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New 520 bridge components are being built in Kenmore

  • Written by Don Mann
Kenmore Site
Photo courtesy Aequalis Photography/WSDOT The KGM construction and staging area on Kenmore’s LakePointe property site.
Representatives from contractor Kiewit/General/Manson (KGM) and the Washington State Department of Transportation (WSDOT) held an open house Tuesday at Kenmore City Hall to discuss the construction of bridge components being built in Kenmore for the new State Route 520 floating bridge and to field questions from the public.

Several dozen citizens attended. KGM is leasing a portion of the LakePointe property (at 6525 N.E.  175th St.) as a construction yard and barge landing to manufacture precast deck panels — what will ultimately be the driving surface of the new bridge —as well as gravity and fluke anchors to hold it in place at the bottom of Lake Washington.

The 44-acre site is owned by Gary Sergeant of Pioneer Towing; KGM is utilizing approximately 14 acres.

KGM Planning Manager Dave Stegeman said the company will produce 776 concrete panels measuring 57 feet x 15 feet each that will comprise the 5600 feet span.

Eight gravity anchors weighing over 300 tons each — 587 tons when fully loaded with rock, he said — and 46 fluke anchors will be delivered to the new bridge site by barge.

The gravity anchors will be constructed on the barge itself, docked adjacent to the on-site wharf.

KGM has already begun production of 77 pontoons at an industrial site in Aberdeen. Some of the pontoons will be as long as 360 feet, as wide as 75 feet and as tall as 35 feet. Upon completion they will be towed by barge from Grays Harbor to the Pacific Ocean to the Strait of Juan De Fuca to Puget Sound through the Ballard Locks to its final destination in Lake Washington, WSDOT Project Director John White said.

“It’s a massive undertaking and watching them being towed two at a time through the Locks will be something to see.”

Other bridge components are being constructed at the Port of Tacoma, he said.

The new bridge will be 20 feet high above the water, 10 feet higher than the existing bridge, Stegeman said, and is scheduled to be up and running by 2015.

KGM will then disassemble and remove the old bridge.

Kenmore Mayor David Baker said the project will create about 50 family-wage union jobs and generate additional sales-tax revenue for the city. “It also means a major cleanup for that site which will ultimately make the property more attractive to developers.”

KGM has leased the LakePointe property for three years.

Sergeant has been trying to sell the parcel “for a long time,” Baker said. LakePointe development has been permitted by the city but has been delayed because of a sluggish economy. The property, which Baker said sits at the “crown of the lake,” has long been considered a lynchpin to future Kenmore development, with mixed residential and retail use projected.

The site, which sits atop landfill, has been an industrial yard since the mid 1970s, used for similar manufacturing, storage and concrete work projects. Much of the property in recent years had been overrun with stockpiled materials — soil, dredged material along with industrial and natural debris. In order to be permitted, KGM relocated the stockpiled material, regraded and updated drainage and erosion controls, replaced the gravel surface across the entire site and repaired the existing wharf.

Shoreline vegetation has been protected and the entire site will now drain to new sediment traps and not run off into the lake and river, satisfying the requirements of both the National Environmental Policy Act (NEPA) and the State Environmental Policy Act (SEPA).

New gas, water, power and communication lines have also been installed on the Kenmore site. The new six-lane floating bridge, a $4.65 billion project not yet fully funded, will replace the current bridge constructed in 1963 and showing its age: The bridge’s pontoons have become vulnerable to windstorms and its support columns are vulnerable to earthquakes.

Moreover, the existing bridge has only two lanes in each direction, no shoulders and no high-occupancy vehicle (HOV) lanes.

The new bridge, to be constructed on the north side of the old one, will include two additional general purpose lanes and one transit/HOV lane in each direction, wider shoulders to allow vehicles to pull over in case of breakdown, and a 14-foot wide bicycle and pedestrian path.

Bridge components will begin to be assembled and floated into place later this year.

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