Visitors to Des Moines for the various state tournaments this month are seeing not only a new arena for play, but lots of changes in interstate system through the capital city. The Department of Transportation says this is the largest construction project in its history.

Bill Lusher is overseeing the work for the D-O-T and says they’ve used some innovative techniques in the construction — including one used for the retaining walls that line the roadway. He says the soil-nail retaining technique allows them to build the retaining wall from the top down, which he says is less intrusive and allows them to build without disruptive utilities and the soil as much as a normal wall.

Lusher says the specifications for the freeway required them to use the new retaining wall techniques. He says they were asked to be a “minimum intrusive” construction environment, meaning they would build in the existing right of way without taking out many new homes. Lusher says that required them to build more retaining walls.

Lusher says there are lots of other unique designs in the new system. He says one of the things that’s quite evident is the new arch pedestrian bridges that use and arch to hold up the bridges and don’t require a center pier to hold them up. Lusher says the blue arch is “a nice visual aspect to the freeway corridor.” Lusher says the new freeway was a chance to break in some new designers.

Lusher says they gave a lot of the young engineers and technicians in the design officer a chance to work on the project and he says it allowed them to immerse the young staffers in the design process. Lusher says the D-O-T will be a much better organization as a result of the experience the young designers have gained. Lusher says the project is scheduled to be completed by 2007.