One of the 10 recently built bridge pillars on the Highway 520 project will be destroyed and rebuilt, because part of the concrete exterior was too thin, the state Department of Transportation says.
The pillars are formed by pouring concrete around a cylindrical cage of reinforcing bar, all contained within a temporary steel tube. When the tube was removed, some concrete peeled off with it. On further inspection, workers found the rebar cage had shifted during the pour, leaving less than the normal 1.5-inch concrete thickness around the rebar, said DOT spokeswoman Suanne Pelley.
Motorists will see the rebuild over the next day or few days. The flawed column is the northwesternmost of the 10 poured this fall, Pelley said Friday.
The contractor, Kiewit-General-Manson, is replacing the pillar at its own expense, DOT said. “KGM is implementing the quality assurance program that is a key component of our contract,” said Julie Meredith, Highway 520 program director, in a press release linked here.
Meanwhile, the construction team will pump out 2.5 million gallons of lake water next week from inside a metal cofferdam. This will clear space for a huge abutment to be built near the east shore.
Kiewit and partners are employing 832 workers doing $954 million in bridge and pontoon work at the lake, Kenmore, Tacoma and Grays Harbor. Earlier this week, the state acknowledged that it’s negotiating schedule changes with Kiewit, because early problems with cracked pontoons have jeopardized the state’s goal of finishing the project by December 2014. The contract allows a mid-2015 deadline, but Kiewit initially proposed to finish six months early and collect $2.5 million incentive pay.