UPDATE 5:30 p.m.: The trucker whose load destroyed an I-5 Skagit River bridge span Thursday told federal investigators he heard no warning from a pilot-car driver about the pending disaster.
He also told investigators he was driving to the right – where the minimum clearance was only 14 feet, 6 inches – hauling a wide load, while another truck was in the left lane.
“He said he saw this truck approaching and passing him as he was traversing the bridge,” NTSB board Chairwoman Deborah Hersman in a news conference Saturday. Clearance is higher in the left lane, because of the elliptical shape of the beams.
Hersman said the NTSB will conduct more interviews, look at video evidence and examine tire marks before reaching any conclusions.
The pilot car company and the 41-year-old truck driver, William Scott of Alberta’s Edmonton area, both had experience traveling this part of I-5, and met at the Canadian border before heading southbound Thursday, said Hersman.
The truck was carrying drilling equipment, under an overheight-load permit of 15 feet 9 inches, when the load appeared to have damaged or nicked about 10 overhead cross-members of the steel truss bridge. One span fell into the water, and a second span was damaged.
The worst-damaged of the crossbeams is underwater, Hersman said, who had a close-up look by boat.
“When you’re down that close, the trauma of the bridge collapse is evident,” she said, describing the beams as wide as a human, the deflated airbags in one vehicle that fell, the swirling currents washing through an open pickup door. The concrete deck “slid off its girders like frosting off a cake,” she said.
Hersman also said Saturday that the state Department of Transportation may begin to remove bridge wreckage and two fallen vehicles from the water, as soon as WSDOT can get equipment in place. The NTSB can examine parts “in parallel” with a state removal effort, she said.
On Friday, WSDOT signed a contract with Atkinson Construction to remove the wreckage, and build a new span suitable for permanent use by all traffic including interstate trucks, said agency spokesman Bart Treece.
The investigation’s early facts point to a couple potential gaps in state regulations:
- There is no state requirement to post bridge clearances unless they are 14 feet, 4 inches or less, and this bridge wasn’t posted, said Hersman.
- There is no requirement to have a pilot car in the rear, which might have deterred passing what was both a high and a wide load.
On Friday, state Transportation Secretary Lynn Peterson said the clearance is 15 feet 6 inches at the fog line. Government records say the maximum clearance is 17 feet 6 inches.
The NTSB intends to interview the pilot-car driver, said Hersman. Also, the truck will be moved to a secure location and measured on level ground, and another similar load north of Burlington will be measured, she said. The team includes an engineer and a metallurgist, she said.
The NTSB makes safety recommendations but cannot require changes in law, nor does it have power over approving roadway designs, or in this case, any replacements or fixes to the Skagit bridge.
EARLIER POST: Washington state is moving rapidly to reopen the collapsed Skagit River I-5 bridge by hiring Atkinson Construction on an emergency $15 million contract, outside the normal bidding and review processes.
A pair of Atkinson superintendents Saturday examined the north end of the bridge, where one of four spans of the steel-truss bridge fell Thursday evening.
The fix, which is being designed by state engineers, is meant to be permanent and to carry fully loaded trucks, which are a mainstay of the West Coast’s economy, said Bart Treece, spokesman for the Washington State Department of Transportation.
He said it was unclear at this point whether a permanent span would be erected as a single job or if a temporary road deck — even a military style “Bailey bridge” — would operate in the interim while a permanent structure was assembled around it.
The wreckage shows another issue that hasn’t made news yet: the truck that brought down the north span also damaged the second span, where a vertical beam on the downstream side is bent after being pulled inward. The overheight truck hit “the transverse chord on the truss” at multiple cross beams, Keith Metcalf, the transportation department’s interim chief engineer, said Friday. From shore it’s easy to see paint scrapes and dents where overhead crossbeams were nicked or crumpled.
Atkinson will also be in charge of removing the wreckage after the National Transportation Safety Board (NTSB) finishes its onsite investigation, Treece said.
The $15 million figure is only a starting point to get the job underway, he said. “Everything is pretty early right now.”
One challenge will be fastening a new deck to the old 1955 concrete pier, which shows a bit of damage where the north span was uprooted and some concrete flaked off.
On Friday, Transportation Secretary Lynn Peterson said the condition of the piers would affect how the bridge can be fixed. NTSB Chairwoman Deborah Hersman said the piers, including parts underwater, will be checked closely to ensure the collapse didn’t weaken them.
Kevin McKeon, an Atkinson superintendent, said the problem is manageable by adding materials to “just make it wider at the top,” or otherwise fortify the piers. One thing in Atkinson’s favor is plenty of open space for its equipment.
The company has done many jobs for WashDOT, including the Nalley Valley highway in Tacoma, and many seismic retrofits, said Superintendent Mike Emerson.
About 71,000 vehicles daily use I-5 across the Skagit River. Detoured traffic was backed up one mile midday northbound at Mount Vernon, before the main exit. Local traffic in Burlington seemed heavy but shopping centers remained reachable with a few minutes delay.