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ACEC chapter picks Portneuf bridges best in 'structural systems'

The Portneuf River Bridges in District 5 emerged as the top engineering project in statewide competition sponsored by the Idaho chapter of the American Council of Engineering Companies.

It was chosen the best project in the “structural systems” category as part of the 2012 Engineering Excellence Awards competition.

The bridge project will be profiled at the annual ACEC of Idaho awards luncheon scheduled for April 9 in Boise. Selection as the statewide winner qualifies the project to be considered for a national ACEC award.

Replacement of two bridges over the Portneuf River is part of a 12--mile, $87.5 million U.S. 30 corridor improvement project between McCammon and Lava Hot Springs. The corridor improvements were the first to begin under the GARVEE (Grant Anticipation Revenue Vehicle) program approved by the Idaho Legislature in 2005.

The bridges project includes roadway improvements between Crystal Springs Road and the Old Oregon Trail Road, widening the highway from two to four lanes and replacing two undersized culverts with two new bridges. The Portneuf Bridges project accounts for approximately $27 million of the corridor improvements.

Designed by HDR, along with subcontractors Terracon and Parametrix, the bridge project included some design-build elements, including: stone columns, a soil nail wall and MSE walls.

The new Portneuf bridges will eliminate river restrictions created by the old 10-foot culverts they replaced. They also enhance wildlife access.

Expanding the U.S. 30 to four lanes allowed ITD to increase the speed limit from 55 mph to 65, which reduces congestion and improves traffic flow for motorists and the heavy amount of commercial vehicle traffic. They highway serves as a major access for commercial traffic connecting with I-80.

Completion of the project is anticipated later this summer after a final seal coat is added. It is projected to come in under budget.