TriMet tells contractor to redo defective rail bridge
Issues with a concrete pour on light-rail construction through Milwaukie last week forced contractors to work backward by chipping out and replacing the defective portions of a railroad overpass.
Assuming they get the OK from TriMet, contractors will be pouring new concrete this week. TriMet officials, having promised the $1.49 billion line will open to the public in 2015, say that the two-week error will not delay the project overall.
You might have a defect where you might have to remove it, and that is a requirement of contractors on every project, so weve built in time for it, said TriMet spokeswoman Mary Fetsch. There may be at times quality-control issues that have to be fixed.
TriMet engineer John Lostra noted that subcontractor Cascade Bridge has been building the Tillamook Overpass on a yearlong $7 million contract. They still have another four months to go in the contract, and Lostra expects theyll remain on schedule with the rebuilding.
Theyre chipping on this defective portion, and theyll continue to chip until theyre to a place where they think they have gotten all the bad concrete chipped out, Lostra said. The concrete mix itself was perfectly fine, but a couple things added up not in their favor. It was a really hot day, and the concrete mix was not as fluid as they would have liked. As they place the concrete, they vibrate all the rebar to get it all in, and when they stripped off the forms, it was still porous.
Cascade Bridge representatives did not return calls for comment or to estimate their exact cost of reconstructing that portion of the bridge.
Although it was for the same light-rail bridge, a different subcontractor was responsible for the 173,000-pound concrete I-beam intended for Tillamook Overpass construction that fell onto Interstate 5 in April. A semi-truck carrying the concrete I-beam to the construction site overturned on the Marquam Bridge during rush hour, crushing a nearby car.
When the car caught fire, it forced a 14-hour closure of the bridge. TriMet officials said the Knife River subcontractor owned the girders and I-beams until they were delivered, inspected and approved, so taxpayers didnt have to pay for that mistake either.