STUDIES ON THE USE OF HIGH-PERFORMANCE CONCRETE AND FRP REINFORCEMENT FOR THE I-225/PARKER ROAD BRIDGE

The Colorado Department of Transportation (CDOT) recently completed a bridge structure at the I-225/Parker Road Interchange southeast of Denver using innovative construction materials. Part of the bridge deck was constructed of a crack resistant high-performance concrete (HPC) mix and fiber reinforced polymeric reinforcement (FRP) under the sponsorship of the Innovative Bridge Research and Construction (IBRC) program of the Federal Highway Administration (FHWA). To support and validate the design of the bridge deck using innovative materials, a series of studies were conducted at the University of Colorado at Boulder. The studies include the development of HPC mixes, evaluation of the mechanical properties of FRP reinforcing bars under static and cyclic fatigue loads with environmental preconditioning, evaluation of the load carrying capacities of full-scale precast panels prestressed with FRP tendons, and finally, evaluation of the long-term fatigue endurance of a model bridge deck, part of which had a design similar to the actual bridge deck with FRP reinforcement at I-225/Parker Road. Furthermore, the applicability of the AASHTO empirical method to the topping slab of precast panel decks was also investigated. A rational limit-state design method that can result in a significant reduction of deck reinforcement as compared to the conventional design method of AASHTO has been developed as an alternative to the empirical method. This report summarizes the test procedures and outcomes of these studies. Detailed information on these studies can be found in the original reports. The HPC and FRP reinforcement studied in this project were already used by CDOT in the I-225/Parker Road project. This project provided an excellent opportunity for both CDOT and the contractors to become familiar with the handling, performance, and overall use of HPC and FRP products in bridge construction. Results of the reported studies validate the applicability of FRP products for bridge construction and provide useful guidance on the use of such materials for future projects. The HPC developed in this project is now widely used by CDOT for bridge deck construction.