Thursday, June 20, 2013

D Street underpass project hits 'rocky' patch

The view Thursday from the top of the big hole at D Street and Yellowstone Avenue
Anyone who has driven on North Yellowstone Avenue since Wednesday has most likely noticed the big pile of rocks in the hole where the D Street Underpass used to be.

Crews blasted into 10 feet of basalt at 2 p.m. Wednesday to clear away space for the new bridge's footings, said Kelly Kofoed of Cannnon Builders, the city of Idaho Falls' contractor on the project.

The stones will be hauled away to a Landon Excavating pit. The tree immediately south of the stone tower is also slated to be removed next week. The city wanted to save the tree, but the excavation around the tower, which is actually a pump station dating back to around 1910, damaged too much of its root system, Kofoed said.

Building a bridge is a lot different than building a house or office building. "It's kind of like building a house around your wife while she's making dinner," Kofoed said. Cannon has also been the contractor on the John Adams Parkway bridge over the Idaho Canal, due to be finished in  July. "We had to go deep for the footings at the same time we had traffic going over it every day," he said. In the D Street project's case, train traffic had to be re-routed with a "shoefly," a four-month undertaking by itself. The new underpass is scheduled to open sometime in 2014.

The D Street excavation has yielded all sorts of interesting things: masonry foundations from buildings that made up the Oregon Short Line Railroad depot, which was torn down in 1964, and old tools that had been discarded by railroad workers decades ago.

Kofoed said he and his crew were the first people since the '60s to set foot inside the pump station. There was a hardwood floor that had rotted and a lot of sludgy water in the foundation, which goes down 30 feet. "I'm sure the old pumping equipment is in there," he said.