ASCE History and Heritage International Landmark Nomination for:
Lacey V. Murrow Memorial Bridge
and Mount Baker Ridge Tunnels
Lacey V. Murrow Floating Bridge, Dec. 12, 1974. WSDOT Photo Collection, Washington State Archives.
Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
Table of Contents
Reference Letter from American Society of Civil Engineers, Seattle Section
Statement of Support from the Washington State Department of Transportation
Historic Civil Engineering Landmark Nomination ___________________________ 1
1. Date of construction (and other significant dates) ________________________ 1
2. Key civil engineers and other professionals associated with project __________ 4
3. Historic international, national, or local significance of this landmark ________ 11
4. Comparable or similar projects in the United States and other countries _____ 14
5. Unique features or characteristics which set this proposed landmark apart
from other civil engineering projects__________________________________ 15
6. Contribution which this structure or project made toward the development
of the civil engineering profession and the nation or a large region thereof____ 18
7. Published references concerning this nomination _______________________ 19
8. A list of additional documentation in support of this nomination. ____________ 21
9. The recommended citation for History and Heritage Committee
consideration. ___________________________________________________ 28
10. A statement of the owner’s support of the nomination. ___________________ 29
Appendices
A. Plan and Profile of the Floating Bridge_______________________________ A-3
B. Plan and Profile of Mount Baker Ridge Tunnels _______________________ A-7
C. 50th Anniversary of Lacey V. Murrow Floating Bridge ___________________ A-9
D. Article “Eighth Wonder of the Highway World… The Lake Washington
Floating Bridge” _______________________________________________ A-17
E. Homer M. Hadley Report on Proposed Bridge Across Lake Washington at
Seattle ______________________________________________________ A-25
F. Article “World’s First Draw Pontoon” _______________________________ A-35
G. Article “The Transition Section” ___________________________________ A-37
H. HAER Report on the Lacey V. Murrow Memorial Bridge _______________ A-39
I.
HAER Report on the Mount Baker Ridge Tunnel _____________________ A-61
J. Article “Twin Tunnels Driven Through Clay for Lake Washington Bridge
Project.” _____________________________________________________ A-77
Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
Statement of Support from the Washington State Department of
Transportation
Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
Historic Civil Engineering Landmark Nomination
1. Date of construction (and other significant dates)
The Lacey V. Murrow Memorial Bridge and the Mount Baker Ridge tunnels were
completed in 1940 to carry traffic for US Highway 10 (later Interstate 90) across Lake
Washington between Seattle and Mercer Island. The vicinity map in Figure 1 and the
detail map in Figure 2 illustrate the area. Prior to these improvements, travelers
between Seattle on the west side of the lake and communities on the east side relied on
dangerous and time-consuming two-lane roads around Lake Washington. The lake is 20
miles long and up to 4 miles wide. In 1923, the East Channel Bridge was built of timber
and steel to connect Mercer Island with the region’s eastern communities. This inspired
the public’s imagination to continue west across the lake, creating a direct route between
Mercer Island and Seattle. 1
The final bridge solution resulted in the largest floating structure in the world at the time it
was constructed, spanning 1.5 miles of water as part of a project 6.5 miles in length. 2 It
surmounted the obstacles of Lake Washington’s 200-foot water depth plus the 200-foot
depth of soft soil at the lake bottom and the 260-foot high Mount Baker Ridge along the
lake’s edge in Seattle. It was the first floating bridge in the world built of reinforced
concrete.2 The bridge also included the first floating concrete sliding drawbridge. 3 The
project included twin soft-bore tunnels through the Mount Baker Ridge, which were the
largest diameter in the world at the time of construction. 4
Lacey V. Murrow Bridge Project, DOT Photo Collection, Washington State Archives.
Figure 1: Vicinity Map (Circa 1935)
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
Engineer Homer M. Hadley originally developed the concept of the concrete floating
bridge in its current location in 1920. In 1937, it was Lacey V. Murrow, Director of
Highways and Chief Engineer of the Washington State Toll Bridge Authority (WTBA),
who made the decision to use Hadley’s idea to cross Lake Washington. Mr. Murrow was
instrumental in forging ahead amid heavy public scrutiny of this innovative idea. 5
Ground was broken for bridge and tunnel construction on December 29, 1937, and both
aspects of the project were completed in time for opening day on July 2, 1940.1, 5
According to a Washington State Department of Transportation (WSDOT) press release,
the first toll was paid on July 2, 1940, and the final toll was paid nine years later to the
day—and 19 years earlier than the 1968 date projected for retiring the Public Works
Administration (PWA) revenue bonds. In 1981, the 875-feet long floating drawbridge was
replaced with a straight span of roadway. 6
A parallel bridge 60-feet to the north was built in 1989 to meet increased traffic demand.
After serving traffic for fifty years, the original floating bridge was then closed for
renovation. After the renovation, the original bridge would have served as the bridge for
the eastbound traffic, while the westbound traffic used the new north bridge and tunnel.
However, during heavy rain and wind on November 22-23, 1990, waves and stormwater
heavily flooded a center pontoon that sank and rendered many of the adjacent bridge
pontoons unusable. 7 The bridge failed due to unfortunate problems and events during
the renovation effort.
Lacey V.
Murrow Bridge
Lake Washington
Bellevue
I-90
Mount Baker
Ridge Tunnels
Adapted from King County iMap, Hydrographic information, 2007.
Figure 2: Detail Map of Lake Washington
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
In 1993, new pontoons were constructed and the new eastbound bridge began carrying
traffic. The replacement structure uses the original tied arch spans and anchor piers.
The two approaches to the transition spans were split in the center and widened with a
new deck to preserve the character of the original bridge.1 The reconstructed bridge was
opened to traffic on December 12, 1993. The original tunnels are still in use today. The
National Society of Professional Engineers (NSPE) awarded the bridge its national
“1993 Outstanding Achievement Award” for its innovative design and contribution to
society. 8
1
Holstein, Craig and Hobbs, Richard. Spanning Washington. Pullman: Washington State
University Press, 2005, p. 172.
2
“Lacey V. Murrow Memorial Bridge.” Historic American Engineering Record No. WA-2, p. 7.
3
Andrew, Charles. “Eighth Wonder of the Highway World…The Lake Washington Floating
Bridge.” Pacific Builder and Engineer 46 (July 6, 1940): p. 33.
4
Mount Baker Ridge Tunnel, Historic American Engineering Record No. WA-109, p. 8.
5
McDonald, Lucile. “The Inspiration for the First Floating Bridge.” Seattle Times (July 26, 1964).
6
“I-90 Bridge Bulge to be Replaced Over Labor Day Weekend (Sept. 4-8).” WSDOT press
release, Washington State Department of Transportation (WSDOT and State Department of
Highways) Records, Washington State Archives, Olympia, WA., August 17, 1981.
7
Engstrom, John. “Our Hearts Sank.” Seattle Post-Intelligencer (December 20, 1990).
8
“New Lacey V. Murrow Bridge Named Outstanding Engineering Achievement.” WSDOT press
release, Washington State Department of Transportation (WSDOT and State Department of
Highways) Records, Washington State Archives, Olympia, WA (January 12, 1994).
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
2. Key civil engineers and other professionals associated with project
Homer M. Hadley
Homer M. Hadley was a young engineer working in the Seattle School District
architect’s office when, in 1920, he came up with the idea of using concrete pontoons
to float a roadway across Lake Washington. He had previously worked in a
Philadelphia concrete shipyard where concrete barges were built for World War I
applications to the Emergency Fleet Corporation.5
Mr. Hadley tried to finance the concept as a private toll project during the period from
1921 up to the Great Depression in 1929. 9 In March 1937, the State of Washington
created the Washington State Toll Bridge Authority. As recorded in his diary that year
on June 10, Mr. Hadley introduced the idea of a pontoon bridge and tunnel for
downtown Seattle to Lacey V. Murrow. Mr. Murrow, who was Chief Engineer of the
Washington State Toll Bridge Authority, endorsed this concept promptly after the
meeting. This decision came just prior to preparation of final construction documents
for a fixed bridge crossing. That proposed “South Mercer Island Bridge” was to be
located at the southern tip of Mercer Island, approximately three miles south of the
floating bridge site, and would have connected with Seattle’s Seward Park area. The
more direct corridor to Seattle that Mr. Hadley proposed was located instead on the
north end of Mercer Island. 5
Mr. Murrow tried to retain Mr. Hadley as a consultant from the Portland Cement
Association, where he was employed. However, Mr. Hadley’s association with the
cement industry became too great an obstacle. The project involved state and
federal funds and the idea of a floating bridge made of concrete was seriously
contested. His involvement would have been seen as a conflict of interest. 5
Shortly after Mr. Murrow’s death in 1967, the name of the bridge was changed from
the “Lake Washington Floating Bridge” to the “Lacey V. Murrow Memorial Bridge.”
Mr. Hadley’s name was not given to the bridge because of his association with the
Portland Cement Association. However, in July 1993, his name was given to the
new, parallel floating bridge for westbound traffic, the Homer M. Hadley Memorial
Bridge. 10
Homer More Hadley (1885-1967), Engineer
Engineer Homer M. Hadley designed several unique concrete
bridges throughout the state of Washington during his lifetime,
including many early American applications of the European
innovation of concrete hollow-box, or cellular construction.
This economical method of construction was used extensively
throughout Europe, but was not widely used in the United
States until the 1940s and 1950s. It was Hadley who originally
conceived the design of a floating bridge across Lake
Washington, the large lake that separates Seattle from
Bellevue and Kirkland (the Eastside). He visualized a floating
roadway made up of a series of hollow concrete barges.
Homer Hadley's unusual work reveals the effects of a single
innovative engineer on bridge design within the state.
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
Hadley was born in Cincinnati, Ohio, and raised in Toledo. He worked as a surveyor in
North Dakota, and came west as part of the U.S. Coast & Geodetic Survey. Before
settling in Seattle, he worked on a surveyor crew for the Great Northern Railroad, Copper
River Railroad in Alaska, and for the Canadian Northern Railroad in Vancouver. He
studied engineering intermittently at the University of Washington, attaining the
equivalent of about three years of study.
Hadley was experienced in building concrete ships and barges in Philadelphia during
World War I for the Emergency Fleet Corporation. As would happen during and after
World War II, steel shortages forced the Government to seek alternate sources of
materials for use in shipbuilding. In 1920, as a young engineer working in the
architectural office of the Seattle School District, Hadley suggested a floating bridge
across Lake Washington, supported by concrete pontoons.
Hadley formally proposed his idea at a meeting of the American Society of Civil
Engineers on October 1, 1921. Hadley's proposal caused considerable debate. Skeptics
included Seattle civic leaders, The Seattle Times, and the Lake Washington Protective
Association. Even the Navy, with its station at Sand Point, opposed the idea, citing
aesthetic considerations. He had hoped to build the bridge as a toll bridge with private
money, but bankers ridiculed the idea, calling it "Hadley's Folly."
In 1921, Hadley took a job with the Portland Cement Association, promoting the
increased use of cement for large-scale projects. He was sent to Japan in 1923 after the
Great Kanto earthquake to study the effects on different types of structures.
Hadley continued to dream about the creation of the bridge for the next 10 years. While
highly critical of Franklin Roosevelt's politics, he nonetheless went to see Lacey V.
Morrow (brother of famous radio and television journalist, Edward R. Murrow), director of
the State Department of Highways, when federal monies became available to the states
in the depth of the Great Depression. Morrow was intrigued by the concept and his staff
verified that the design was feasible.
In the mid-1930s, Homer Hadley designed one of the first paving machines in the United
States. At the time, a prototype laid a strip of pavement on the highway to Orting,
Washington.
In the 1930s Hadley had also become well established with the Portland Cement
Association, a fact that caused Murrow to encourage Hadley to step out of the limelight of
the floating bridge project, now underway. Murrow was concerned that the Association's
motto, "to extend and promote the uses of concrete," would cause the opposition factions
to paint Hadley as having ulterior motives for promoting his design. Murrow assured
Hadley that he would be given credit for his contribution — a promise he was not to keep.
A biography of Homer Hadley, written by his son Richard (d. 2002) in 1967, claims that
Homer Hadley designed the first concrete box-girder bridge in the United States. The
bridge cited is the Mashall Bridge (Pierce County Bridge #24164-A) near Eatonville.
Further research may be required to verify this claim, based on a letter from Homer
Hadley to Pierce County road engineer, Keith Jones. The letter is dated September 10,
1962, and in it Hadley himself addresses the issue by stating, "which I believe is the first
concrete box-girder bridge in the United States."
Hadley's floating bridge design was in response to Seattle's immensely challenging water
barrier to the east of the city — deep, glacially carved Lake Washington. The design of
the Mercer Island Bridge (also called Lake Washington Floating Bridge) was considered
radical, but was approved in 1937, and opened in 1940 to rave reviews.
The bridge paved the way for development of the Eastside. In 1967, the bridge was
renamed after Lacey V. Murrow. In 1993, Seattle's Mortar Board Alumni (University of
Washington) led a successful statewide effort to name the newest Lake Washington
floating bridge for Homer Hadley. The campaign was unanimously approved by the state
legislature.
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
Similar designs were utilized for other floating bridges to come. In 1963, the second
floating bridge across Lake Washington was opened. The Evergreen Point Bridge carries
Route 520 from Montlake to Evergreen Point. In 1961, the Hood Canal Bridge opened,
carrying Route 104 from the Olympic Peninsula to the Kingston ferry landing, bridging
Jefferson and Kitsap counties. The latest floating bridge, running parallel to the original
was opened in 1989, and named for Homer Hadley.
Giving up a lifelong pension within only four years of retirement, Homer Hadley struck out
on his own as a private engineering consultant in 1947. His son Richard joined him soon
thereafter, and the pair designed several buildings in Juneau, Alaska, in the late 1950s
and early 1960s. Hadley had brought his experience of Kanto to bear, and all his
buildings survived the Alaska earthquake of 1964, which measured 9.4 on the Richter
scale.
As a member of the Earthquake Committee, Seattle Section, American Society of Civil
Engineers (ASCE), Hadley participated in reporting and making recommendations on the
1949 Pacific Northwest earthquake.
In 1955, Hadley designed a bridge that would set a national precedent. Hadley described
the design initially as a "tied-cantilever" but the significance would be recognized later as
it became a prototype for what would be called "cable-stayed" bridges. This is a bridge in
which the superstructure is supported by cables or stays attached to a tower or towers
located at the main pier(s).
Moving into the design of steel bridges later in his career, Hadley designed the Parker
River Bridge, which was erected over the Yakima River between Benton City and Kiona.
In 1962, the Iron and Steel Institute (AISC) awarded the bridge First Prize for "the most
beautiful bridge of its class in the United States." His steel "delta girders" were the subject
of the feature article in the May 1966 issue of Civil Engineering.
Homer M. Hadley worked up until his death in July 1967. He died unexpectedly at his
summer home at Soap Lake.
(Reprinted from HistoryLink.org Essay 5419 by Phillip Seven Esser [March 14, 2003]
http://www.historylink.org/essays/output.cfm?file_id=5419. See the online entry for a list of sources.)
Lacey V. Murrow
Lacey V. Murrow was Director of Highways in Washington State from 1933 to 1940
and was Chief Engineer of the WTBA when it was created in 1937. The WTBA was
set up to meet federal Public Works Administration (PWA) requirements. The
authority was given sole power over the design, location, and financing for a Lake
Washington bridge. 11
WTBA followed on the heels of the Seattle Toll Bridge Company, which had been
working since 1930 on developing the 3,400-foot steel truss cantilever from the south
shore of Mercer Island to Seattle’s Seward Park. The cantilever bridge was chosen
after hearings held by the City of Seattle to evaluate four alternative bridges to cross
the lake in 1931, including a pontoon bridge suggested by Hadley. Newspapers
eventually took sides and fought against any bridge crossing the lake, but particularly
against a pontoon bridge that they envisioned as a series of scows chained
together.1 However, the Seattle Toll Bridge Company had trouble finding investors to
fund a $3.5 million cantilever bridge during a slow bond market. Impatient with the
slow progress, in 1935, King County began, and nearly completed, design of the
bridge, but the county also had trouble with financing the construction. In 1937, the
state legislature took over the financing, design, and construction of the toll bridge
itself by creating the WTBA.
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
When Mr. Murrow made the decision to use Hadley’s idea of a floating bridge to
cross Lake Washington in June 1937, he formed a board of four eminent bridge
consulting engineers, which included Charles E. Andrew, Reginald H. Thomson, R.
B. McMinn, and Luther E. Gregory. The board approved the preliminary design of the
floating bridge on February 26, 1938, after four months of study. The Seward Park
Community Club and the Lake Washington Protective Association put up a fight
against the floating bridge concept. The Association maintained that the bridge would
sink within five years. The project was deemed “a financial folly, an unnecessary tax
burden and a desecration of the lake.”5 Preservationists did not want a bridge
altogether—it could ruin property values, bring heavy traffic into their neighborhoods,
hurt the view; and fence off the lake. The U.S. Navy protested that a floating bridge
might interfere with navigation and seaplanes using its base on Lake Washington at
Sand Point.
Mr. Murrow had little time to work with public opinion to get approval for a floating
bridge. Governor Clarence Martin promised to hold public meetings and also have
the toll authority prove to the public that the project would be structurally and
financially sound. Men were trained to conduct travel surveys with “disarming
politeness” to evaluate support from the public for a 25-cent bridge toll. Due to
imminent PWA funding deadlines and the inconclusive opinion of the City of Seattle,
Congressman Warren G. Magnuson offered to make federal PWA funds available to
whatever bridge the City of Seattle selected as long as it selected quickly, in time
before the grants expired. 12 Mr. Murrow met with the mayor and a key council
member. By the margin of one vote, the nine-member City of Seattle Council elected
to endorse the floating bridge. The Lake Washington Protective Association
unsuccessfully attempted to have the Secretary of the Interior and PWA
Administrator Harold Ickes cancel the grant. Bridge construction began soon after
with groundbreaking of the $8.85 million project on December 29, 1938, just days
before the critical PWA grant expired.10
After the project was finished and its impacts and benefits could truly be seen, local
newspapers publicly reversed their opposition to the floating bridge by declaring the
bridge’s beauty to be “utterly amazing,” and a magazine hailed it as “the eighth
wonder of the structural world” when it opened in 1940.3,11 The opening day included
2,000 attendees for a grand opening celebration attended by the governor, mayors,
state officials, officials from area cities and counties, businessmen, politicians, and
dignitaries. 13
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
In Honor of a Great Engineer
Lacey V. Murrow, age 62, passed away in December, 1966. At the time of his death, he
was chairman of the board and recently retired president of Transportation Consultants,
Inc., Washington D. C.
He was a retired Brigadier General, United States Air Force, having served in every
theater of combat during World War II and the Korean War. His military honors included
the Legion of Merit and a presidential citation with four cluster decorations, as well as the
Croix de Guerre and the Order of the British Empire
His distinguished career as a professional engineer began with his appointment, at the
age of 28, as Director of the Washington State Department of Highways and concurrently
as Chief Engineer for the Washington State Toll Bridge Authority. He advanced the idea
for the first Lake Washington Floating Bridge, which was designed and constructed under
his direction.
Senate Resolution Number 1967-21, adopted by the Senate on February 25, 1967 and
passed by the House unanimously, stated that the Mercer Island Floating Bridge (the first
Lake Washington Bridge) “provide [sic] a unique, ingenious and resourceful solution to a
difficult engineering problem at the time it was designed and built, and more than twentyfive years later continues to serve the public well.” It requested that the State Highway
Commission designate the bridge as a tribute to Mr. Murrow.
The State Highway Commission concurred in Resolution Number 1815, adopted March
20, which stated that “this notable engineering achievement received worldwide
recognition for its pioneering of a new concept in over-water structures” and resolved that
the bridge be named “in honor of the engineer whose leadership turned this daring
proposal into a reality.”
Washington State Highway Commission: George D. Zahn. Chairman; James M. Blair Sr.;
Robert L. Mikalson; Harold Walsh; Baker Ferguson; Charles G. Prahl, Director of
Highways; Lorenz Goetz, Secretary
(Reprinted from the Washington State Highway Commission press release “In Honor of a Great Engineer” for
Lacey V. Murrow, Washington State Department of Transportation [WSDOT and State Department of Highways]
Records, Washington State Archives, Olympia, WA.)
Charles E. Andrew
Charles E. Andrew was the principal Construction Engineer in direct charge of the
project, as well as chief consulting engineer and Chairman of the Board of the
WTBA.
Born in Illinois in 1884, Charles Andrew graduated with a bachelor’s degree in civil
engineering from the University of Illinois in 1906. He immediately moved to Oregon
where he began his career building railroad bridges. In 1921, Mr. Andrew moved to
Washington and served for the next six years as the first bridge engineer for the
Washington State Highway Department. He left in 1927 for the San Francisco area,
where he remained for 10 years. In 1931, Mr. Andrew became the principal engineer
on the San Francisco-Oakland Bay Bridge, leading the design and construction of
the world’s largest bridge, completed in 1936.
When he returned to Washington in 1938, Mr. Andrew was a celebrity in bridge
engineering circles. He immediately set to work on the Tacoma Narrows Bridge
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
project as chief consulting engineer for the WTBA. He remained in this capacity for
two decades. During his tenure he guided construction of the 1940 and 1950
Tacoma Narrows Bridges, as well as the design and construction of the first two
floating bridges across Lake Washington and the floating bridge across Hood Canal.
Andrew passed away in 1969.
Considering the many unique features of floating bridges, the pioneering effort to
develop special design criteria was a remarkable achievement by Mr. Andrew. One
example was using moored barges and tugs to generate waves to determine wave
loading. Another was the analysis of temperature effects on a partially submerged
concrete structure. 14
Other Civil Engineers and Professionals
The WTBA project’s lead design team included several acclaimed engineers:
• Ray M. Murray, Bridge Engineer for the WTBA
• E. B. Wooliscroft, Designing Engineer
• D. I. McMurray, Tunnel Resident Engineer for the WTBA
• Clark Eldridge, Bridge Engineer for the WTBA
• Richard Barber, Resident Engineer for the west approach spans and floating
bridge
• Chomp E. Corser, Bridge Designer.
Other prominent engineers associated with the project, but not part of the WTBA,
included:
• L. R. Durkee, the Acting Project Engineer for the PWA
• Harold V. Judd, Engineer-Inspector, PWA
• Horace W. “Mac” McCurdy, who was with the Puget Sound Bridge and
Drydock Company, which cast the pontoon sections
• E. H. Thomas, Office Engineer, Lake Washington Floating Bridge
• Jacob Samuelson, Chief Engineer for construction and engineer for the
draw-span bridge.
• Lloyd Lovegren, East Portal architect
• James Fitzgerald, East Portal artist.
The contractors working on the project included:
• Pontoon Bridge Builders (a joint venture of Parker-Schram Company of
Portland, J.H. Pomeroy of San Francisco, Puget Sound Bridge & Dredging
Company of Seattle, and Clyde W. Wood of Los Angeles), constructed the
floating bridge
•
•
9
General Construction Company, Columbia Construction Company, and
Puget Construction Company, constructed the bridge approach structures
Bates and Rogers Construction Company, constructed the tunnels.
“’Hadley’s Folly’ Turned into Island’s Floating Bridge.” Mercer Island Reporter (January 2, 1991).
“Man Who Inspired Floating Bridge Gets His Due.” Journal American (July 13, 1993).
10
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
11
The information about Lacey Murrow in this paragraph and following (except where noted)
come from Dorpat, Paul and McCoy, Genevieve. Building Washington. Tartu Publications,
1998, pp. 120-123.
12
Holstein, Craig and Hobbs, Richard. Spanning Washington. Pullman: Washington State
University Press, 2005, p. 171.
13
Welch, Doug. “Huge Crowd Sees Floating Bridge Opened.” Seattle Post-Intelligencer (July 3,
1940).
14
Hobbs, Richard S. Catastrophe to Triumph, Bridges of the Tacoma Narrows. Pullman:
Washington State University Press, 2006, p. 119.
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
3. Historic international, national, or local significance of this landmark
Lacey V. Murrow Bridge
A concrete floating bridge of roughly 1.5-miles in length had not been designed or
constructed in the world before. The Washington State Department of Transportation
(WSDOT) and the Historic American Engineering Record (HAER) from the National
Park Service stated that the Lake Washington Bridge was the largest floating
structure ever built up to that time and the first reinforced-concrete floating bridge
ever built.2 The bridge incorporated the first floating concrete draw spans, which
were 378-feet long. This bridge’s successful construction paved the way for other
concrete floating bridges to be constructed.
The Murrow floating bridge enabled a 6.5-mile direct highway route from the town of
North Bend to downtown Seattle, saving drivers the 14 miles and 4,480 cumulative
degrees of road curvature by replacing the outdated and inadequate two-lane
highway. 15 The project led to the growth of communities on the east side of Lake
Washington, including Mercer Island, Bellevue, Redmond and Kirkland. See Figure
1 for a map showing the previous routes (a northbound route through Bothell and a
southbound route through Renton) and the current route (noted as “Proposed Route”
in the figure).
Mount Baker Tunnel
Construction of twin, 1466-foot-long, soft-bore tunnels through the Mount Baker
Ridge was needed to connect the City of Seattle with the proposed bridge route.
Mount Baker is a ridge of blue clay and, at the time, tunneling through such
formations was not common in the area. This project led to the construction of an
even larger-diameter tunnel used for the adjacent Homer H. Hadley Memorial Bridge
in 1989. With a diameter of 63 feet and a length of 1,476 feet, that newer stack drift
tunnel design superseded the original Mount Baker Ridge Tunnel as the world’s
largest diameter soft-earth tunnel. 16
National Concrete Floating Bridges that Followed
The Washington State Department of Transportation later constructed concrete
floating bridges in locations where conventional bridge building was impractical:15
•
•
•
The 7,866-foot Hood Canal Bridge, completed in 1961.
The 12,404-foot Governor Albert D. Rosellini Bridge-Evergreen Point Bridge,
completed in 1963.
The 9,559-foot Homer M. Hadley Memorial Bridge, which crosses over Lake
Washington parallel to the original bridge, and was completed in 1989.
WSDOT took over the role of the earlier WTBA, which built the first bridge. A
significant amount of repair work and improvement became necessary over the
years, and WSDOT became fully familiar with the design requirements for this type
of structure. When a new floating bridge was needed for the I-90 corridor, WSDOT
was capable of doing the design, with assistance by private firms for dynamic
response analysis.
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
The Hood Canal Bridge was built across an inland sea and was designed to
withstand salt water and tide changes of 18 feet in water that is deeper than that of
Lake Washington. Following the storm damage of the Hood Canal Bridge in 1979,
investigations were made by WSDOT and private engineering firms retained by the
WSDOT. The damage investigation focused on a dynamic response analysis, using
analytical models developed by the offshore oil industry during the 1970s. Modern
floating bridge design employs techniques from a number of other disciplines,
including wind and wave analysis, structure dynamics, naval architecture, and
marine construction. The second Hood Canal Bridge was rebuilt and opened to
traffic in October of 1982.
The Evergreen Point Bridge is located four miles north of the Lacey V. Murrow
Bridge. It was built to carry additional traffic demand across Lake Washington. The
bridge incorporated partial prestressing in addition to mild steel reinforcement. This
bridge span is greater than the Lacey V. Murrow Bridge and is therefore more
susceptible to effects from wave action.
Two other concrete floating bridges are known to have been constructed in the
United States, outside of Washington State. In 1945, a 170-foot long four-lane
retractable concrete pontoon bridge was constructed in Los Angeles Harbor to
cross the east entrance of the Cerritos Channel (at the current southwest terminus of
Interstate 710). The bridge was constructed for “a wartime need”, and was replaced
by the Gerald Desmond Bridge in 1968. The pontoon bridge was built under the
direction of Vice Admiral B. Moreell, CEC, of the United States Navy. Consulting
engineers included Austin W. Earl of San Francisco, California and Charles E.
Andrew of Tacoma, Washington. 17 Also, the 5,610-foot Admiral Clarey Bridge was
completed in 1999 in Pearl Harbor, Hawaii and includes a 930-foot retractable
concrete pontoon draw span.
International Concrete Floating Bridges that Followed
As the Chief Engineer for the Toll Bridge Authority, Charles Andrew was the leading
designer of the first three floating bridges in Washington State. He became the
authority on floating bridge engineering and served as a consultant to other entities
interested in this type of bridge. The Canadian engineering company, Swan
Wooster, used the WTBA’s Charles Andrew as a consultant during their design of
the Kelowna Floating Bridge on Lake Okanagan in British Columbia. 18
As the years went by, interest in floating bridges was shown by foreign countries,
and the expertise of the WSDOT staff was often sought through correspondence and
visitations. Charles Gloyd, WDOT Chief Bridge Engineer 1972-1989 recalls inquires
from Japan, Norway, Greece, and Turkey. 19 Japanese engineers actually donated
time during construction of the Washington State SR-520 Bridge (Evergreen Point
Bridge) in order to understand how to build floating bridges in Japan. This activity
eventually led to the Japan Society of Civil Engineers Guidelines for Design of
Floating Bridges. 20
Norwegian engineers visited the Washington State floating bridges and interviewed
design and maintenance engineers. They subsequently sponsored the travel of two
WSDOT engineers, Robert Krier and Myint Lwin, to Norway to consult during the
planning stages of two floating bridges later built in that country.
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
A number of concrete floating bridges were built outside the United States after the
Lacey V. Murrow Memorial Bridge (see Figures 7 through 9 in Section 8): 21
•
•
•
•
•
•
In 1943, the 3,164-foot Hobart Bridge in Tasmania, Australia, was completed
with hollow concrete pontoons crossing the Derwent River. This bridge has since
been replaced. 22
The 2,100-foot Kelowna Floating Bridge also known as the Okanagan Lake
Bridge, was completed in 1958 in Kelowna, British Columbia, Canada.
The Takahiko-Three County Golf Course Prestressed Concrete Floating
Bridge was built in 1992 in Daigo Town, in the Ibaraki Prefecture in Japan. This
185-foot long bridge is constructed of concrete and prestressed fiber reinforced
plastics and is used for golf cart and maintenance vehicle traffic. 23
The 3061-foot Bergsoysund Bridge floating section spans more than 2,600-feet
across. It was completed in 1992 and is located in Kristiansund, Norway.
The 4,088-foot Nordhordland Bridge or Salhus Bridge was completed in 1994
in Bergen, Norway, with a 3,800-feet floating bridge portion to cross the Salhus
Fjord.
The 2,880-foot Yemenai Bridge includes a 1,200-feet swinging float bridge
section and was completed in 2000 in Osaka, Japan.
15
Murrow, Lacey V., “A Concrete Pontoon Bridge To Solve Washington Highway Location
Problem.” Western Construction News (July 1938): p. 249.
16
Mount Baker Ridge Tunnel, Historic American Engineering Record No. WA-109, p. 8.
17
“Four-Lane Retracting Pontoon Bridge.” Engineering News Record 839 (June 14, 1945): pp.
102-104.
18
Personal interview with Charles S. Gloyd, WSDOT Olympia, WA (April 7, 2007).
19
Personal interview with Charles S. Gloyd, WSDOT Olympia, WA (April 7, 2007).
20
Personal interview with Patrick Clark, Floating Bridge & Special Structures Design Manager,
WSDOT Olympia, WA (November 17, 2006).
21
”Hood Canal Bridge Retrofit and East Half Replacement Project.” WSDOT Communications
Office (May, 2005). http://www.wsdot.wa.gov/NR/rdonlyres/E9F9AD95-7974-4A89-855EDE815003E051/0/HCBMay2005.pdf )
22
Sharland, Michael. “Hobart Pontoon Bridge.” Indian Engineering 120 (February, 1947): pp. 7778.
23
Tezuka, Masamichi; Morisita, Shogo; Kai, Kazuo; Kokota, Tsutomu; and Niwano, Takashi.
“Design and Construction of Precast Prestressed Concrete Floating Bridge Reinforced by only
FRP.” FIP Symposium 1993, Kyoto, Japan (October 17-20, 1993). Prestressed Concrete
Engineering Association, Tokyo, Japan: pp. 655-662.
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
4. Comparable or similar projects in the United States and other countries
Pontoon bridges have existed since early civilization. They were used by the Persian
armies that crossed the Hellespont to invade Greece in 480 BC. In his 1921 paper to the
Seattle section of ASCE, Homer Hadley described non-experimental pontoon bridges of
wood and steel used prior to that date. 24 These include the following:
•
•
•
•
•
•
•
The Chicago, Milwaukee, and St. Paul Railroad had two pontoon railroad spans
across the Mississippi River at Prairie du Chien, Wisconsin.
A 303-foot railroad pontoon scow was used at Lake Champlain, N.Y., from 1851
to 1868.
A 1000-foot pontoon bridge had been maintained since 1819 that crossed the
Rhine at Koblenz, Germany.
A 300-foot highway and railroad pontoon bridge crossed the Panama Canal at
Paraiso.
A 1770-foot highway bridge crossed the Dvina River at Riga, Russia.
A 1530-foot bridge was built across the Golden Horn at Constantinople in 19111912.
In 1874, a pontoon bridge was built to cross the Hoogli River at Calcutta, India.
Several floating bridges were constructed of steel or wood around the time of the Lacey
V. Murrow Bridge. Examples include the steel pontoon bridge built in 1912 in Istanbul.
The bridge was built with fifty steel pontoons connected by hinges. 25 Other pontoon
bridges include swing spans constructed in Curacao in 1923 and in Chicago in 1924.20
An early floating concrete bridge was built in 1943 across the Derwent River in Hobart,
Tasmania, Australia. Mr. A. W. Knight developed the idea of building a roadway on
floating pontoons and patented the idea in Canberra on February 26, 1936. The bridge
featured floating airtight concrete chambers that were rigidly welded together in the form
of a crescent to withstand the river current. It was built without anchors but hinged to
abutments. The bridge had one expanding joint in the center. A lift span, which was
separate from the floating portion of the bridge, was included on the Hobart side of the
river. It had a 145-feet boat clearance.16 The Tasman Bridge replaced the floating
bridge in 1964.
24
Report on Proposed Bridge Across Lake Washington at Seattle, WA to ASCE by Homer M.
Hadley (October 1, 1921), Washington State Department of Transportation, pp. 4-5.
25
Watanabe, Eiichi, “Floating Bridges: Past and Present.” Structural Engineering International 13
(February, 2003): p. 128.
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
5. Unique features or characteristics which set this proposed landmark
apart from other civil engineering projects
There are only a few features of the Lake Washington Floating Bridge that are not
unique when compared to ordinary bridges. The roadway deck slab, sidewalks and
railings were similar to other bridges, but the other bridge features were dictated by the
floatation requirements. Compared to other floating bridges, the use of concrete and the
continuous rigid structure concept are the most significant of the following unique
features.
Structure type
It was the first bridge to utilize concrete pontoons as the primary structural element.
The pontoons were typically 300-feet long and were cellular in configuration,
providing the necessary buoyancy, and were joined rigidly end to end to form a
continuous structure. All previous floating bridges utilized discrete pontoons joined
by hinged connections or simple span roadway beam elements; these were most
often temporary military applications made of wood or steel. The depth of the Lake
Washington bridge cellular pontoons was varied to provide the proper buoyancy to
support the dead load of the structure immediately above it, thus minimizing bending
and shear stresses. The concrete mix and construction technique were carried out
in a manner to control shrinkage cracking and create a nearly watertight structure, a
feature not critical in ordinary concrete bridges. Pontoon cells were formed by a
series of interior walls and bulkheads, with openings in some to enable maintenance
access to all cells. Each group of cells was isolated by a solid transverse bulkhead
so that any flooding would be confined to a small portion of the structure. Access for
inspection and maintenance was provided through hatches in the sidewalk.
Restraint system
Anchor cables were used both transversely and longitudinally to moor the floating
structure in place, a feature not needed for fixed bridges. Anchors placed in the lake
bottom were connected by steel cables to the pontoons with adjustable tensioning to
accommodate variations in lake water level. The cable anchorage system acted like
a series of springs to provide the stability needed to avoid excessive ship-like
motions. To determine the forces on the cables due to wave action, Charles Andrew
devised experiments conducted on Lake Washington during the design of the bridge.
He used barges to simulate the bridge and tug boats to generate waves. Anchors
were of three types, depending on lake bottom conditions. Most were large,
concrete, fluke-type anchors, similar in shape to a ship’s anchor, jetted into place in
the soft lake bottom area. Where the bottom was firm, the anchors were large
concrete boxes filled with ballast. In the shallow water close to the shore, a cluster of
driven steel piles was used.
Accommodation of movement
Rather than using a rigid link at the approach transition spans at either end of the
floating bridge, a longitudinal and transverse cable anchorage system was employed
to hold the structure in position and accommodate the four-foot seasonal variation in
water elevation. Due to wind and wave action, the floating bridge could move
similarly to a moored ship; laterally, longitudinally, and could also roll about its
longitudinal axis. The cable system needed to provide stability and restrain the
motion such that bearings and roadway expansion joint mechanical devices of a
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
practical size could accommodate the motions at the transition spans. These
devices had to accommodate angular displacements as well as changes in the
horizontal position of the bridge.
Floating Draw Span
This unit of the bridge had to be of sufficient length so that by moving back and forth
between flanking pontoons it could provide the required navigation opening of 200feet. It also needed to be restrained by these adjacent flanking pontoons only,
without any anchor cables of its own. The design used horizontal and vertical rollers
mounted on the flanking pontoons to control the alignment of the draw pontoon as it
was moved back and forth by means of a drive system. The drive system was a
cable and sheave design powered by direct current electric motors; it could open or
close the navigation span in a few minutes. Mechanical locking devices connected
the drawspan to the flanking pontoons and to the mating pontoons non-moveable
pontoon unit. The drawspan unit was removed in the early 1980s and replaced by a
fixed pontoon identical to the others. The unit was removed to improve traffic safety
by eliminating the curved roadway and the flanking pontoons, and it was feasible
because navigation requirements on the lake had changed so that the channel east
of Mercer Island was sufficient.
Construction method
The concrete pontoons were built in the dry in a graving yard created just for this
project and located several miles away on the Duwamish River waterway in Seattle.
After pontoon hulls were constructed, the graving yard was flooded to float the
pontoons. They were then completed at an outfitting dock, and towed through Puget
Sound and the Ballard Locks into Lake Washington. The width and length of the lock
chambers limited the size of the pontoons. The pontoons were connected by means
of bolted joints between the end bulkheads. A cofferdam was installed around each
joint during bolting so that the space between end bulkhead surfaces could be filled
with concrete grout to complete the connection. This was an early form of segmental
concrete bridge construction.
Tunnel Construction
The project included the design and construction of twin 1466-foot soft-bore tunnels
through the 260-foot high Mount Baker Ridge to connect the City of Seattle with the
lake bridge. The HAER report about the tunnel states that these were the world’s
largest-diameter, soft-earth tunnels at the time.19 The 1,466-foot tunnels each
accommodate two 12-foot wide lanes and a 3-foot wide sidewalk. Each arch reaches
23 feet above the roadway and is 28 feet and 11 inches wide. The tunnels had to be
constructed by excavating seven plump-drifts through heavy blue clay using electric
pneumatic shovels and air spades. 26 The drifts were braced with heavy timbers
every 3 feet in order to excavate the soil in between, as shown in Figure 3. The
material required no drilling or explosives. The 125-foot maximum cover exerted
tremendous forces on the shoring until the 24-inch concrete lining was placed. 27
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
Western Construction News, July 1940.
Figure 3: Construction of the Mount Baker Tunnels
26
Dorpat, Paul and McCoy, Genevieve. Building Washington. Tartu Publications, 1998, pp. 120123.
27
“Twin Tunnels Driven Through Clay for Lake Washington Bridge Project.” Western
Construction News 15 (July, 1940): pp. 246-249.
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
6. Contribution which this structure or project made toward the
development of the civil engineering profession and the nation or a
large region thereof
This project is an outstanding technical engineering achievement. It marks a significant
success in the collaboration between a state highway agency, the federal government,
local agencies, and the public, who worked together to expedite and create one of the
more innovative civil works projects in history, and one of great benefit to the Northwest
region.
The Lacey V. Murrow Memorial Bridge proved that a concrete floating bridge could be a
cost-effective and practical solution for situations in which conventional bridge piers
would have to be made unreasonably deep. It paved the way for future construction of
other floating bridges throughout the world.
This project pioneered the first design of a floating concrete pontoon draw span.
Floating concrete sliding draw span bridge sections have been subsequently built
throughout the country. Floating concrete draw spans were built at the east end of
Cerritos Channel in Los Angeles Harbor, California; as part of the Admiral Clarey Bridge
in Pearl Harbor, Hawaii; and with the Hood Canal Floating Bridge and Evergreen Point
Floating Bridge in Washington.
The project’s successful construction of twin, large-diameter, 1466-foot, soft-bore
tunnels through Mount Baker led to the creation of the even larger-diameter Mount
Baker Ridge Tunnel, used for the Homer H. Hadley Memorial Bridge completed in 1989.
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
7. Published references concerning this nomination
Reference material enclosed in the appendix of this application:
A. A copy of the original engineering plan and profile of the bridge. STET 1180F Lake
Washington Bridge Unit No. 4, Sheet 1 and Unit No. 3, Sheet 1. Washington State
Department of Transportation (WSDOT and State Department of Highways)
Records, Washington State Archives, Olympia, Washington. Engineer Records,
Plans Vault, Olympia.
B. A copy of the original engineering plan and profile of the Mount Baker Ridge Tunnel.
STET 1180F Lake Washington Bridge Unit No. 2, Sheet 2. Washington State
Department of Transportation (WSDOT and State Department of Highways)
Records, Washington State Archives, Olympia, Washington. Engineer Records,
Plans Vault, Olympia.
C. “WSDOT’s 50th Anniversary of Lacey V. Murrow Floating Bridge.” WSDOT press
release, 1990, Washington State Department of Transportation (WSDOT and State
Department of Highways) Records, Washington State Archives, Olympia, WA.
D. Andrew, Charles. “Eighth Wonder of the Highway World…The Lake Washington
Floating Bridge.” Pacific Builder and Engineer 46 (July 6, 1940): pp. 29-33.
E. Report on Proposed Bridge Across Lake Washington at Seattle, WA. to ASCE by
Homer M. Hadley (October 1,1921), Washington State Department of Transportation
(WSDOT and State Department of Highways) Records, Washington State Archives,
Olympia, WA.
F. Wooliscroft, B. “World’s First Draw Pontoon.” Pacific Builder and Engineer 46
(August 3, 1940): p. 46.
G. Corser, Champ E. “The Transition Section.” Pacific Builder and Engineer 46 (August
3, 1940): p. 44.
H. Hagglund, Daniel E. “Lacey V. Murrow Memorial Bridge” (Lake Washington Floating
Bridge) (Mercer Island Floating Bridge).” Historic American Engineering Record No.
2, 1989.
I. Clark, Jonathan. “Mount Baker Ridge Tunnel.” Historic American Engineering Record
No. 109, 1993.
J. “Twin Tunnels Driven Through Clay For Lake Washington Bridge Project.” Western
Construction News 15 (July, 1940): p. 246.
Other reference material not included in the appendix:
Dorpat, Paul and McCoy, Genevieve. Building Washington. Tartu Publications, 1998.
Engstrom, John. “Our Hearts Sank.” Seattle Post-Intelligencer. December 20, 1990.
Hobbs, Richard S. Catastrophe to Triumph, Bridges of the Tacoma Narrows.
Pullman: Washington State University Press, 2006.
Holstein, Craig and Hobbs, Richard. Spanning Washington. Pullman: Washington
State University Press, 2005.
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
Japan Society of Civil Engineers. Steel Structures Series 13: Guidelines for Design
of Floating Bridges. Japan Society of Civil Engineers press. March, 2006.
McDonald, Lucile. “The Inspiration for the First Floating Bridge.” Seattle Times. July
26, 1964.
Murrow, Lacey V., “A Concrete Pontoon Bridge to Solve Washington Highway
Location Problem.” Western Construction News. July 1938.
Sharland, Michael. “Hobart Pontoon Bridge.” Indian Engineering 120. February,
1947: pp. 77-78.
Tezuka, Masamichi; Morisita, Shogo; Kai, Kazuo; Kokota, Tsutomu; and Niwano,
Takashi. “Design and Construction of Precast Prestressed Concrete Floating Bridge
Reinforced by only FRP.” FIP Symposium 1993, Kyoto, Japan (October 17-20,
1993). Prestressed Concrete Engineering Association, Tokyo, Japan: pp. 655-662.
Washington State Department of Transportation. “I-90 Bridge Bulge to be Replaced
Over Labor Day Weekend (Sept. 4-8).” WSDOT press release, Washington State
Department of Transportation (WSDOT and State Department of Highways)
Records, Washington State Archives, Olympia, WA. August 17, 1981.
Washington State Department of Transportation. “New Lacey V. Murrow Bridge
Named Outstanding Engineering Achievement.” WSDOT press release, Washington
State Department of Transportation (WSDOT and State Department of Highways)
Records, Washington State Archives, Olympia, WA. January 12, 1994.
Watanabe, Eiichi. “Floating Bridges: Past and Present.” Structural Engineering
International 13. February, 2003: p. 128.
Welch, Doug. “Huge Crowd Sees Floating Bridge Opened.” Seattle PostIntelligencer. July 3, 1940.
“’Hadley’s Folly’ Turned into Island’s Floating Bridge.” Mercer Island Reporter.
January 2, 1991.
“Man Who Inspired Floating Bridge Gets His Due.” Journal American. July 13, 1993.
“Four-Lane Retracting Pontoon Bridge.” Engineering News Record. No. 839. June
14, 1945: pp. 102-104.
”Hood Canal Bridge Retrofit and East Half Replacement Project.” WSDOT
Communications Office (May, 2005).
http://www.wsdot.wa.gov/NR/rdonlyres/E9F9AD95-7974-4A89-855EDE815003E051/0/HCBMay2005.pdf )
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
8. A list of additional documentation in support of this nomination.
Lacey V. Murrow Bridge, 1941. WSDOT Photo Collection, Washington State Archives.
Lacey V. Murrow Bridge, Dec. 12, 1974. WSDOT Photo
Collection, Washington State Archives.
I-90 Tunnel to Lacey V. Murrow Bridge. WSDOT Photo
Collection, Washington State Archives.
Lacey V. Murrow Bridge, 1940, by Alfred G. Simmer. WSDOT Photo Collection, Washington State Archives.
Figure 4 – Photographs of Tunnel Portals and West Bridge Approach
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
Lacey V. Murrow Bridge
Construction, 1940, by Alfred G.
Simmer. WSDOT Photo Collection,
Washington State Archives.
Lake Washington Bridge, Feb. 28, 1979. WSDOT Photo Collection,
Washington State Archives.
Figure 5 – Photographs of Bridge Draw Span
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
“Shovel Crew” at start of Tunnel Excavation at East Portal, Lacey V. Murrow Bridge, 1939.
WSDOT Photo Collection, Washington State Archives.
Lake Washington Floating Bridge Cross Section of Pontoon Structure, by
Lloyd Lovegren. WSDOT Photo Collection, Washington State Archives.
Figure 6 – Photographs of Engineering Staff and Bridge Pontoon Sections
Page 23
Translated from Guidelines for Design of Floating Bridges, Japan Society of Civil Engineers, March 2006, p. 8.
Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
Figure 7 – Major Floating Bridges around the World (see Figure 8 for locations)
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
Translated from Guidelines for Design of Floating Bridges, Japan Society of Civil Engineers, March 2006,
p. 8.
Figure 7 (continued) – Major Floating Bridges around the World (see Figure 8)
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
Figure 1.1.6 from Guidelines for Design of FloatingBridges, Japan Society of Civil Engineers, March 2006,
p. 9.
Figure 8 – Map of Major Floating Bridges around the World
Page 26
Translated from Guidelines for Design of Floating Bridges, Japan Society of Civil Engineers, March 2006, p. 14.
Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
Figure 9 – Reasons for Using Floating Bridges at Various Locations
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
9. The recommended citation for History and Heritage Committee
consideration.
The Lacey V. Murrow Bridge was the largest and longest floating bridge at the time of its
construction and the first built of concrete. The project includes two tunnels which were
the largest diameter soft-earth tunnels at the time. The bridge was conceived by civil
engineer Homer Hadley, and built under the direction of Lacey V. Murrow, Chief
Engineer of the Washington Toll Bridge Authority. The floating structure was constructed
by Pontoon Bridge Builders and the tunnels by Bates and Rogers Construction
Company. Similar projects in the United States, Canada, Norway, and Japan followed
this design.
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels
10. A statement of the owner’s support of the nomination.
See the introduction of this nomination for a copy of the Washington State Department of
Transportation’s letter supporting the nomination.
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Lacey V. Murrow Memorial Bridge and Mount Baker Ridge Tunnels