The bridge collapse on Interstate 5 north of Seattle this week highlighted the nation’s aging infrastructure and the lack of significant improvements in the six years since 13 people died when a Minnesota span fell.
Investigators haven’t determined what caused the failure of a section of the bridge over the Skagit River in Mount Vernon, Washington, after a truck struck some of its steel girders. The collapse followed the commitment of $48.1 billion in U.S. economic-stimulus funds for transportation projects since 2009.
Governor Jay Inslee said state and federal officials are working to devise a temporary replacement, known as a Bailey bridge, to end traffic detours on the north-south highway that runs the length of the U.S. West Coast. State Transportation Secretary Lynn Peterson said yesterday the bridge should have withstood the blow from the passing truck.
The accident turned attention back to the age of the nation’s transportation system. The 607,380 bridges in the U.S. are 42 years old on average, and 1-in-9 are rated “structurally deficient,” according to the American Society of Civil Engineers, which advocates more spending on such structures.
“There are many places -- and probably the one that just collapsed is an example -- where bridges are being maintained but not replaced or improved to the extent they need to be because of the lack of available funds,” said Joshua Schank, president and chief executive officer of the Eno Center for Transportation, a research institute based in Washington, D.C.
The engineers group gave U.S. infrastructure a D+ rating in a report this year, with bridges scoring better at C+. That’s an improvement over 2009, when the last report card came out and gave them a C. The organization said fixing deficient spans would take $76 billion.
“There’s been more investment at the fed and state levels,” Casey Dinges, senior managing director of the Reston, Virginia-based engineers association, said in an interview. “There’s been more focus on bridges.”
The condition of urban spans hasn’t kept up with the national average and remains a concern, Dinges said. Vehicles make more than 200 million trips a day across bridges in the 102 largest metropolitan areas of the U.S., he said.
The 2007 collapse of the Interstate 35W bridge in downtown Minneapolis during rush hour sent cars plunging into the Mississippi River, killing 13 people. The tragedy spurred calls in Congress to raise federal fuel taxes, which didn’t happen.
Increasing spending on replacing or overhauling bridges wouldn’t be easy to achieve because 80 percent of most highway-project money comes from the fuel-tax fed U.S. Highway Trust Fund. The federal levy on gasoline has been 18.4 cents a gallon since 1993, and sales have slowed with declines in miles driven and improvements in vehicle efficiency.
“If we keep on the same trend line of investment, where we’re not increasing investment, we are going to have to worry in the future,” said Janet Kavinoky, executive director for transportation and infrastructure at the U.S. Chamber of Commerce, the biggest U.S. business lobbying group.
President Barack Obama’s $787 billion economic-stimulus package in 2009 poured $48.1 billion into highway and transit projects, yet accomplished little in terms of long-term improvement to bridges and other such infrastructure, Kavinoky and Schank said in interviews.
“A lot of places decided to do things like fill potholes and resurface streets,” Schank said. “It’s an emphasis on creating jobs instead of creating long-term economic growth. That emphasis means that transportation is not being thought of as a long-term driver of economic growth.”
A section of the 1,112-foot (339-meter) I-5 bridge collapsed two days ago at about 7 p.m. local time, dumping several vehicles into the river below and injuring three people. No one died, authorities said.
“Based on our inspections, the bridge is not structurally deficient,” Peterson said at a briefing in Mount Vernon, about 62 miles (100 kilometers) from Seattle. The bridge was subjected to a close inspection of impact damage by state transportation workers about six months ago, identifying tears and deformations, the Associated Press said yesterday.
Inslee, a Democrat, said a Bailey bridge is a temporary structure to replace the 160-foot section that fell. He suggested that federal funds may cover as much as 90 percent of the cost. He didn’t provide a timeline.
‘We are now engaged in a full-scale pursuit of trying to restore this artery of commerce as quickly as we can,” he said yesterday at a news briefing. The section of I-5 links Seattle to Vancouver.
The four-lane steel truss bridge that fell was built in 1955 and was considered “functionally obsolete,” according to the National Bridge Inventory Database. It carried an average of 70,925 vehicles a day. The span’s superstructure was rated as “fair,” meaning it was structurally sound with minor flaws such as cracks or pitting in its girders, according to the database report.
Out of more than 7,000 bridges in Washington, at least 540 were in the same condition or worse, according to the database.
About 14 percent of U.S. bridges were considered functionally obsolete in 2011, the most-recent year available, according to the U.S. Federal Highway Administration.
National Transportation Safety Board investigators are probing the causes of the I-5 collapse.
“Our mission is to understand not only what happened but why and how it happened,” Safety Board Chairman Deborah Hersman said yesterday at another briefing in Mount Vernon. “We want to make sure we do not have events where interstate bridges drop into the waterway below them. That is not what we expect.”
While the fallen span hadn’t drawn attention for its earlier condition, other bridges in the U.S. have been identified as potentially dangerous.
In New York, Governor Andrew Cuomo is replacing the 57-year-old, 3.1-mile Tappan Zee Bridge across the Hudson River. The span, about 20 miles north of Manhattan, was supposed to last for 50 years. It carries 138,000 vehicles a day between Westchester and Rockland counties, 40 percent more than its designers intended.
New Jersey will close its Pulaski Skyway, a major route to the Holland Tunnel and Manhattan, to New York-bound traffic for two years starting in 2014 for a $1 billion reconstruction project, raising concerns about commuting delays.
The 3.5-mile bridge, which has two 550-foot spans that cross both the Hackensack and Passaic rivers and was built about eight decades ago, carries 67,000 vehicles a day.
It has deteriorated since opening in 1932, and is “functionally obsolete” because certain features, including road width, no longer conform with modern standards, according to the New Jersey Transportation Department website. The Skyway has two 11-foot-wide lanes in both directions with no shoulders.
State lawmakers have said the bridge wasn’t properly maintained for decades.
The Skyway, which cost $20 million to build, is included in the National Register of Historic Places because of its historically significant design.