Flexural Performance of Carbon Fiber-Reinforced Polymer Prestressed Concrete Side-by-Side Box Beam Bridge

Abstract

The effect of varying transverse posttensioning levels and arrangements on the load response of a one-half scale 30° skewed seven box beam bridge model was investigated. The effective span of the bridge model was 9.45 m (31 ft) with a width of 3.35 m (11 ft) and depth of 355.6 mm (14 in.). The bridge model was prestressed and reinforced with carbon fiber composite cables (CFCCs). CFCCs were also used as shear reinforcement. The bridge model was provided with five transverse diaphragms equally spaced along the length of the bridge. The experimental investigation included load and strain distribution tests and a flexural ultimate load test. The load and strain distribution tests were conducted on the bridge model with and without full-depth longitudinal cracks at the shear-key locations. The investigation showed that the application of an adequate transverse posttensioning force was successful in restoring the load distribution of the bridge model with full-depth longitudinal deck cracks to that of the case without deck cracks. The ultimate load and the associated compression-controlled failure mode of the bridge model agreed well with that predicted according to ACI 440.4R-04 and numerical analysis. The behavior of the bonded pretensioned and reinforced CFCC strands was linear elastic and remained intact throughout the collapse of the bridge model. The unbonded transverse posttensioned CFCC strand also remained intact.