U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
In the U.S. today, there are over 160,000 bridges that are structurally deficient or obsolete, and more than 3,000 new bridges are added each year.(1) Federal, State and municipal bridge engineers are seeking new ways to build better bridges, reduce travel times, and improve repair techniques, thereby reducing maintenance. Additionally, owners are challenged with replacing critical bridge components, particularly bridge decks, during limited or overnight road closure periods.
In response to these challenges, researchers at the Federal Highway Administration (FHWA) Turner-Fairbank Highway Research Center began investigating potential solutions in 2000. Prototype designs of full depth ultra high performance concrete (UHPC) waffle deck panel systems have been in development over the past 6 years in both Europe and the U.S.
UHPC provides superior durability against chlorides, freeze-thaw effects, salt scaling, abrasion, accidental impact, fatigue, and overload, thereby extending the useful life of the bridge deck. Combining these positive attributes of UHPC and the efficiency of the waffle panel design provides an extremely durable option that enables faster construction and longer girder spans through the efficient use of materials and reduced weight. In addition to these benefits, the UHPC waffle panel bridge deck system is applicable to both new construction and the rehabilitation of existing deteriorated bridge decks. Using this solution for bridge rehabilitation not only restores the deck but also provides opportunities for upgrading load capacity through the improved strength and reduced deck dead load.
Numerous State departments of transportation (DOT) and the FHWA have expressed significant interest in using full depth UHPC waffle deck panels. By demonstrating this system is a viable solution to the problems encountered by design engineers, it is hoped that it will revolutionize the way bridges are designed in North America.
The research conducted under this project was divided into two phases. Phase 1 included the design and testing of a mock-up bridge section for verifying design assumptions, as well as evaluating the feasibility of manufacturing and installing the deck elements. Phase 2 consisted of the construction of a full scale two-lane bridge on a secondary road in Wapello County, Iowa, using prestressed concrete girders and 14 UHPC deck panels. This report describes the results of both Phase 1 and Phase 2.