The 520 floating bridge will be closed this weekend as Washington State Department of Transportation (WSDOT) maintenance crews inspect and make repairs to the aging structure to make sure it will continue to carry traffic safely through winter weather. While the bridge is closed, drivers should allow extra time to travel across or around Lake Washington during the work.

The annual weekend bridge closure starts at 11 p.m. Friday, Aug. 20, and the bridge will reopen by 5 a.m. Monday, Aug. 23. The closure extends from Montlake Boulevard in Seattle to 92nd Avenue NE on the Eastside.

During the closure, WSDOT bridge engineers will conduct in-depth mechanical and electrical inspections on the main power supply to the bridge and the mechanical systems. Bridge engineers also will perform ultrasonic testing to analyze the condition of the drawspan’s steel vertical guide rollers. The guide rollers are a key part of the drawspan and are used to open and close the bridge for vessels or to relieve pressure on the bridge during heavy winds.

“These in-depth inspections and preventative maintenance will make sure the bridge is ready for another storm season,” said WSDOT Bridge Superintendent Archie Allen. “If any problems are identified, we have a couple of months to correct them before winter weather sets in.”

Crews also will clean, lubricate and repair the drawspan tracks, clean out drains, repair electrical cover plates, and perform preventative maintenance on the swing gates at mid-span.

“These systems must operate properly so that during a storm we can quickly open the drawspan and protect the bridge from damage,” Allen said.

Inspection results will be available in coming months.

Drivers should plan ahead for the closure as there are a number of events around the area this weekend. Two are at 7 p.m. Saturday, Aug. 21: a Seahawks pre-season game at Qwest Field; a Seattle Storm game at KeyArena.