(The following story by Dylan Rivera appeared on The Oregonian website on August 10.)
PORTLAND, Ore. — The busy Willamette Boulevard bridge in North Portland is like few others in Oregon: Nearly 100 years old, it features original curved ironwork for rails and a dark Erector Set-like maze of steel holding it up.
That’s the good news.
The ironwork is severely rusted, a hole in the guardrail is patched with wooden planks, and portions of the complex understructure show weaknesses serious enough to result in “local failures,” engineering reports state.
About 10,000 cars cross the bridge each day, thumping cracks in the pavement and at times sending vibrations through passing pedestrians. This week state inspectors descended upon the Willamette Boulevard bridge as part of an inspection deployment after the collapse of a similar deck truss bridge in Minneapolis.
This one’s in worse shape, however, reports show. And it may be because its inspections are carried out by the state of Oregon, the road leading to it belongs to the city of Portland, but the bridge’s repairs are the burden of its owner, Burlington Northern Santa Fe Railway in Fort Worth, Texas.
A century-old agreement allowed the railroad to carve out of the North Portland bluff a ravine to allow passage of trains — and then build a bridge over it. A key structural support of the bridge has been rated in serious condition for about a decade, and the city has pushed since at least 2003 for better maintenance of the rusting hulk.
The Willamette Boulevard bridge is similar to the Minneapolis bridge that recently collapsed, but engineers have rated it in worse condition on the main measures of bridge health.
Standing by inspections
On Thursday, after several days of questions from The Oregonian, Burlington Northern ordered an in-house team to inspect the bridge, spokesman Gus Melonas said. But the company stands by its past inspections, which occur every six months, he said.
“Through our in-depth inspections that have occurred, there is nothing that inhibits load carrying capacity on this structure,” Melonas said. “We will review these reports of concern and follow up as necessary.”
The piers that keep the roadway about 80 feet above the ravine floor are held by foundations rated in serious condition. That situation is of most concern to engineers.
State officials said they did not have details available on what that means, but federal guidelines say the rating could indicate “fatigue cracks in steel or shear cracks in concrete may be present.”
A similar city- or state-owned bridge likely would have been overhauled long ago, city and state officials said. But Burlington Northern’s engineers have a different take on its condition.
“They seem to push materials further,” David O’Longaigh, supervising engineer in the Portland Office of Transportation’s bridge department said. “They think they can get more out of structures than we think we can get out of it.”
Not the worst
But the Willamette Boulevard bridge is not the worst span in the state. Some rural bridges are in worse condition, according to the Federal Highway Administration’s database of bridge ratings.
Still, among the steel deck truss bridges in Oregon, Willamette Boulevard and the Sellwood Bridge stand out as having the worst ratings from professional engineers and by far the highest traffic volumes of the most decayed spans.
Engineers are planning a Sellwood Bridge replacement, even though funding remains elusive. But a Willamette Boulevard replacement or overhaul has been mired in haggling over funding of inspections and arcane engineering differences between the city, state and railroad.
The Oregon Department of Transportation will include the Willamette Boulevard span in a load rating study to begin next year, said Bert Hartman, bridge program manager. That may reveal the structure’s real capacities and result in limits on heavy truck use or structural overhauls.
The maintenance issue was anticipated a century ago. In 1906, then-Portland Mayor Harry Lane vetoed a proposal to let the Portland and Seattle Railway Co. carve the ravine through North Portland, connecting a Willamette River rail bridge to one over the Columbia River. The City Council overrode him, allowing the railroad to sever 18 city streets, but requiring it to build four bridges to maintain traffic and pedestrian access.
The railroad agreed to maintain four spans — including the Willamette Boulevard bridge — at its own expense, according to the city ordinance.
But it doesn’t take an engineer to see that the bridge is in worse shape than most.
Its iron lattice guardrail is covered in rust and peeling paint. A chain link fence extends the guardrail about another 4 feet high. A hole in the guardrail is patched with thin slats of wood, like a household fence.
“Obviously it doesn’t meet current standards,” O’Longaigh said. “The railroad has carried out their repairs. But they are definitely below where the city of Portland would repair the rail to.”
About 10 years ago, engineers rated the bridge’s substructure a three on a scale ranging from zero, “failed condition, out of service,” to nine, “excellent condition.”
The substructure remains rated a three, according to an inspection from September 2006. But its deck, which includes the road surface, and the superstructure, which includes the trusses that support the deck, have both deteriorated. Ten years ago, they were both rated a five, or “fair condition.”
Today, they’re both rated a four, or “poor condition,” which could indicate advanced section loss, according to federal guidelines.
In early 2003, city inspectors asked state officials for help urging the railroad to re-inspect the span. By July 2004, a railroad inspection gave the substructure and superstructure an eight rating and a seven for the deck.
But the railroad used railroad bridge inspectors, not inspectors trained to judge highway and other spans that go in a federal inventory, said Bruce Johnson, state bridge engineer for Oregon.
“They were not certified as highway bridge inspectors in Oregon, so they didn’t have the training to judge the bridge” in line with federal guidelines, he said.
O’Longaigh noted that the September ratings were lower than previous ones. He called Hartman and asked that the Willamette Boulevard, as well as a similar span on North Fessenden Street, be included in the next round of “load ratings” the state orders.
That study will most likely start next year, Hartman said. The state may also add a similar North Lombard Street span that is in better condition.
Meanwhile, Willamette Boulevard will continue to have inspections every year, rather than every two years as most bridges do, Hartman said.
“We want to keep an eye on this bridge,” he said.