SEATTLE — The Seattle Department of Transportation (SDOT) said steel inside concrete was stretched past its limit, causing foundational cracks in the West Seattle Bridge.
SDOT hosted a media tour Thursday of the progress to stabilize and repair the bridge for a mid-2022 reopening.
The West Seattle Bridge has been closed since March 2020 when crews deemed it unsafe.
“Although they designed this bridge with the standards of the time, it turned out to be not strong enough for the bridge to carry out its useful life as designed,” said Matt Donahue, Director of Roadway Structures Division for SDOT.
He continued, “Now that we know we want to repair it and put traffic back on it, we’ll put enough carbon fiber reinforced polymer and reinforced steel to have traffic back on the bridge."
Over the past year, crews have installed what amounts to 10 miles of steel wire to the bridge to add additional tension to each side. Crews say all that tension is working and has stopped existing cracks from spreading.
“To me, this is a maintenance and inspection success story. Because of our maintenance and inspection program, we were on the bridge doing our inspections, as were required to do, to catch that cracking when it started,” Donahue said.
Inside the bridge, SDOT is using sophisticated technology to monitor the cracks. Data from sensors is sent in real-time to engineers' cell phones.
“Design and testing are extremely important so that we only have to do this once. We wanted to get it right the first time so we want to make sure that we are hitting all the steps,” said Heather Marx of the West Seattle Bridge Safety Program.
SDOT said they are right on schedule to repair and reopen the West Seattle Bridge in mid-2022.