BURLINGTON — State Department of Transportation officials, crews and contractors are working nearly around the clock at the site of the collapsed Skagit River Bridge to mitigate local traffic impacts and construct the temporary bridge span.
At one point Monday morning, subcontractors were removing the last piece of the collapsed bridge structure from the Skagit River, while crews on the north side were hard at work constructing a temporary span.
Meanwhile, state Trnasportation officials were finishing up a request for details on what the agency wants from contractors who hope to build a permanent solution.
A signal team was monitoring traffic along detour routes to see if any traffic light timing adjustments could improve traffic flow during the morning commute.
On a Monday morning tour of the bridge’s progress, Jay Drye, assistant regional administrator for the department, said crews are nearly finished removing the collapsed structure from the river.
Drye said work has been slow and precise to preserve the structure for investigation by the National Transportation Safety Board.
“This continues to be a very cautious, almost surgical recovery effort,” Drye said.
Peter Knudson, spokesman for the NTSB, said the agency is not holding up the construction of the temporary span or the recovery effort for the bridges.
“We are working alongside (DOT) as they are doing their salvage operation and documenting the pieces of the bridge that are of particular interest to us,” Knudson said.
Across a gaping 160-foot divide between remaining bridge sections, Drye pointed out ladder-like structures bracing damaged girders on the south side of the bridge.
He said the damaged but standing structures will be assessed to determine whether they can be straightened with heat and force, or need if sections must be replaced.
On the long, sloping northern approach to the bridge, crews from Guy F. Atkinson Construction worked in teams to assemble individual sections of the temporary span, which were then picked up by crane and built into the temporary span structure.
Drye said the temporary span will consist of two, 160-foot-long, 24-foot-wide (two lane) steel structures. Each will be built one at a time on the north side of the gap, fitted with an 80-foot-long “launch nose” and heavy counterweight in the back, and rolled across the water at different stages of construction, Drye said.
A rail system anchored to concrete pier caps currently under construction on the edge of the the standing portions of bridge will help guide the sections over, Drye said.
Once one section is over, it will have its launch nose removed and be jacked sideways to make room for the next section, which will be built and rolled over in the same fashion.
Drye said the department’s goal is to have the temporary bridge in place and operational between June 19 and 22, though the repairs to damaged girders and the results of an underwater piers inspection may push back the opening date.
Drye said he doesn’t expect to find any damage to underwater supports for the bridge, but inspection and testing is an obvious necessity before the bridge is back in use.
Speeds on the temporary span haven’t been decided, but Drye said he expects them to settle around 35 to 40 mph.
Overweight trucks also might not be allowed on the temporary span, he said.