Design, Construction, and Monitoring of US Longest Highway Bridge Span Prestressed with CFRP Strands

Prestressed with carbon fiber-reinforced polymer (CFRP) strands, a 42.2 m (138.3 ft) long single-span highway bridge superstructure was recently constructed to carry Interstate I-75 Highway over Sexton/Kilfoil Drain in Allen Park, MI. Experimental and analytical investigations were executed to overcome design challenges such as establishing the level of prestressing force, applicable strength reduction factors, and proper mode of failure to ensure an adequate performance under AASHTO LRFD service and strength limit states. After bridge construction, onboard sensors were used to verify its performance under traffic load and different environmental conditions. This manuscript provides details on an experimental investigation that was conducted to evaluate the constructability and possible failure modes in CFRP prestressed beams. In addition, the manuscript highlights key findings in the process of bridge design, construction, and field monitoring. To overcome the absence of yield phenomenon in CFRP and to establish visual warning before failure, beams prestressed with CFRP strands can be designed to achieve large deflection and extensive cracking patterns prior to failure. In addition, CFRP prestressed beam bridges, such as I-75 bridge, perform as analytically expected under service loads with a considerable load carrying capacity. Furthermore, and in the light of the multilevel strength reduction factors implemented in design, sufficient reserve capacity is embedded in the design to ensure adequate bridge resistance through its lifespan.