Prefab Bridges touted as trucking aid

LAS VEGAS. A highway contractor stated that municipalities will increasingly look to “prefabricated” bridges as a means to cut construction times, as well as the resulting traffic congestion, here at the 86th annual meeting of the Associated General Contractors of America.

“The big reason we’re now using these methods is to reduce the cost to the traveling public of time spent in traffic due to construction and extra fuel spent on detours and congestion,” Richard Lawrence, president of Colorado-based highway contractor Lawrence Construction Co., told Fleet Owner.

Lawrence pointed to a bridge project his company performed for the state of Colorado to replace a busy two-lane highway bridge that carried over 10,000 vehicles daily. Instead of a three- to four-month project that would have shut off one lane at a time over the bridge as it was replaced, his firm closed the road and replaced the entire structure in two days. That was because the entire structure was almost completely pre-built before being installed.

“We did it with no accidents as well, because the road was closed to traffic,” he said. “People went home on a Friday and when they went back to work the following Monday, the new bridge was in place. There was no real interruption in traffic flow.”

Lawrence Construction also replaced two bridge spans in a 14-day period instead of the year and half projected for the standard build-in-place method. “Think of the time and disruption we saved highway users – commercial and commuter alike – by not having them use an alternate route for nearly 18 months,” Lawrence said.

Though widely used in Europe, the pre-fabricated Fast Track bridge construction method is only slowly catching on in the U.S., Lawrence noted.

It can be more costly, for starters, in terms of pure construction dollars spent up front; almost double the build-in-place model. However, the life span of a pre-fabricated bridge can be longer since the contractor has better quality control over the structure compared to when it’s built in place, Lawrence said. Also, moving to a pre-fabricated Fast Track style of construction can conflict with years of state engineering studies that recommend build-in-place bridge methods as the most cost-efficient option.

“Basically, it’s going to take time and research dollars to prove the pre-fabricated Fast Track method is a better option,” Lawrence said. “Once we get research data to support it, then I think we’ll see a switch really fast.”