Thank God for this. Not only do I work next to the freaking noisiest construction project ever, my bus would routinely be diverted on a long detour because of this bridge being closed. I wish they'd make some major bike improvements. Anybody know if they will put on bike lanes when they reopen the entire thing?
Burnside Bridge rehab ends with one last tweak
The $9 million job wraps this weekend with fine-tuning of the support system
Daily Journal of Commerce
POSTED: 06:00 AM PST Friday, January 4, 2008
BY LIBBY TUCKER
Downtown drivers rejoice. Multnomah County’s two-year rehabilitation of the Burnside Bridge wraps up this month as engineers do some final tweaking of the 82-year-old structure’s new lift system.
Most of the heavy lifting is complete on the $9 million project. Contractor Advanced American Construction Inc. has fixed a broken pin, which for years caused the east side of the span to open slower than the west side. The contractor also replaced the concrete deck and gave it a new coat of paint, all while leaving two lanes open for cars most of the time.
The bridge is already safe to drive on. But a little fine-tuning is needed to ensure the bridge doesn’t get out of whack again.
“It’s like a dentist doing a final adjustment on a new filling,” Chuck Maggio, a project manager for Multnomah County, said. “You can still eat with it, but over time, it can be sore to eat with it.”
The county will close the bridge to traffic tonight and Monday and again next weekend as the contractor measures, shims and jacks the metal arms and concrete pedestals the bridge rests on.
The bridge sections operate like a teeter totter, with a 3.5-million-pound concrete counterweight on one side and the 2-million-pound bridge span on the other side.
To make final adjustments, engineers will first measure the torque on the bridge’s weight-bearing parts. Based on the calculations, they’ll shorten and lengthen the link arms that guide the bridge’s counterweight when it opens and closes, raise and lower the live-load shoes where the bridge’s concrete deck rests, and balance the span by adding or removing concrete blocks to the counterweight.
The adjustments will be minute, measuring less than an eighth of an inch or a few extra pounds. But the force of that much concrete behind a hairline space can mean the difference between a bridge that ages gracefully and one in need of continual maintenance.
“For as massive as (the bridge) is, it’s very sensitive to small changes,” Kainan Bodenlos, job superintendent with Advanced American, said.
It’s the second time Advanced American will carry out the balancing operation; the same adjustments were made on the bridge’s west side last year. So Bodenlos expects the tune-up to run much more smoothly than the first time.
Once the adjustments are complete, the county will close the bridge twice more – at the end of the month and later in the spring — to open all five lanes to traffic and paint new lane markers.
The project, originally scheduled for completion on Dec. 31, was delayed due to Portland’s two-week holiday moratorium on downtown construction, according to Multnomah County. The county suspended its construction contract with Advanced American for the length of the moratorium, which racked up about $5,000 in additional project costs related to traffic control and equipment rentals.
But the extra cost is small compared to the cost of avoiding a $200 million bridge replacement. The old lift held out for 80 years, and engineers hope the new system will go the same distance, Bodenlos said.