Lacey V. Murrow Memorial Bridge
Template:Short description Template:Use American English Template:Use mdy dates Template:Infobox Bridge
The Lacey V. Murrow Memorial Bridge is a floating bridge in the Seattle metropolitan area of the U.S. state of Washington. It is one of two floating bridges that carries Interstate 90 across Lake Washington from Seattle to Mercer Island. The Murrow Bridge carries four lanes of eastbound traffic, while westbound traffic is carried by the adjacent Homer M. Hadley Memorial Bridge.
The Murrow Bridge is the second-longest floating bridge in the world, at Template:Convert (the longest is the Governor Albert D. Rosellini Bridge–Evergreen Point, a few miles north on the same lake). The original Murrow Bridge opened in 1940, and was named the Lake Washington Floating Bridge. It was renamed the Lacey V. Murrow bridge in 1967.<ref>Lange, G. (1999). Lake Washington Floating Bridge is dedicated on July 2, 1940. Washington State Department of Transportation. http://www.historylink.org/File/682</ref> The original bridge closed in 1989;<ref name=lmtapfldw>Template:Cite news</ref><ref name=srfbrclp>Template:Cite news</ref> the current bridge opened in 1993.<ref name=fbopns>Template:Cite news</ref>
Along with the east portals of the Mount Baker Ridge Tunnel, the bridge is an official City of Seattle landmark and a National Historic Civil Engineering Landmark.<ref>Landmarks Alphabetical Listing for L Template:Webarchive, Individual Landmarks, Department of Neighborhoods, City of Seattle. Accessed December 28, 2007.</ref><ref>Template:Cite magazine</ref> While the bridge originally had an opening span at the center of the bridge to allow a horizontal opening of Template:Convert for major waterborne traffic, the only boat passages currently are elevated fixed spans at the termini with Template:Convert of vertical clearance.<ref name="Highways 1968">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.</ref>
History
The bridge was the brainchild of engineer Homer Hadley, who had made the first proposal in 1921.<ref>Template:Cite web</ref> 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 Eastside businessman Miller Freeman.<ref>Template:Cite news</ref><ref>Template:Cite news</ref><ref>Template:Cite book</ref> The proposed floating bridge was met with skepticism and was heavily criticized by The Seattle Times, which later issued an apology in a front-page edtiorial before it opened.<ref name="HistoryLink">Template:Cite web</ref><ref name="Reynolds">Template:Cite news</ref> Construction began on January 1, 1939, and was completed by the Washington State Toll Bridge Authority in 1940.<ref>Template:Cite web</ref> The project was partially financed by a bond issue of $4.184 million and the total cost, including approaches, was approximately $9 million.<ref name="Highways 1968"/> The bridge was built under a Template:Frac-year contract awarded to the Puget Sound Bridge and Dredging Company in the amount of $3.254 million.<ref>Template:Cite journal</ref>
The Lake Washington Floating Bridge opened on July 2, 1940, and carried a section of the Sunset Highway, then part of US 10 (later decommissioned and replaced by Interstate 90).<ref>Template:Cite news</ref><ref>Template:Cite news</ref> The existing Lake Washington ferries from Seattle to Mercer Island and Medina were both immediately discontinued, while the Seattle–Kirkland run remained in service. The Mercer Island and Medina ferries carried a total of 164,614 vehicles in 1939; a majority of traffic between Seattle and the east side of the lake was carried on other highways.<ref name="Report1940">Template:Cite report</ref> Bridge tolls of 25 cents for single-occupant automobiles, 35 cents to $2 for trucks, 10 cents for bicycles, 5 cents for pedestrians, and 35 to 50 cents for horse-drawn vehicles were collected at a toll plaza on Mercer Island.<ref name="Reynolds"/><ref name="Report1940"/> The tolls were removed on July 2, 1949, after the bonds had been paid off 19 years ahead of schedule.<ref>Template:Cite news</ref><ref>Template:Cite news</ref>
The bridge was renamed the Lacey V. Murrow Memorial Bridge in 1967.<ref name="HistoryLink"/> The eponymous Lacey V. Murrow Template:Nowrap 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, rising to the rank of Template:Nowrap Template:Nowrap graduate of Washington State College in Pullman, he was the oldest brother of CBS commentator Edward R. Murrow.<ref name=hlhwd/>
The original bridge 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 during morning and evening rush hours in an effort to alleviate 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 became essential and a parallel bridge, the Homer M. Hadley Memorial Bridge, was completed in 1989, and named for Hadley in 1993.Template:Cn With the opening of the new bridge, the 49-year-old Murrow Bridge closed on June 23, 1989, for renovation that was projected to take three years.<ref name=coobpro>Template:Cite news</ref><ref name="seatimes-1989jun22">Template:Cite news</ref><ref name="seattle-pi-1989jun23">Template:Cite news</ref> The bridge sank in a storm on November 25, 1990, during refurbishment and repair. There were no fatalities or injuries.<ref>Template:Cite news</ref>
1990 disaster
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.<ref>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.</ref> 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),<ref name=raincha>Template:Cite news</ref> 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 Template:Convert 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 Template:Nowrap 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 Template:Nowrap and it was closed for a short time afterward.<ref name=survibr>Template:Cite news</ref> Westbound traffic was allowed Template:Nowrap and eastbound traffic was resumed in early December.<ref name=bscspl>Template:Cite news</ref>
The disaster delayed the bridge's reopening by 14 months, to September 12, 1993.<ref name=fbopns/><ref name="last link of I-90">Template:Cite news</ref>
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 Template:Nowrap
See also
- Template:Portal-inline
- Template:Portal-inline
- Template:Portal-inline
- List of bridges documented by the Historic American Engineering Record in Washington (state)
- List of bridges in Seattle
- Homer M. Hadley Memorial Bridge
Notes
External links
- Template:Structurae
- Bridge Camera, includes some weather information
- Template:HAER
- King-5 television video of the sinking
Template:Washington State bridge disasters Template:Bridges of Seattle Template:Authority control
- Bridge disasters in the United States
- Bridge disasters caused by construction error
- Bridges in Seattle
- Bridges in King County, Washington
- Bridges completed in 1993
- Bridges completed in 1940
- Interstate 90
- Landmarks in Seattle
- Monuments and memorials in Washington (state)
- Historic Civil Engineering Landmarks
- Road bridges in Washington (state)
- Bridges on the Interstate Highway System
- Transportation disasters in Washington (state)
- Former toll bridges in Washington (state)
- 1940 establishments in Washington (state)
- Construction accidents in the United States
- Pontoon bridges in the United States
- Former National Register of Historic Places in Washington (state)
- Historic American Engineering Record in Washington (state)
- Concrete bridges in Washington (state)
- Mercer Island, Washington