Work Resumes on State’s Longest Bridge – Tanana River Crossing in Salcha

Feb 18, 2013

Work is again under way in earnest on the state’s longest bridge, after a few weeks of down time over the holidays. The workers are hustling to complete several projects at the construction site in Salcha, and they hope to begin a new one – laying massive girders – before the ice begins to move on the Tanana River.

Workers building the Alaska Railroad's Tanana River Crossing bridge in Salcha must remove the causeway and other temporary structures in the riverbed before the ice begins to move this spring. The large vertical structure shown in this fall 2012 photo is the first of 18 piers on which the bridge will be built.
Credit Alaska Railroad

Salcha residents are once again hearing the big piledriver hammering steel piers into the Tanana River bed, signaling the resumption of work on the Alaska Railroad’s 3,000-foot bridge that when completed next year will help military vehicles and personnel get over to the sprawling training ranges on the other side.
Project Director Mark Peterburs says contractors are working against a deadline imposed by Mother Nature.
“Right now, it’s a race to get all the work that we’ve started finished, before the river breaks up,” Peterburs said.   
Peterburs says workers have a lot to do over the next couple of months, including removal of the temporary bridge deck, or causeway, that was erected to help workers and equipment get from pier to pier to build the permanent structure.
“Before breakup,” he said, “we will take all that causeway out, all the riprap (large rocks used for fill), all of the temporary bridge, temporary trestle -- that’ll all be pulled out. And any leftover work from the piers – the coffer dam, the sheet pilings and all that – will all be removed.
“We don’t want to leave anything to cause any kind of ice buildup in the river, other than what’s going to be there permanently, which is the piers of the bridge.”

Eighty girders like this are being delivered to the bridge construction site through the next several months. The girders measure 165 feet long, 11 feet high and weigh 165,000 pounds.
Credit Alaska Railroad

Peterburs says the temporary structures could be damaged or destroyed by the powerful movement of river ice. And, he says they must be removed to eliminate as many objects as possible that could snag ice and cause surface water to back up and flow where they don’t want it to go – especially into residential areas along the Salcha side of the Tanana.
“We’ll see how the levee performs,” he said. “This’ll be the first breakup with a substantially completed levee.”  
Alaska Railroad officials have said the levee should help reduce the flooding that occurs just about every Breakup season in residential areas just downriver from the bridge.
A progress report on the project issued by the railroad last month states that the contractor, Kiewit Infrastructure West, won’t be able to as hoped complete work before Breakup on 14 of the 18 piers that will support the frame on which railroad tracks and a roadway will be built.
But Peterburs says overall the project is going well. He says among other things, they hope to get ahead of schedule on setting in place a few of the massive, 165-foot steel girders between piers before the ice moves.
“We were able to get the girders from the fabricators sooner than had we expected,” he said. “So, this’ll give us a chance to get ahead of that. That really wasn’t scheduled ’til next fall.”  
Railroad officials advise motorists that one of the slow-moving, extra-long convoy of three tractor trailers and support vehicles is expected to arrive later this week. Another is scheduled for next week.