Serviceability of Beams Prestressed with Hybrid Steel/Carbon Fiber-Reinforced Polymer) Tendons

Service life of existing post-tensioned concrete members is significantly impacted by the corrosion of its unbonded steel tendons. This deterioration, commonly initiated by the penetration of chloride ions front deicing salts or grouts, is exacerbated by increases in live and superimposed dead loads. There is a need to develop more durable and improved design alternatives with enhanced serviceability, ductility, and strength performances. This study fbcuses on the serviceability performance of hybrid beams prestressed using a combination of bonded and unbonded steel and carbon fiber-reinforeed polymer (CFRP) tendons. Eighteen beams were tested to failure under thini-point loading with emphasis on the tendon materials' (that is, CFRP and steel) performance. Results show that hybrid beams, using CFRP as the unbonded element, are very robust prestressing systems that may achieve extended service life due to their corrosion resistance, while maintaining comparable service performance when compared to hybrid steel beams.