Lacey V. Murrow Memorial Bridge sinks to the bottom of Lake Washington

Lacey V. Murrow Memorial Bridge sinks to the bottom of Lake Washington


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After a howling wind- and rainstorm on Thanksgiving Day, Washington state’s historic floating Lacey V. Murrow Memorial Bridge breaks apart and sinks to the bottom of Lake Washington, between Seattle and its suburbs to the east. Because the bridge’s disintegration happened relatively slowly, news crews were able to capture the whole thing on camera, broadcasting it to a rapt audience across western Washington. “It looked like a big old battleship that had been hit by enemy fire and was sinking into the briny deep,” said one observer. (He added: “It was awesome.”)

The Murrow Bridge was the brainchild of engineer Homer Hadley, who in 1921 proposed a “floating concrete highway, permanent and indestructible, across Lake Washington.” Figuring out a way to cross that lake, between up-and-coming Seattle and its (at that time) sleepy small-town neighbors to the east, was a particular challenge because an ordinary “fixed-pier” bridge was out of the question: The lake was too deep, and its bottom was too mushy. Still, people scoffed at what they called “Hadley’s Folly” (one civic organization declared that his “chain of scows across Lake Washington would stand out as a municipal eyesore”), but eventually, mostly because they had no other options, they came around to his way of thinking. Construction began on the bridge, named after the state highways director (and brother of famous newsman Edward R. Murrow), in 1939; it was completed 18 months later.

In November 1990, the 6,600-foot-long bridge, made of 22 floating bolted-together pontoons, was in the process of being converted from a two-way road to a one-way road. (A parallel bridge had been completed the year before, effectively doubling the amount of traffic that could cross the lake.) The state highway department alleged that construction crews had left the pontoons’ hatches open, leaving them vulnerable to the weekend’s heavy rains and large waves. (For its part, the construction company refused to accept responsibility for the disaster, countering that “the probable cause of the failure was progressive bond slip at lapped splices in the bottom slab…due to failure in bond.” It did eventually agree to pay the state $20 million, however.) For whatever reason, at midday on November 25, the center pontoons began to sink. As they disappeared under the water, they pulled more and more of the crumbling roadway down with them. By the end of the day, the bridge was gone.

Fortunately, no one was injured in the incident. The Murrow Bridge was soon rebuilt.


Pamätný most Laceyho V. Murrowa klesá na dno jazera Washington

Po vytie vetra a dažďovej búrke v Deň vďakyvzdania a hitorický plávajúci štátny pamätný mot Lacey V. Murrow Memorial štátu Wahington rozpadne a kleá na dno


2nd Gear: Autonomous Vehicles And Regulation

Under the Trump administration, the federal government has largely declined to set rules around autonomous cars, preferring to let individual states decide. This is in keeping with the Trump administration’s timidity when it comes to making bold moves in general, though a new report from the World Economic Forum outlines why regulation is sorely needed.

Countries that set a strong national policy can gain certain fast-mover advantages. Tim Dawkins, lead author of the report, says that autonomous-vehicle operations are ultimately conducted at the local level. Policies that might work in Phoenix might not work in Pittsburgh.

“Safety needs to be defined by the operating environment,” he said. “That unfortunately is not going to allow interoperable licensing or permitting approaches. It’s just the reality of development. But if we agree on common terms and at a baseline level that a learner’s permit is a first step, that’s where we see this framework fitting.”

Chief among the WEF’s recommendations: Develop scenario-based assessments that represent the challenges AVs will face in their given environments. These assessments can occur through a combination of simulation, closed-course testing and real-world road tests and be based on a scenario library that can be subsequently be used by regulators to set safety benchmarks.

“No two companies should have to experience the same near-miss twice, and this becomes a shared resource, and breaks down tendencies to compete on the basis of safety,” says Michelle Avary, head of automotive and autonomous mobility at the WEF.

Making autonomous cars use open-source software actually makes a lot of sense when you think about it, but I doubt Tesla and Cruise and Zoox and Uber will be rushing to do that anytime soon without some prodding.


Lacey V. Murrow Memorial Bridge sinks to the bottom of Lake Washington - HISTORY

This Day In History: November 25, 1990

On November 25, 1990, the Lacey V. Murrow Memorial Bridge broke into pieces and sank to the bottom of Lake Washington. After a week-long windswept rainstorm, the old bridge succumbed to the forces of nature and gradually disappeared beneath relentless waves. Since the bridge’s demise was a gradual process, the local media could gather at the scene, allowing everyone enjoying their Thanksgiving holiday weekend to follow along at home. One witness said, “It looked like a big old battleship that had been hit by enemy fire and was sinking into the briny deep.” He added, “It was awesome!” Luckily, no-one was hurt.

When the bridge opened for business on July 2, 1940, Washington Governor Clarence Martin described it as “original, distinctive, striking and graceful — a product of this great state’s vision and constructive spirit.” The floating bridge, originally called the Lake Washington Floating Bridge or the Mercer Island Bridge, was considered a marvel of engineering. It was also the “biggest thing afloat”, easily dwarfing the ocean liner the Queen Elizabeth its closest competition.

By November 1990, the Lacey V. Murrow Memorial Bridge (renamed in 1967 after Washington’s highway director) was in need of repairs after 50 years of service. (A twin span had been built parallel to it to accommodate the thousands of commuters who used it daily.) During construction, workers had cut holes into the hollow concrete pontoons on the old bridge and failed to close them up before the long holiday weekend. When a heavy storm hit, the pontoons filled up with water and submerged under the surface.

This, of course, was not a happy situation, and last-ditch efforts were made to pump out the pontoons, but it was much too late. By that point, news helicopters were circling overhead as the bridge began to creak and sag. As the morning turned to afternoon, portions of the bridge broke off and disappeared under the water. Finally, the last pieces upended, tilted, and then slid to the bottom of Lake Washington. If you listened closely, Celine Dion was warbling a dramatic ballad somewhere off in the distance.

Predictably, there was arguing between the State Highway Department and the construction company over who was at fault. In the end, the construction company had to pay out $20 million, so you can draw your own conclusions.

If you liked this article, you might also enjoy our new popular podcast, The BrainFood Show (iTunes, Spotify, Google Play Music, Feed), as well as:


Lacey V. Murrow Memorial Bridge sinks to the bottom of Lake Washington - HISTORY

Building History

This floating bridge, the longest in the world when built, accommodated two lanes of traffic going east and west. Engineer Henry More Hadley (1885-1967), who worked with the Seattle School District and later the Portland Cement Company, devised the bridge's radical floating concrete pontoon design, first proposing the idea at a American Society of Civil Engineers (ASCE) conference in 1921. His design was necessitated by Lake Washington's unusual depth, between 150 and 200 feet deep under the bridge's path. Over millions of years, seven periods of glaciation have influenced the topography of Puget Sound, the last being the Vashon Stade, at its largest extent 13,000 years ago. Glacial scouring and the effects of subglacial meltwater flows carved away deep troughs throughout Puget Sound region, depressions that were ultimately filled in by seawater and later freshwater one of these topographic gouges became Lake Washington. Due to lake's great depth and soft bottom conditions, sinking pilings for a conventional bridge would become impractical and costly. By 1937, the Roosevelt Administration and Congress released federal funds for large public works. With this incentive of federal assistance, Hadley's unorthodox idea began to appeal to state highway administrators, including Lacey V. Murrow (1904-1966), the second Director of the Washington State Highway Department (1933-1940) and the Chief Engineer of the Washington Toll Bridge Authority (1937-1940). With his backing in 1937-1938, Hadley's floating span concept was accepted and completed in 1939-1940. (Soon after the bridge's completion in 09/1940, Lacey Murrow resigned his State of WA positions to become a decorated pilot for the US Army Air Corps and never again resided in WA.) A mix of federal money and tolls paid the 3,000 people who worked on the bridge. Tolls collected from 1940-1946 defrayed the bridge's $5.5 million cost approximately a million cars traveling over the bridge per year were needed to pay off the debt. The State of WA renamed the bridge in Lacey Murrow's honor in 1967, two years after his death from lung cancer. (Tragically, lung cancer also ended the life of Lacey's brother, famed CBS News commentator, Edward R. Murrow [1908-1965].) The Murrow Bridge was rebuilt in the years after its sinking in 1990 to carry eastbound traffic on U.S. Interstate 90 westbound traffic during peak hours was carried on the parallel Homer M. Hadley Bridge (completed in 1989) located to the north of the Murrow span.

Building Notes

The Lake Washington Floating Bridge, spanned one-and-a-half miles and floated on water often 200 feet deep construction began 12/29/1939 and finished 07/02/1940 at the time of its completion, it was the longest floating bridge in the world and weighed 100,000 tons Governor Clarence D. Martin (1886-1955) presided at its opening ceremony to which 11 Western U.S. governors, the Premier of British Columbia and the Governor of the Territory of Alaska were invited. According to the Seattle Times of 06/16/1940: "The ceremonies are part of a 'one-two-three' dedication in the first week of July, celebrating completion of $22,500,000 in public projects in the Puget Sound area. July 1 the Narrows Bridge will be opened at Tacoma, linking the west and east side of Puget Sound, July 2 and 3 will honor the Lake Washington project, and July 3 also will mark the official opening of the $7,000,000 McChord Field, huge Army base north of Fort Lewis." (See "Pioneer Will 'Launch' Pontoon Bridge July 2 Details of Big Civic Celebration Announced," Seattle Times 06/16/1940, p. 9.) Paul Dorpat noted of the opening ceremonies: "About 2,000 people watched from the tunnel plaza area here on the bridge's Seattle side, and hundreds more gathered around toll booths at the bridge's Mercer Island end to attend the christening, which was broadcast by radio nationwide. Kate Stevens Bates, daughter of Washington Territory's first governor, Isaac Stevens, let swing and crash against the concrete bridge a yellow urn in which were mixed the waters of 58 of the state's waterways: lakes, bays and rivers." (See "Paul Dorpat, "A Bridge to Progress," Seattle Times Pacific Northwest, 03/27/2011, p. 18.) On 06/11/1979, the Murrow Bridge was named a City of Seattle Landmark.

Demolished 850 meters (approximately 2789 feet) of this floating span sank to the bottom of Lake Washington during a storm in 11/25/1990. It sank after State of Washington Department of Engineers had started work to widen the bridge. In order to do this, sidewalks were blasted away with water sprayed at high pressure this water, because it was considered polluted, was not allowed to flow into Lake Washington, and had to be stored somewhere. Engineers decided to store it in the pontoons supporting the bridge. Workers for the Traylor Brothers Construction Company broke six-foot holes in some pontoons into which they intended to pump waste water, but fierce storms on 11/22-24/1990 filled them with rainwater and lake water as well. Overloaded, one pontoon sank causing all of the other pontoons chained to it to drag the bridge to the bottom.


5th Gear: Another UAW Official Resigns

Vance Pearson was director of UAW Region 5, but last week the union moved to expel him and UAW President Gary Jones. Jones resigned almost immediately , while Pearson resigned over the weekend. Both Pearson and Jones have been linked to an ongoing corruption scandal within the union.

“The UAW announced today that after the filing of Article 30 charges against him by the UAW’s International Executive Board, Vance Pearson has informed the UAW that he was resigning as director of UAW Region 5, effective immediately, and retiring. He is also resigning his UAW membership, effective immediately. Mr. Pearson had been on leave from his position.”

Pearson’s attorney, Scott Rosenblum of St. Louis, said that rather than pursuing an Article 30 hearing, Pearson would be focusing on his defense in the criminal case, which Rosenblum declined to discuss.

[. ]

Pearson, 58, of St. Charles, Missouri, also faces six federal criminal charges that accuse him of embezzlement of union money, mail and wire fraud, money laundering and conspiracy.


Lacey V. Murrow Bridge Disaster

The Lacey V. Murrow Memorial Bridge is 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 Homer M. Hadley Memorial Bridge running parallel to it. The Lacey V. Murrow Memorial Bridge is the second-longest floating bridge on Earth at 6,620 ft (2,020 m), whereas the longest is the Governor Albert D. Rosellini Bridge—Evergreen Point just a few miles to the north on the same lake, opened 76 years later. The third-longest is the Hood Canal Bridge, also in Washington State, about 30 miles (48 km) to the northwest of the Evergreen Point Floating Bridge.

In 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. 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, 1990 (the Thanksgiving holiday weekend) filled some of the pontoons with rain and lake water. On November 24, workers noticed that the bridge was about to sink, and started pumping out some of the pontoons. However, on November 25, 2,790 ft (850 m) of the bridge sank, dumping the contaminated water into the lake along with tons of bridge material. The bridge 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. All of the sinking was captured on film and shown on live TV. The cost of the disaster was $69 million in damages.

The disaster delayed the bridge's reopening by 14 months, to September 1993 . More details


That Time A Bridge Sank Due To A Sublime Roadworks Fail

We drive across all kinds of bridges every day. Whether it be an ordinary bridge over a small creek, a grandiose suspension bridge like the Golden Gate Bridge in San Francisco, or the 24-mile-long Lake Ponchartrain Causeway, most bridges have one thing in common: they’re usually supported, in part, by a series of pilings driven into the bottom of whatever body of water they cross.

However, one bridge across in Seattle is quite a bit different. The Lacey V. Murrow Memorial Bridge, which carries Interstate 90 across Lake Washington, doesn’t have any pilings tethering it to the ground. This is because, at its deepest point, Lake Washington is well over 200 feet deep. It’s not exactly practical to fabricate 200-foot-long concrete pilings and then transport them to the construction site. Luckily, the conditions of Lake Washington allowed for a simple, yet ingenious solution. The answer was to build a bridge that floated over the lake.

The concept of a floating bridge is fairly simple: instead of using pilings, the bridge relies on a series of concrete pontoons to support the bridge deck. In essence, the bridge behaves like a giant boat, relying on a series of cables anchored to the bottom of the lake to keep it in place. The design is ideal for Lake Washington because there are no strong currents or high waves, and the lake itself is very deep. Not surprisingly, when engineers in Washington state wanted to connect the city of Seattle to Mercer Island, the natural decision was made to build a pontoon bridge to do the job. In 1940, the Lacey V. Murrow Memorial Bridge opened to the public.

Named after the former director of the Washington State Highway Department, the Murrow bridge became a critical component of the interstate highway network. For 50 years, the bridge saw an inordinate amount of vehicle traffic, eventually necessitating the construction of an adjacent bridge to alleviate the traffic problems. In 1990, the bridge was set to undergo routine maintenance when a series of basic engineering mistakes resulted in a somewhat embarrassing disaster.

The plan to rehabilitate the bridge consisted of widening, then resurfacing the bridge deck. To tear up the old pavement, construction crews used a technique called hydrodemolition. This consisted of using high-pressure water cannons to remove the asphalt surface from the bridge deck. While this procedure is fairly common, the water used in the process becomes contaminated and must be disposed of properly. Incredibly, the decision was made to temporarily store this wastewater inside the empty pontoons that kept the bridge afloat.

In defense of the engineering crews, the pontoons had been designed to hold a certain amount of water to safeguard against leakage and the wastewater could be discharged into the pontoons so long as the water levels were carefully monitored.

However, on Thanksgiving Day in 1990, it was clear that somebody had made a serious blunder. A storm had pummeled the city of Seattle over the weekend, causing rain and lake water to accumulate on the bridge. Normally, this wouldn’t be a problem, but the hydrodemolition crews had left the doors to the bridge pontoons open. This caused water to enter the pontoons, and caused the water levels in some of them to exceed the critical levels. By the time crews realized that there was a problem, the crews couldn’t pump the water out of the pontoons quickly enough. What happened next came as no surprise: the Lacey V. Murrow Bridge sank to the bottom of Lake Washington.

A thorough and complex investigation by some of the world’s leading failure analysts arrived at a remarkably simple conclusion: floating bridges will sink when you fill their floats up with water. Fortunately, this engineering blunder resulted in no deaths or injuries, but the damage to the bridge was estimated at $69 million. In 1993, the Murrow bridge was rebuilt, and it continues to be in service today, thanks in no small part to the fact that the bridge pontoons haven’t filled up with water.


Historic Bridge Disasters Caught On Film

People have been obsessively filming bridge collapses for over 70 years. Here is some footage of classic disasters that look like they could have been caused by kaiju.

Honeymoon Bridge or The Upper Steel Arch Bridge (also known as Fallsview Bridge), Niagara Falls, Ontario, collapsed after an ice storm on 27 January 1938 due to huge ice pressure against the abutments.

Tacoma Narrows Bridge or "Galoppin' Gertie", between Tacoma and Kitsap Peninsula, Washington. It was collapsed in under 40 mph (64 km/h) wind conditions only four months after its opening, on November 7, 1940. The only casualty was a dog who had been left in a stalled car by its owner.

The collapse was recorded on 16mm Kodachrome film by Barney Elliott, a local camera shop owner and can be seen after 3:15 here:

Part of the second longest floating bridge on Earth named Lacey V. Murrow Memorial Bridge (I-90 Bridge) across Lake Washington from Seattle to Mercer Island, Washington, sinking after the Thanksgiving Day floods on November 25, 1990.

The workers noticed on November 24 that the day was about to sink but on the next day more than one-third of the bridge (2,790 ft or 850m) was sank.


A car-free alternative to a hellish commute

While there’s much more that can be discussed on the technical side (and Times transportation reporter Mike Lindblom does a fantastic job at this), it’s also worth focusing on the impact that connecting Seattle with the Eastside will have on commuters in this congestion-plagued metro area.

Once complete, the 14-mile East Link Extension will ferry commuters from downtown Seattle’s International District/Chinatown to Bellevue, an affluent Eastside satellite city, in just 15 minutes. A ride on East Link from the University of Washington, north of downtown Seattle, to Mercer Island is expected to take 20 minutes. Sound Transit anticipates 50,000 daily riders will hop on East Link for a quick, reliable and headache-free commute — that's a whole lot less cars on the road in a sprawling, historically car-dependent town that recently ranked 10th worst in the nation based on time spent sitting in traffic.

Trains departing from the line's western terminus at International District/Chinatown station — this downtown transit hub is an existing stop on the north-south Central Link line and will serve as a major transfer station — will run parallel with I-90 through the Mount Baker Tunnel, across the Homer M. Hadley Memorial Bridge and beneath Mercer Island’s Aubrey Davis Park, an innovative freeway lid park that covers a portion of the interstate as it passes through the largely residential island. Exiting Mercer Island, trains will then cross the East Channel Bridge, a short fixed bridge that spans Lake Washington’s tech millionaire mansion-lined East Channel. From there, East Link veers away from I-90 and heads north toward downtown Bellevue and the line’s eastern terminus at Overlake, an area just south of downtown Redmond.

The first phase of Sound Transit's East Link Extension will include 11 stations, many with park and ride facilities. Eventually, it will expand even further northward to downtown Redmond.

The 4.3-mile Northgate Link Extension, which expands Central Link from the University of Washington to Seattle's northern patchwork of neighborhoods, is also under construction with an anticipated opening in 2021. In the final planning stages are two additional Central Link extensions, both slated to open in 2023 — the same year that East Link Extension and its game-changing Lake Washington crossing will be up and running. One sees Central Link climb north from north Seattle to the cities of Shoreline and Lynnwood while a southern extension will service commuters in the cities of Kent, Des Moines and Federal Way.

What's more, early this spring Sound Transit announced plans to power its growing light rail system with 100 percent wind energy starting in 2019. Albeit smaller, Sound Transit's wind-powered rail scheme is similar to one that the Dutch government announced in 2015.

“The commute’s getting worse for everybody, I’m seeing it on the 90 for sure,” Brady Wright, a resident of the Eastside city of Issaquah who commutes daily to downtown Seattle for work, tells Q13. “Not being with their families and not being able to do the things you want to do is a big issue, so if you can get an hour back, a half-hour back every day, that’s what people care about.”


Watch the video: The Lacey V. Murrow Memorial Bridge is Reopened After Disaster September 15, 1993