Lacey V. Murrow Memorial Bridge

The Lacey V. Murrow Memorial Bridge is in the northwest United States, one of the Interstate 90 floating bridges that carries the eastbound lanes of Interstate 90 across Lake Washington from Seattle to Mercer Island, Washington. Westbound traffic is carried by the adjacent Homer M. Hadley Memorial Bridge (1989).

Lacey V. Murrow Memorial Bridge
The Lacey V. Murrow Memorial Bridge (right) and the Homer M. Hadley Memorial Bridge (left), looking east toward Mercer Island
Coordinates 47°35′24″N 122°16′12″W
Carries I-90, eastbound lanes
CrossesLake Washington
LocaleSeattle / Mercer Island, Washington, USA
Maintained byWashington State DOT
Characteristics
DesignPontoon bridge
Total length6,620 ft (2,020 m)
History
OpenedJuly 2, 1940
RebuiltSeptember 12, 1993

The Murrow Bridge is the second-longest floating bridge on Earth at 6,620 ft (2,020 m); the longest is the Governor Albert D. Rosellini Bridge—Evergreen Point (2016, original: 1963), a few miles north on the same lake. The third-longest is the Hood Canal Bridge, about thirty miles (50 km) to the northwest. The original Murrow Bridge opened in 1940 and was called the Lake Washington Floating Bridge. It was renamed the Lacey V. Morrow bridge in 1967.[1] The original bridge closed in 1989;[2][3] with the current bridge opening in 1993.[4]

Along with the east portals of the Mount Baker Ridge Tunnel, the bridge is an official City of Seattle landmark.[5] While the bridge originally had an opening span at the center of the bridge to allow a horizontal opening of 202 feet (62 m) for major waterborne traffic, the only boat passages currently are elevated fixed spans at the termini with 29 feet (8.8 m) of vertical clearance.[6]

History
Construction of the bridge; photo taken one year after start of construction.

The bridge was the brainchild of engineer Homer Hadley, who had made the first proposal in 1921.[7] The bridge came about after intensive lobbying, particularly by George Lightfoot, who came to be called the "father of the bridge." Lightfoot began campaigning for the bridge in 1930, enlisting the support of Miller Freeman.[8][9][10] Construction began January 1, 1939 and was completed in 1940.[11] The construction cost for the project, including approaches, was approximately $9 million. It was partially financed by a bond issue of $4.184 million.[6] Opened July 2, 1940, the bridge carried US 10 (later decommissioned and renamed Interstate 90). Tolls were removed in 1949.[12] The bridge sank in a storm on November 25, 1990 while it was undergoing refurbishing and repair.[13] The current bridge was built in 1993. The eponymous Lacey V. Murrow (1904–1966) was the second director of the Washington State Highway Department and a highly decorated U.S. Air Force officer who served as a bomber pilot in World War II and rose to the rank of brigadier general.[14][15][16] A 1925 graduate of Washington State College in Pullman, he was the oldest brother of CBS commentator Edward R. Murrow.[16]

The original bridge was built under a ​1 1⁄2-year contract awarded to the Puget Sound Bridge and Dredging Company (the project was led by engineer Peter John Jensen) in the amount of $3.254 million.[17] It included a movable span that could be retracted into a pocket in the center of the fixed span to permit large boats to pass. This design resulted in a roadway "bulge" that required vehicles to swerve twice across polished steel joints as they passed the bulge. A reversible lane system, indicated by lighted overhead lane control signals with arrow and 'X' signs, compounded the hazard by putting one lane of traffic on the "wrong" side of the bulge at different times of day in an effort to alleviate rush-hour traffic into or out of Seattle. There were many serious collisions on the bridge. The problems grew worse as the traffic load increased over the years and far outstripped the designed capacity. Renovation or replacement was essential and a parallel bridge, the Homer M. Hadley Memorial Bridge, was completed in 1989, and named for Hadley in 1993.

With the opening of the new bridge, the 49-year-old Murrow Bridge closed on June 23, 1989, for renovation work that was originally projected to take three years.[18][19][20]

1990 disaster
View northeast of bridge, west approach and Mount Baker Tunnel

On November 25, 1990, while under re-construction, the original bridge sank because of a series of human errors and decisions. The process started because the bridge needed resurfacing and was to be widened by means of cantilevered additions in order to meet the necessary lane-width specifications of the Interstate Highway System. The Washington State Department of Transportation (WSDOT) decided to use hydrodemolition (high-pressure water) to remove unwanted material (the sidewalks on the bridge deck). Water from this hydrodemolition was considered contaminated under environmental law and could not be allowed to flow into Lake Washington.[21] Engineers then analyzed the pontoons of the bridge, and realized that they were over-engineered and the water could be stored temporarily in the pontoons. The watertight doors for the pontoons were therefore removed.

A large storm on November 22–24 (the Thanksgiving holiday weekend),[22] filled some of the pontoons with rain and lake water. On Saturday, November 24, workers noticed that the bridge was about to sink, and started pumping out some of the pontoons; on Sunday, November 25, a 2,790-foot (850 m) section of the bridge sank, dumping the contaminated water into the lake along with tons of bridge material. It sank when one pontoon filled and dragged the rest down, because they were cabled together and there was no way to separate the sections under load. No one was hurt or killed, since the bridge was closed for renovation and the sinking took some time.[2][3] All of the sinking was captured on film and shown on live TV. The cost of the disaster was $69 million in damages. A dozen anchoring cables for the new Hadley bridge were severed,[18][23] and it was closed for a short time afterward.[24] Westbound traffic was allowed on Tuesday,[25] and eastbound traffic was resumed in early December.[26]

The disaster delayed the bridge's reopening by 14 months, to September 12, 1993.[4][27]

Precedents and lessons learned

WSDOT had lost another floating bridge, the Hood Canal Bridge, in February 1979 under similar circumstances. It is now known that the other major floating bridge in Washington, the Evergreen Point Floating Bridge, was under-engineered for local environmental conditions; that 1963 bridge was replaced with a new floating span in 2016.[28]

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See also

Notes
  1. Lange, G. (1999). Lake Washington Floating Bridge is dedicated on July 2, 1940. Washington State Department of Transportation. http://www.historylink.org/File/682
  2. Costello, Nancy (November 26, 1990). "Flood waters send bridge to bottom". Lewiston Morning Tribune. Associated Press. p. 1A.
  3. "Floating bridge collapses after storm hits". Spokesman-Review. Associated Press. November 26, 1990. p. A1.
  4. "Floating bridge opens". Spokesman-Review. Associated Press. September 13, 1993. p. A12.
  5. Landmarks Alphabetical Listing for L Archived July 21, 2011, at the Wayback Machine, Individual Landmarks, Department of Neighborhoods, City of Seattle. Accessed December 28, 2007.
  6. Tudor Engineering Company for Washington State Highway Commission Department of Highways. Legislative Reconnaissance and Feasibility Report "Lake Washington Bridge Crossings, Parallel Evergreen Point Bridge, North Lake Bridge. December 1968.
  7. Burrows, Alyssa (January 18, 2005). "Homer Hadley formally proposes a concrete pontoon floating bridge across Lake Washington on October 1, 1921". HistoryLink. Retrieved September 19, 2015.
  8. "G. W. Lightfoot Taken By Death". The Seattle Times. April 18, 1941.
  9. Reynolds, Peggy (May 24, 1989). "George Lightfoot's Vision Spanned Lake Washington". The Seattle Times. p. H1. Retrieved September 19, 2015 – via NewsBank.
  10. Brahm, Jane Meyer (2013). Mercer Island History: From Haunted Wilderness to Coveted Community. Island Books.
  11. Zylstra, Brian (January 28, 2011). "Building the first Lake Washington floating bridge". From Our Corner. Washington Office of the Secretary of State. Retrieved September 19, 2015.
  12. "Floating Bridge Pays For Itself". The Southeast Missourian. Newspaper Enterprise Association. July 19, 1949. p. 3. Retrieved May 18, 2010 – via Google News Archive.
  13. "Pontoon Bridge Sinks in Flooding As Seattle Is Battered by Storms". The New York Times. Associated Press. November 26, 1990. Retrieved September 19, 2015.
  14. "Gen. Lacey Murrow found dead in hotel". Spokane Daily Chronicle. December 17, 1966. p. 3.
  15. "Brigadier General Lacey Van Buren Murrow". United States Air Force. (Biographies). Retrieved August 8, 2018.
  16. Oldham, Kit (March 16, 2005). "Lacey V. Murrow becomes Director of Highways on March 20, 1933". History Link. (Essay 7278). Retrieved August 8, 2018.
  17. Schmitt, F.E. (January 5, 1939). "Low Bidder Get Contract on Pontoon Bridge". Engineering News-Record. New York: McGraw-Hill Publishing Company. 122 (1): 5. Retrieved December 28, 2008 – via Google Books.
  18. "Contractor on old bridge goes after big projects". Spokesman-Review. Associated Press. December 1, 1990. p. A8.
  19. Gough, William (June 22, 1989). "That'll be one bridge – to go – The old I-90 closes tomorrow". The Seattle Times. p. A1. Retrieved May 16, 2018 – via NewsBank.
  20. "Eastbound I-90 lanes to close over weekend in shift to new bridge". The Seattle Post-Intelligencer. June 23, 1989. p. B1. Retrieved May 15, 2018 – via NewsBank.
  21. Donald O. Dusenberry, et al. (Feb. 1995). "Failure of Lacey V. Murrow floating bridge, Seattle, Washington." Journal of Performance of Constructed Facilities, v. 9, n. 1, p 4-23.
  22. Cabrera, Luis (November 26, 1990). "Record rains create chaos in parts of western Washington". Lewiston Morning Tribune. Associated Press. p. 6A.
  23. "I-90 bridge opened and shut and..." Spokane Chronicle. Associated Press. November 29, 1990. p. A1.
  24. Costello, Nancy (November 27, 1990). "Surviving I-90 bridge still at mercy of wind". Spokesman-Review. Associated Press. p. A1.
  25. "Crews rush to anchor I-90 bridge". Spokesman-Review. Associated Press. November 28, 1990. p. B1.
  26. Rosenwald, Lonnie (December 3, 1990). "Bridge still creates splash". Spokane Chronicle. p. A6.
  27. "SR 520 - Floating Bridge and Landings Project". Washington State Department of Transportation. Retrieved September 19, 2015.

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