Demolition of cracking 520 project column to begin soon
Nov 29, 2022, 5:11 AM | Updated: 5:13 am

A construction company needs to replace the SR-520 concrete pier cap that resides above I-5 in Seattle, which inspectors found to have cracks and holes during an October inspection. (Courtesy of WSDOT)
(Courtesy of WSDOT)
We found out earlier this month that a concrete column built just this year on the State Route 520 project is already crumbling and needs to be replaced.
The problem was obvious as soon as the wooden forms were removed from the pier in October. The concrete was breaking off. Re-bar was exposed. And the cracks were large. There was no doubt it would have to be rebuilt.
SR 520 ramp closed through February for vibration testing
“We’ve been working with the contractor on a rebuilding plan to determine the best possible way they can go out there and take that crossbeam down and rebuild it,” the Washington State Department of Transportation’s (WSDOT) Tony Black said.
Black said the column is fine. It’s the top cap that needs to be replaced. A demolition plan should get underway in a few weeks, and the entire rebuild should be done before the end of the year.
“It will likely take a few days, and it will likely be at night,” Black said.
I promised westbound 520 drivers that they would get their second lane to southbound Interstate 5 back early next year. Will this work delay that from happening?
“That lane reduction wasn’t just for the concrete pier,” Black said. “It was mostly for the work zone areas around there.” That lane restriction should be eliminated by the end of February.
The other big question is, who will pay for this mistake? WSDOT said the contractor will eat the cost.
New ‘ramp support’ over I-5 needs to be replaced
Just a reminder of what WSDOT is doing here. This column will help support a new concrete flyover ramp connecting the 520 and the I-5 Express Lanes. It will be a reversible lane that will switch with the express lanes. It will go westbound 520 to southbound I-5 in the morning and northbound I-5 to eastbound 520 in the afternoon.
It is scheduled to open in 2024, about the same time as the Montlake Lid project wraps up.
This reversible lane will begin as a bus-only lane, but it will convert to an HOV lane for all vehicles when the 520 connection to I-5 is complete in about nine years.
Check out more of Chris’ Chokepoints.