Performance of an AASHTO Beam Bridge Prestressed with CFRP Tendons

Abstract

Corrosion-induced deterioration of steel RC highway bridges is one of the major distress types that can render a structurally deficient bridge before reaching the design life. One feasible solution to the problem is to replace the conventional steel reinforcement with noncorrosive carbon fiber–reinforced polymer (CFRP) reinforcements. However, the CFRP reinforcement as an internal reinforcement has not been explored in AASHTO-type prestressed concrete beam bridges. AASHTO-type beams have an I-type cross section with a bottom flange, and on integration of the deck slab, the final shape is a bulb-T section. This paper discusses the experimental investigation of a precast prestressed AASHTO control beam and a bridge model. A 12.5-m-long one-third scale AASHTO-type control beam was experimentally investigated for its flexural behavior when reinforced and prestressed with CFRP. Subsequently, a one-third scale bridge model made of five such beams was constructed, instrumented, and tested under both service and ultimate load conditions. As anticipated, the control beam and the bridge model failures were initiated by rupturing of the prestressing CFRP tendons at the bottom layer. The observed flexural response of the bridge model was in close agreement with that of the control beam. As expected, the failure mode was progressive, with extensive cracking of the bridge model, which gives significant warning prior to the ultimate collapse, overcoming issues related to the otherwise brittle behavior of the CFRP-reinforced structures. It is therefore highly recommended to provide the CFRP tendons in different layers along the depth of the beams to effectively address the issues related to brittle failure exhibited by CFRP reinforcements.