Full metal jacket: Bridge columns wrapped in steel underneath a bridge along Interstate 5, south of Seattle. Credit: Bill Lucia
Funds for strengthening western Washington's bridges against earthquake damage could drop significantly in the next budget cycle, according to the state's transportation department.
For over two decades, the Washington State Department of Transportation has reinforced bridges with additional steel and concrete in an attempt to make them less susceptible to catastrophic collapses and other, less severe, structural failures during earthquakes.
WSDOT has retrofitted 286 bridges as of late August; an additional 478 spans are still in need of seismic upgrades. But two major funding sources that have helped pay for this work are about to run dry. As a result, the amount of money WSDOT expects to have available for these projects in the next budget cycle is currently slated to decline by about 80 percent.
In the 2011-2013 cycle, the agency spent roughly $18.7 million on retrofits. Between 2013-2015, the retrofit budget was around $22 million. The amount WSDOT plans to include for seismic retrofits in its 2015-2017 budget request, a figure based on the agency's anticipated funding constraints, is about $4 million. A WSDOT spokesperson said that because the cost of retrofit projects varies widely, it is not possible to project how many bridges could be upgraded with this lower level of funding.
According to state bridge and structures engineer, Tom Baker, the immediate public safety hazards posed by un-retrofitted bridges is relatively low. "If our bridges are open, they're safe," he said during an interview last week. "I'm not concerned driving around western Washington, worrying about the structures under me collapsing in an earthquake."
But the risks to motorists caught on a bridge span during a quake are not the only potential problem.
"It's important that we have the bridges on key routes standing and usable after an earthquake," said Mark Stewart, a spokesperson for the Washington Military Department's Emergency Management Division. "It's not only for the emergency response, but to aid the recovery afterwards."
A badly damaged bridge along a major corridor like Interstate 5 could not only handicap first responders. It might also snarl traffic and freight in the days and weeks after a quake while repairs take place, exacting an economic toll on the surrounding area.
The financial uncertainty hanging over the seismic retrofit program is not unique. "It's one of many examples of why we need to pass a transportation revenue package," said state Sen. Steve Hobbs, D-Lake Stevens, vice co-chair of the Senate Transportation Committee.
The so-called "Nickel Package," which the Legislature adopted in 2003, and the 2005 Transportation Partnerships Act were key sources of cash fueling seismic retrofit projects in recent years. Now the work those funding measures helped pay for is coming to a close. "As that finishes," said WSDOT's Baker, "there aren't continuing funds to go and do more retrofits."
The Transportation Partnerships Act alone provided $87 million to upgrade 172 bridges in the central Puget Sound region. The account funded over 270 transportation projects during a 16-year period using gas tax and vehicle weight fee increases. The Nickel Package paid for 158 WSDOT projects over 10 years using the same revenue sources along with an increase in the sales tax on motor vehicles.
Neither Sen. Curtis King, R-Yakima, who co-chairs the state Senate's Transportation Committee, nor Rep. Judy Clibborn, D-Mercer Island, the House Transportation Committee chair, responded to requests for comment on Wednesday about the seismic retrofit program.
While he emphasized that he was not an expert on the specifics of the transportation budget, Ross Hunter, D-Medina, who chairs the House Appropriations committee, echoed Hobbs's call for a new comprehensive revenue package to cover transportation costs. "We underfund maintenance on our roadways by a tremendous amount," he said. "We're going to have to find some new revenue in order to fund a new maintenance plan."
Throughout last spring's legislative session, the state Senate's Majority Coalition Caucus was at loggerheads with House and Senate Democrats over the details of a multibillion-dollar transportation package. A compromise floated by Hobbs did not get enough traction to break the impasse. Similar to other proposals, his plan included a phased-in 11.75-cents per gallon gas tax increase.
In Hobbs's view, the dearth of retrofit funds is a sign of things to come. "This is going to continue as the TPA and The Nickel go away," he said.
In recent months, multiple earthquakes measuring about 6.0 in magnitude struck north and south of Seattle — two in southeast Alaska in July, and another near Napa, California in late August. Those quakes did not cause any major harm to bridges.
"In the most recent earthquakes we've had I can't think of any damage we've observed," said Richard Pratt, chief bridge engineer at the Alaska Department of Transportation.
Alaska also began a seismic retrofit program for bridges back in the 1990s. Pratt said that as of 2009, about 100 bridges had been strengthened. Whether that program has made a difference during any of the state's recent quakes is hard to say. "We're so sparsely populated that the majority of these earthquakes are in areas where no one lives, so there's nothing to be damaged," Pratt said.
Brick-sized chunks of concrete fell off at least two bridges during the recent Napa quake and the pavement was damaged on the approach road to another, according to Vince Jacala, a spokesperson for California's department of transportation. Despite this minor damage he said, "The bridges are safe and were safe for motorists to cross over."
Those overpasses, according to Jacala, were about 40-50 years old, the same age as many of the ones on Washington's retrofit list.
During the 2001 Nisqually earthquake approximately 40 state bridges suffered some damage, along with 22 of Seattle's city bridges, according to a report written that year by the Nisqually Earthquake Clearinghouse Group. None of the bridges collapsed.
The 6.8 magnitude Nisqually quake also compromised the Alaskan Way Viaduct, resulting in millions of dollars in repair work and eventually prompting the Highway 99 tunnel project, which is now stalled while Bertha, the boring machine which is supposed to dig the path for the underground roadway, is repaired.
The Clearinghouse Group report noted that retrofit measures taken in the decade prior to the quake had "undoubtedly reduced the amount of damage and loss of life that would otherwise have occurred."
Marc O. Eberhard is a professor of structural engineering and mechanics at the University of Washington and one of the authors of the report. "There's no doubt that standard retrofit measures improve seismic performance by a lot," he said, adding that, as earthquakes go, the Nisqually was "quite gentle," and "wasn't a very severe test by any means" of the region's infrastructure.
If and when a stronger test occurs remains uncertain. In the meantime, 120 retrofits are partially completed on state bridges, in addition to the 286 that are already finished. Another 29 are underway.
On Tuesday, a crew worked beneath a bridge that Interstate 5 crosses over in Kent. Workers were setting up wooden forms under the north side of the structure so they could pour additional concrete, which will reinforce a cross beam that supports the bridge deck.
Workers reinforcing an Interstate 5 bridge in Kent. Photo: Bill Lucia
Some of the cylindrical concrete columns that support the bridge deck had also been wrapped in steel. "The whole idea is that in a seismic event, the column can't go anywhere," said WSDOT's chief inspector, Sam Al-Mallah, as he stood underneath the bridge explaining the purpose of the steel "jackets" surrounding the columns.
The wider beams and jackets are common retrofit techniques in Washington and other quake-prone regions.
WSDOT's Baker said maintaining the funding for these types of projects is vitally important. "Whether you're riding a bus, or a taxi, or driving your own car, or car-pooling, you want to keep that mobility to move around," he said. "That means taking care of the infrastructure."
And that means finding enough money to do so. "For those of us who live in the world of asset management funding is always a constraint," Baker allowed. "We live in a society of scarce resources."