520 Bridge Updates: Bridge Cables Repaired, Old Evergreen Point Overpass Demolished

This weekend closure on State Route 520 was a busy one, as crews repaired two damaged floating bridge cable connections found last week, and crews demolished the first of three old overpasses to be replaced.

Until the bridge is reopened, which is slated to be at 5 a.m. Monday, drivers will have to find another way across or around Lake Washington, according to the Washington State Department of Transportation.

WSDOT officials at the 520 Bridge on Saturday said that the next closure is slated for April, though the date hasn't been finalized, and that drivers can expect one closure a month through the end of the year.

Cable Damage Repaired

Two damaged State Route 520 floating bridge cable connection found last week were repaired this weekend. 

On Saturday, March 10, divers removed and replaced a broken bolt and damaged pin on the southeast anchor cable, an operation made more difficult because the work took place in water 60 feet deep, according to a Washington State Department of Transportation press release.

That competes the emergency work on the damaged anchor cable connections, which is expected to cost the state $60,000, according to the press release.

The cables under the bridge are what hold the floating bridge in place, said WSDOT Bridge Superintendent Archie Allen.

The first damaged pin connection was discovered during a routine inspection Thursday on the west end of the floating bridge, the state reported.

The pin is one of 58 that tie the 1.5-mile-long floating bridge to the Lake Washington lakebed. Working in 30-foot deep water, divers repaired that connection by Friday afternoon. 

As a precaution, bridge engineers inspected three other similar anchors and found the same problem on one additional connection at the east end of the bridge. Two other locations were inspected and did not have the same damage, the state reported. 

The repairs came ahead of the high winds expected on Sunday, which was good news, Allen said.

“We’re looking at gusts of 35-40 miles per hour on the lake. Those are the kinds of winds that put pressure on these pins,” he said in a prepared statement.

One-third of the floating bridge anchor cables are inspected every two years, and 15 of the 58 were replaced in 2010. Corrosion was initially suspected as the cause of the damaged pin connections.

Though the bridge is , the state said that immediate repairs were necessary because engineers said connecting pins tying together anchor cables and anchors already had slid partially out of position.

If a pin was forced completely out, separating the bridge and cable from the anchor on the lakebed, it would reduce the bridge’s ability to withstand large storms, state engineers said.

While a final determination is pending, bridge engineers now say it appears that the steel hardware connections were bent by forces produced by wind and wave action on the lake, the state reported.

Old Evergreen Point Road Overpass Demolished

The Evergreen Point Road Overpass, the narrow two-lane overpass that connected Medina and Hunts Point, is history, after the Washington State Department of Transportation .

The overpass gave way to the a new, wider , which will eventually include a Park and Ride, green space, access to transit and a wider road, according to the state. Traffic was rerouted over the new lid earlier this month.

Once the old two-lane overpass, which was built in 1962, is gone, crews will work on building new concrete supports for the new Evergreen Point Road lidded overpass, which will be completed during the next 18 months, according to the Department of Transportation.

When complete the , said Brian Dobbins, construction engineer for the Washington State Department of Transportation’s SR 520 Eastside Transit and HOV Project.

Drivers can expect at least one closure a month through the end of the year, he said. Upcoming closures will see the demolition of overpasses at 92nd and 84th streets, he said.

Dobbins said that the concrete and steel used for the old overpass will be sorted, recycled and sold.

"Every part will be recycled. Every part has value," he said.

The lids are part of the state's . Improvements include landscaped lids over portions of 520, a wider roadway, increased carpool lanes, a bicycle and pedestrian lane and environmental upgrades. The construction between Evergreen Point Road to east of 108th Avenue NE in Bellevue will cost $306 million.