I-80 overpass adding turn lanes, sidewalk, in West Branch

The I-80 overpass in West Branch that sustained damage in 2007 will come down later this summer as part of a interchange project that includes a wider overpass.

Construction began this spring on the new overpass under a $2.9 million contract with Iowa Bridge & Culvert of Washington.

The old overpass had been under the microscope since a dump truck struck the structure in November 2007, causing a 35-foot crack in a beam. The Iowa Department of Transportation initially planned to replace the damaged beam as part of a project to replace the worn deck of the overpass.

Plans to replace the bridge deck changed in 2008, when DOT officials found out the project would cost $486,000. They decided a better decision would be to expedite replacement of the two-lane overpass with a longer structure that would allow for the widening of I-80 to six lanes.

The new structure also will be wider, DOT Resident Construction Engineer Carey Lewis said, with a third lane that will be used for turning movements onto the interstate.

A 10-foot-wide sidewalk incorporated into the bridge will allow more pedestrian access to the south side of West Branch, Mayor Don Kessler said.

Kessler said the old bridge has not been a problem for the city, but the DOT decided that it was time for it to be replaced.

Lewis said the project also includes new lighting and signals. It has already widened the turning radius of the off- and on-ramps to make turning movements easier for vehicles.

The turning radius issue was raised at the request of Acciona Windpower, which manufactures huge wind turbines in West Branch.

Lewis said the bulk of the interchange work will be completed during the 2010 construction season. Some of the work on the new overpass approaches will be completed in early 2011, Lewis said, because of the need to wait for settling of soil excavated for the overpass.

The current overpass has remained open to two-lane traffic most of the time during construction of the new overpass, Kessler said, although at times a flagger has been used to direct traffic.