Innovative design chosen for new Buchanan County bridge

QUASQUETON — Another innovative Buchanan County bridge project got underway Aug. 11 with the demolition of a 62-year-old bridge spanning Nash Creek on County Road W-35.

Seeking to promote their products, two firms will donate the main bridge structure — seven 70-foot glue-laminated wood beams — and the hardware for the project, said Buchanan County Engineer Brian Keierleber.

'We should be getting a $300,000 bridge for about $85,000' — the cost of labor and concrete, he said.

Keierleber said the beams will be manufactured by Gruen-Wald Engineered Laminates of Tea, S.D., while the hardware will be provided by Sioux City Foundry.

The new 40-foot-wide bridge replaces a 21-foot-wide structure where two dump trucks met last year, each leaving behind their driver's side rearview mirrors.

Keierleber arranged a similar cost-saving project a year ago. A bridge south of Jesup on County Road V-65 was replaced as part of a demonstration project showcasing the advantages of a new design software developed to reduce the cost of bridge construction.

With participation from several steel bridge vendors, the demonstration project enabled Buchanan County to get a $240,000 bridge for less than $100,000, Keierleber said.

This week the county also will complete its 23rd bridge replacement project, in which used steel railcars are adapted to support the bridge decks at a cost savings of at least $100,000 per bridge, he said.

Keierleber said his position as chairman of the Structures Committee of the National Association of County Engineers enables him to make industry contacts for research projects aimed at 'building better bridges more economically.'

In Keierleber's 21 years as county engineer, Buchanan County has replaced almost 100 of its 259 bridges, he said.

The bridge being replaced carries about 900 vehicles per day, according to Iowa Department of Transportation Statistics. Its sufficiency rating of 23 is well below average for the county.

Assistant county engineer Alex Davis, who is managing the W-35 project, said the new bridge is expected to open in mid-October.

Davis said the bridge deck will be affixed to the laminated beams with an adhesive that should strengthen the bridge while protecting the beams from weather exposure.

The project also includes a separate pedestrian lane that will be completed once the main bridge is back in service.