract

This paper investigates various retrofitting schemes for a prestressed concrete box beam using carbon fiber reinforced polymer (CFRP) sheets with the goal of increasing flexural strength. A simply-supported box beam is studied with a constant uniformly distributed load and three gradually increasing concentrated loads proportional to HS20 truck loading of the Association of State Highway and Transportation Officials (AASHTO). Various retrofitting schemes are considered each with single, double, and triple CFRP sheets, respectively, installed in high compression and tension regions. Cross-sectional nonlinear moment-curvature relations are developed and coupled with a finite-difference solution algorithm to predict load-deflection relations for both retrofitted and non-retrofitted box beams. The study identifies effective CFRP retrofitting schemes that result in a significant increase in the flexural strength of the prestressed concrete box beam.