Innovative Jakway Bridge nominated for quality award

AURORA - The new Jakway Park Bridge in Buchanan County can certainly be called “Innovative”. It could be this innovative style that got the bridge nominated as an Iowa Quality Initiative Structures Award contestant.

It is the first highway bridge 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 second highway bridge project in Iowa and North America to be built with UHPC girders -- providing another, significant step towards “The Bridge of the Future.”

Buchanan County was granted funding for this project through the TEA-21 Innovative Bridge Construction Program (IBRC), managed by the Federal Highway Administration (FHWA) to construct a highway bridge using an optimized pi-girder section with (UHPC).

The Office of Bridges and Structures at the Iowa Department of Transportation and the Bridge Engineering Center at Iowa State University designed the bridge; a combination of cast-in-place, simple span slabs with a center span consisting of a series of precast UHPC pi-shaped girders.

The bridge is 24 ‘ 3 “ wide by 112’ 4” long. The UHPC center span is 51’ 2”

THE MATERIAL

Developed in France during the 1990s, UHPC has seen limited use in North American bridge projects. Consisting of fine sand, cement, and silica fume in a dense, low water-cement ratio mix, this highly moldable material offers a combination of superior properties including compressive strengths up to 30,000 psi and flexural strengths up to 6,000 psi, ductility, durability and a vast range of aesthetic design possibilities.

UHPC is denser than conventional concrete which attributes to its remarkable imperviousness and durability. In addition, UHPC is extremely low in permeability and performs better in terms of abrasion and chemical resistance, freeze-thaw, carbonation and chloride ion penetration (less than 0.5 mm). To improve ductility, steel or polyvinyl alcohol (PVA) fibers are added, replacing the need for passive mild reinforcing steel.