BOISE, Idaho — Bridge construction is usually a difficult and time-consuming process.
But over the weekend, construction crews managed to slide the first of two new bridges at the Blacks Creek Interchange on Interstate 84 into place.
The slide-in-place maneuver was designed to minimize impacts to the heavily traveled interstate. Crews construct most of the new bridge right next to the existing structure. Then, the old bridge is demolished and the replacement structure is slid into place.
"The driving force behind choosing a lateral bridge slide method was our focus on the people we serve and their ability to get where they need to go." said Patrick Kelly, the ITD project manager overseeing the work. "We were able to keep lanes open during the entire bridge construction process. Once it was ready, we closed the eastbound lanes, demolished the old structure, pushed the new bridge into place, and are wrapping up construction on the adjacent roadway. In the end, we will have closed interstate lanes of traffic for weeks rather than months."
The entire process takes two to three weeks. Normal bridge replacements can take several months. Crews still have some finishing touches to complete on the new bridge.
"Seeing how smoothly the bridge slid into place was very satisfying." said Kelly. "It has been months of planning, preparation, and a lot of hard work to get to this point. The crews from Knife River have done a wonderful job and should be very proud of the work they've done."
This method has been used before in 2014 when the Lardo Bridge on Idaho 55 in McCall was replaced.
The second bridge for the westbound lanes has been constructed next to the old structure. Crews are currently finishing up the eastbound side of the interchange. They will be ready to slide the westbound bridge into place in early August using the same method.
