The Jakway Park Bridge, UHPC Pi-Girder

Buchanan County, Iowa

Breaking new ground, this bridge was the first in North America to be built with a new generation of ultra-high-performance concrete (UHPC) pi-girders, the first North American highway bridge project to incorporate batching of UHPC in a ready-mix truck, and the third highway bridge project in North America to be built with UHPC girders. The UHPC girders themselves provide a superior combination of properties, including compressive strengths up to 30,000 psi, flexural strength up to 6000 psi, and greater durability because of the exceptionally low carbonation penetration, which results in a structure resistant to deicing salts and harsh environmental conditions. The testing of the first generation of UHPC validated the initial finite-element-method analysis and helped expose deficiencies in transverse stress resistance and a low ability to distribute live load between the new pi-girders. These two design challenges drove the development of the second-generation pi-girder, which is what is currently built. Ultimately, the new bridge not only breaks new ground in both the usage of UHPC and methods for its placement, but will also serve as an excellent example for engineers and precasters to learn about the design, testing, mixing, and casting methods of UHPC long into the future.

Precaster: Lafarge North America, Winnipeg, MB, Canada
Website: www.lafarge.com

Engineer of record: Iowa Dept. of Transportation, Ames, Iowa
Website: www.iowadot.gov

Deck area: 2883.4 ft²
Bridge length: 115 ft
Bridge longest span: 52 ft
Bridge width: 25 in.
Precast concrete components:
3 ultra-high-performance precast concrete pi-girders