Strength Reduction Factors for Fiber-Reinforced Polymer-Prestressed Concrete Bridges in Flexure

Abstract

This paper addresses the calibration methodology of strength reduction factors for fiber-reinforced polymer (FRP) tendons used in prestressed concrete application. A total of 50 benchmark bridges are designed using aramid FRP (AFRP) and carbon FRP (CFRP) composites in accordance with the geometric and material properties of constructed bridges. Stochastic simulations are conducted to attain several subdesign factors necessary for calibrating the strength reduction factors of FRP-prestressed concrete bridge girders, based on the reliability requirements of the American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) Specifications. The proposed methodology is validated with published reliability responses, and further employed to determine resistance parameters and to identify a resistance distribution at the system level. The strength reduction factors of AFRP- and CFRP-prestressed girders are not significantly different from each other and, consequently, integrated reduction factors of 0.75 and 0.80 for tension-controlled and compression-controlled sections are suggested to update the reduction factors of ACI 440.4R-04.