Cliches aside, the metropolitan area is about to turn itself inside out and jump through some unpleasant hoops, all to fix something that isn't broken.
At least, it's not broken yet.
But the experts say that sooner or later, a critical part of the lift mechanism on the 80-year-old Interstate Bridge will break.
In simple language, the problem is a crack in the axle of the pulley that lifts and lowers the part of the bridge that opens.
In engineer talk, the trunnion in the sheave assembly is fracturing.
The crack was detected a decade ago when Oregon was testing newly acquired sonic testing apparatus. More sophisticated tests recently confirmed the problem exists and showed it is getting worse with every bridge opening. The risk of failure will increase steadily until early in the next century, when the odds will skyrocket.
Experts aren't in total agreement about the consequences of an axle failure. One of the more extreme scenarios says the pulley would fall, allowing the counterweight to crash to -- and probably through -- the deck of the stationary span between the lift unit and the Vancouver, Wash., shore.
So, before the axle defies the odds and snaps, Christie Constructors of Richmond, Calif., has won the $2.87 million contract to replace the trunnion, sheave and 16 lift cables on the weakened corner of the bridge. While the crane is in place, the north tower's other trunnion, sheave and cables will be replaced. No work is planned on the other three towers, where the trunnions test OK.
But while the parts are being replaced, workers can't just order the lift span and counterweight, totaling about 1.6 million tons, to stay. Carl James, project manager for Christie Constructors, said a key step was to build a "falsework" tower to support the counterweight during the process.
Building that temporary tower, anchored to the bridge at eight places, was done in a series of nighttime road closures. Next Tuesday, when jacks above the counterweight pull it upward and lock it to the falsework, all traffic will be switched to the southbound bridge.
One of the tasks involves putting a new concrete coating on the base of the counterweight to prevent it from crumbling and falling on traffic in future years.
Once it's time to really mess with commuters, the process will go through several distinct steps:
TRAFFIC: Signs will be unwrapped, barriers moved into place and routes changed. That is expected to trigger a massive traffic jam, despite extraordinary efforts to boost mass transit and carpooling.
LIFT: Cable jacks above the counterweight will lift the mass of steel and concrete slightly.
UNHOOK: The 16 cables on each tower will be cut and lowered to a barge.
REPLACE: The now-empty sheave/trunnion assembly will be lowered to a barge, and the new assembly will be lifted into place. The old unit weighs an estimated 18 tons; the replacement is 6.5 tons heavier.
RECABLE: Sixteen prestretched wire cables -- half are 183 feet long, and the rest are 186 feet -- will be arranged on a dummy pulley on a barge, then lifted into place eight at a time. Two spare cables have been manufactured in case one gets damaged or dropped.
HOOKING UP: Giant new connectors have been machined to speed attaching the cables, which is a slow, tedious task, James said. Other jobs have taught the company that "reusable" connector pins often are corroded and impossible to use.
Then crews will repeat the process on the other side of the north tower, replacing cables, sheave and trunnion. Once that is completed, the counterweight will be lowered a few inches, and the traffic detours can end.
As soon as traffic is flowing again, the clock will stop, and Christie's bonus or penalty will be calculated. The target is 21 days, and the bonus is $100,000 a day and $1,000 for each additional hour that Christie beats the deadline. Of course, the company has similar penalties for being late.
Now the company says the closure probably will last seven to 10 days.
But stopping the bonus clock does not end the work. As long as the closures are at night, the company has as much time as needed to remove the falsework and the crane, according to Katy Tobie, spokeswoman for the Oregon Department of Transportation.
James said the bonus is reasonable because it is far less than the cost the detours will have on the region's economy. He also said the company spent extra money to shorten the road closure.
Because the replacement parts are not found on the shelf of a corner convenience store, James worried about getting the key components manufactured and shipped from the four corners of the nation. But he said that step went without a hitch.
It was that fear of the unexpected that led the Oregon Department of Transportation to locate and purchase a rare gear used on the bridge's lifting motor. If the old one is damaged, the replacement gear is ready.
And for the negative-thinkers who have complained about the job being done in less than 21 days, they can think of the closure as a practice run. The Interstate Bridge is tentatively scheduled to be closed in 1999 for repainting and in 2001 for replacement of electrical controls.
The cost of those two closures is expected to total $20 million, or almost five times what Christie Constructors is expected to pocket on this job.
Bill Stewart covers planning, transportation and public housing for The Oregonian's City Life Team. He can be reached by telephone at 294-7670, by fax at 294-5023, by e-mail at billstewart@news.oregonian.com, or by mail at 1320 S.W. Broadway, Portland, Ore. 97201.
I-5 Bridge fix planned in detailed segments