Earthquake could destroy 520 bridge, too, study says

An Article By LARRY LANGE

So you thought the Alaskan Way Viaduct was on shaky ground? Now you can worry about the state Route 520 bridge, too.

A recent engineering analysis, quietly discussed among state transportation officials and planners, says a magnitude-6.5 earthquake in the wrong spot could take out both structures.

The analysis says the viaduct fronting Elliott Bay and the bridge crossing Lake Washington have about the same ability to withstand the kind of major earthquake that occurs on average every 210 years. It is widely accepted that this region is at risk of catastrophic quakes.

To put it bluntly, a quake ranging in magnitude from 6.5 to 7.2, located close to the Earth's surface and near the spans, could destroy either structure or both.

The odds of this actually occurring have not been determined, state bridge engineer Patrick Clarke said.

Last year's major earthquake, centered near Olympia, registered a magnitude 6.8 but was centered 35 miles underground and 60 miles to the south -- too far away to destroy either span. Still, it was forceful enough to damage both, and to close the viaduct for several days for inspections and repairs.

Losing the bridge and viaduct, besides being deadly, could cripple traffic for years.

More than 225,000 drivers now use the two bridges every day, and would be forced to use side streets or other already-strained highways.

Rush-hour traffic backups could routinely extend south on Interstate 5 as far as the Boeing Access Road or east on Interstate 90 as far as Interstate 405, said Morgan Balogh, the state's regional traffic operations engineer.

"It gets ugly in a hurry, I'm sure," said Les Rubstello, manager of the state's Trans-Lake Washington study examining ways to improve mobility in the 520 corridor.

Replacing the 520 bridge could cost from $1.8 billion for four lanes to $7.4 billion for eight lanes, according to recent state estimates. Construction, depending on the option chosen, could last from nine to 11 years.

That the 520 bridge is as quake-vulnerable as the viaduct was startling news to some.

It was "new information for me," said King County Councilman Dwight Pelz, chairman of the council's Transportation Committee and a key player in planning a regional ballot measure to pay for major highway and transit improvements.

The quake analysis actually has been around for several months and was known to state officials and to some members of an advisory committee discussing whether to rebuild or replace 520's Evergreen Point Bridge.

Rubstello said the state didn't formally release details to avoid sounding "like we were crying wolf twice" after much-publicized reports about the viaduct's vulnerability to tremors.

In February, state Transportation Secretary Doug MacDonald urged legislators and Gov. Gary Locke to set aside money to plan replacements for both the viaduct and 520 bridge.

The letter did not mention the earthquake risk but said the 520 bridge is vulnerable to high winds and waves, which could break it apart.

"I've been flapping my lips at every meeting that it's an unsafe facility," said Redmond Mayor Rosemarie Ives. "Nobody wants to listen."

The quake analysis "serves to move 520 (replacement) up on the regional priority list," Pelz said.

Doing this, however, could reignite controversies about the effects of a bigger new bridge on the shorelines it connects. And some, including transit advocate Peter Hurley, want to see more detailed information before they agree that replacing the bridge makes more financial sense than retrofitting it to better resist earthquakes.

Engineers have long said that a major quake could fatally damage the viaduct, a 2.2-mile, double-deck structure that carries state Route 99 along the Seattle waterfront from the port docks to Aurora Avenue.

They have said the viaduct, which carries about 110,000 vehicles on an average weekday, could collapse if ground gives way under part of it, or if concrete cracks and support columns shear.

In a report issued a year ago, a team of engineers recommended replacing the viaduct, saying retrofitting it to meet modern earthquake standards didn't make sense.

That report came four months after an earthquake did more than $1.7 million in damage to the viaduct, cracking it and prompting crews to close parts of it for several days while it was shored up.

The same Feb. 28, 2001, earthquake that opened cracks in the viaduct did minor damage to the 520 bridge, loosening bolts in a joint on the western approach span.

A 1993 earthquake-evaluation study concluded that the tops of the 520 bridge's approach supports near each shoreline, filled with concrete five feet down from the top, would bend enough in an earthquake to hold up.

But that's no longer accepted. Below those solid "caps," the supports are hollow shells with 5-inch outer walls. State officials said researchers in California later became skeptical about how well hollow columns would hold up.

After a tug and barge hit and shattered one of the 520 bridge columns two years ago, Washington state engineers re-evaluated the earlier conclusion.

And in a memo three months ago, two state engineers said the caps wouldn't bend enough in an earthquake to keep the bridge supported.

That conclusion also was included in a brief internal state Transportation Department report in January. This said that even though the double-deck viaduct and the floating 520 bridge are built differently, the earthquake risks to the two structures when faced with the 210-year earthquake "are almost identical."

Rubstello said state analysts are just beginning to calculate how motorists would react to the simultaneous loss of both structures. Balogh, the state engineer, said backups would be longer on I-5 and I-90 and congestion would worsen on other highways as drivers tried to compensate for the loss of the two spans.

"You're not going to sit on the freeway for an hour. You're going to risk it on an arterial" (street), he said.

Some think the earthquake risk makes the 520 bridge a higher replacement priority. State officials have said retrofitting the 520 bridge for safety is not worthwhile because of its age, though they did do $1.14 million in retrofitting work in 1999.

Even people in Seattle's Montlake neighborhood, where the bridge's west approach is located, agree it should be replaced, said Jonathan Dubman, president of Montlake Community Club.

But the question is: With what? The advisory committee hasn't decided how many lanes a new span should have. That's a big issue in Dubman's neighborhood where, depending on the width of a new bridge, people living 200 feet from it now "could be as close as 20 feet to the new highway."

"The neighborhood would support an effective transportation solution that would improve the quality of life along the (520) corridor and through the region," Dubman said. "But we have some work to do to figure out a solution."

Dubai's Mile-Long Super Arch Bridge

Dubai is going ahead with another ambitious project which is a super arch bridge. Dubai's next super structure will stand higher than the George Washington Bridge (604 ft.) but fall short of San Francisco's existing Golden Gate Bridge (746 ft.).

100 Years Bridge Oberndorf - Laufen

Bridge construction has gone back along way in history

Oberndorf has witnessed a large number of devastating floods during the last centuries. The first record of a bridge being washed away dates back to 1316. The damage was often caused by flotsam which was caught between the wooden bridge pylons and forced the water to dam up. Ultimately the bridges were often just washed away. During the last decade of the 19th century four floods cased great damage, and a decision was made to relocate the town to a more elevated plateau.

The Bavarian Laufen and Austrian Oberndorf developed the plan to construct a stable bridge made of stone and iron incorporating a greater span. As the bridge was in close proximity to both the old town square of Laufen and the new centre of Oberndort, an aesthetic design was implemented.
The two-pylon construction had three apertures, the largest of which was on the Austrian side to allow for shipping needs. The construction was made of 648 tonnes of Martin River iron ore, with a chain-like curved upper cable and a straight lower cable. The facing of the pillars and decorative elements required an additional 67 tonnes of material to ensure a pleasing design. Eagles with spread wings were placed upon the bridge portals, adding to the elegant impression of the construction. The bridge was inaugurated on the 2nd of June 1903 in a collective festival of inhabitants from Laufen and Oberndorf.

Sungai Johor Bridge

Expand Image

The Sungai Johor Bridge will definitely be the longest cable stayed bridge in Malaysia

The cable-stayed bridge has a single central plane of cables in a harp configuration.

Construction of the cable-stayed bridge across the Johor River began in 2006; the bridge was first planned in 1996 but the Asian currency crisis put paid to it at the time. The bridge will connect Kong Kong on the western bank to Teluk Sengat in the east.

The preliminary and detailed design and engineering work was carried out by COWI Consulting Engineers and Planners AS and Ranhill Consulting Sdn Bhd for Senai Desaru Expressway Berhad (the concession holder). Three Ranhill engineers spent six months in Denmark with COWI designers to develop the design of the bridge.

The construction was undertaken by Ranhill Engineers and Constructors Sdn Bhd, foundations were constructed by Ranhill Antara Koh Sdn Bhd, the steel construction was the remit of Jawala and MBEC. Waiko Engineering Sdn Bhd are construction subcontractors, the stay cables and incremental launching of sections were contracted to VSL International.

"The new road will be a four-lane dual carriageway and will improve access across the region of Johfor."

BRIDGE STRUCTURE

The main span of the bridge is 500m and the pylon height is 150m above the surface of the river. The cable-stayed design of the bridge is in a harp configuration but in a single central plane (only one set of stay cables). This means that the cables are in a near-parallel arrangement, by virtue of the fact that the cables are attached to various points on each of the two ‘A’ shaped concrete pylon towers.

Each tower has a foundation of 34-bore 2m-diameter steel cased piles. The result of this is that the height of attachment of each cable on the tower is similar to the distance from the tower along the roadway to its lower attachment.

The middle 739m of the bridge has a composite deck with a 250mm-thick precast concrete deck slab and a closed structural steel skirt (3.5m deep). There are two 484.5m deck sections on either side of the central section and these consist of a concrete box girder structure.

Worlds Longest cable-stayed bridge span is completed

The worlds longest cable stayed bridge was officially opened on 30 June 2008.

The two cantilevers of China's Sutong Bridge have been connected, creating the world's longest cable-stayed bridge span. COWI has provided construction management on the project, among other services.

China's Sutong Bridge crosses the Yangtze River upstream from Shanghai. Its 40-metre wide bridge deck will carry a six-lane road plus emergency lanes. The main span of the bridge is 1088 metres, making it the longest cable-stayed bridge in the world.

COWI is providing services that include design assistance and design review, design of scour protection, aerodynamic investigations, construction control and construction management.

The Sutong Bridge, China, close to completion.
Image gallery

Ahead of schedule

COWI chief project manager Lars Thornfeldt Sørensen has been with the project since it began in 2003.
He says, "The project has run smoothly and the closure of the main span was completed nine months ahead of schedule. The significant volume of river traffic could have been a major problem but the Chinese authorities organised timed closures to allow for the hoisting of bridge girder segments."

The final bridge segment connecting the two spans was floated down river and hoisted into place at the beginning of June.

Long cantilevers

The connection of the bridge cantilevers is more than just a ceremonial occasion. Prior to connection, the two record long cantilevers were sensitive to strong winds and therefore it was important to join the cantilevers before the beginning of the typhoon season. Joining them creates a far stronger structure.

Millau Viaduct – World's Tallest Bridge

Extreme Engineering Marvel

Mankind has certainly moved on to the next challenge of constructing on what was thought to be as the impossible by our predecessors. Credits to the Engineers.

To me there are few things more impressive than being on a man-made structure, such as a very tall building or a bridge, and viewing blue sky above and clouds below. Of, course for this to occur the structure has be be rather high and the clouds low.

This is why I was immediately impressed when a friend sent me pictures of the Millau Viaduct, which crosses the valley of the Tarn River valley near the city of Millau in the mountains of southern France.

Normally it is the high mountains that present a challenge to engineers building roads that connect two or more points. However, in case of the Millau Viaduct, the mountain area through which the A75 autoroute, also known as la Méridienne, passes is apparently rather high most of the way until it reaches the Tarn River valley.

Bridge with blue sky above and clouds below.

Bridge spans valley of the Tarn River.

 

A Joint Franco-British Project

As can be seen from the picture at the right, one has to traverse a long, winding road down the mountain on one side of the valley and then immediately repeat the process while climbing up the mountain on the other side of the valley.

In addition to the kilometers / miles and time added by the trip down into the valley and back up into the mountains, time was also lost in the past to traffic congestion in the town and on the two lane bridge across the Tarn River. It is estimated that the bridge over the valley has shortened the driving distance between the Paris and the Mediterranean coast of France by 100 kilometers (about 62 miles) and, during the summer tourist season, reduced travel time by as much as four hours.

Construction of the bridge was a joint Franco-British project with help from companies in other European countries. Financing for the 394 million Euro (U.S. $524) project was provided by the French construction firm Eiffage. As a result of corporate mergers*, the Eiffage frim includes the firm that built the Eiffel Tower in Paris which, at the time of its completion in 1887, was the tallest structure in the world. This is obviously a company with long experience in being involved with construction of structures of record setting size. British architect Norman Foster designed the bridge, which has come to be viewed both as a work of art as well as a construction marvel, while the French bridge engineer, Dr. Michel Virlogeux, provided the engineering design.

While planning began in the late twentieth century, actual construction did not begin until December 2001 and its 2005 target completion date was achieved a little early when it was formally dedicated on December 14, 2004 and opened to traffic on December 16, 2004.

The Millau Viaduct is an artistic and engineering marvel. It currently holds the record for having the highest piles (the pilers rising from the ground and supporting the bridge from below) of any bridge in the world with its highest being 244.96 meters (803.7 feet) and the highest mast (the pilers rising up from the top of the bridge and holding the suspension cables) which towers 343 meters (1,125 feet) above the roadbed of the bridge. It also has a claim to having the highest roadbed of any bridge in the world with its roadbed reaching 270 meters (885.8 feet) above the river below.

However, the roadbed of the Royal Gorge Bridge in Colorado in the United States tops this with its roadbed which towers 1,053 feet (321 meters) above the river below. Based upon height of roadbed, the Royal Gorge Bridge is the highest in the world while based upon mast height, the Millau Viaduct is the highest in the world. Regardless of which is the highest, the Millau Viaduct is the clear winner in terms of length and beauty.

Famous Bridges

Look back into history of some of the famous bridges around the world

Look up to the tallest bridge in the United States at the Royal Gorge Bridge in Colorado. It is the tallest suspension bridge in the world, looming above the Arkansas River at 1,053 feet. You can even walk across the bridge’s wooden planks, if you can deal with the vertigo you may experience. Only taking six months to build, it cost $350,000 in 1929. This bridge was built with tourists in mind, not as a transportation mode. It is at the top of the list for visited attractions in Colorado.

See St. Petersburg Cathedral, The London Eye, Canary Wharf and so much more from the London Tower Bridge walkways in London, England. The two towers span over the Thames River with two glassed in walkways for pedestrians to walk. Previously, the London Bridge was the only way in and out of England’s capital city. As the only movable bridge on the Thames, it moved up and down over 1,000 times a year after it first opened in 1894. Today, very few ships travel down the Thames River and it only opens about 100 times annually.

Cross the Brooklyn Bridge by car and you will be among 144,000 other vehicles daily. This bridge boasts several “firsts” in the world of bridges. It was the first suspension bridge to use steel cable wires in its construction, and it was also the first to use caisson devices in explosions. When it was built in 1883, it was the longest suspension bridge at 3,460 feet. However, today the Japanese Akashi Kaikyo Bridge at 12,626 feet is the longest suspension bridge in the world.

Ride in a railway car over the Garabit Viaduct Bridge from the Garabit valley to the south of France. This famous red bridge was built from steel beams with triangle shaped holes in a truss pattern. This allowed the windy area’s bridge to remain stable rather than swaying when the wind hit it. This bridge was designed by none other than Gustave Eiffel, known as the famous architect of France’s Eiffel Tower.

There is enough cable wire from the Golden Gate Bridge in San Francisco to circle around the world several times. The men that worked on the bridge had a special name attached to them, the “Halfway to Hell Club.” That's how dangerous their jobs were. A safety net was strewn under the workers. It saved the lives of 19 of the bridge builders during it’s construction. A million vehicles, and counting, have gone over the Golden Gate since it was built in 1937.

Observe the remains of the Tacoma Narrows Bridge at the National Register of Historic Places. Its remains were dredged from Puget Sound for safe keeping. After its demise, bridges were never built in the same way again. When this bridge was completed in the 1940s, it got the name “Galloping Gertie” because of its rocking action. It actually made drivers and passengers car sick while driving over it. Thankfully, no lives were lost when it finally fell apart in 42 mph winds and crashed into the water below. The solid girders used in the construction of the Tacoma Narrows Bridge caused it to act in the unstable manner. A new type of construction eased the wind and kept bridges from excessive swaying.

Chappel Viaduct in England

It’s amazing how people can construct such a massive structure back during the old days.

Renowned as being the second largest brick built structure in England, the first being recognised as Battersea Power Station, the Chappel Viaduct is situated near Wakes Colne in Essex and spans the picturesque Colne Valley. It presently still supports the Sudbury to Marks Tey line which regularly connects with trains to and from London's Liverpool Street Station along the main line.

The foundation stone for this man made wonder was laid on the 14th September 1847. A bottle containing a newly minted sovereign, a half-sovereign, a shilling, a sixpence and a four-penny piece was placed underneath this stone. This bottle and all its contents were stolen shortly after the laying ceremony; the culprit was caught after he tried to pass over a brand new sovereign coin in the nearby Rose and Crown public house.

Chappel Viaduct is 1,066ft long and some 5 to 6 million bricks are believed to have been used in its construction. A work force of 606 men known at the time as 'navvies' were employed to complete the work which took two years, this was relatively fast for such a large structure. The Viaduct has 32 arches; each having a span of 30ft and at its maximum the height is 75ft. Although so many bricks were used in the construction, to save money and to cut down on weight, the piers were left hollow.

The engineer of the viaduct was Peter Schuyler Bruff and his plan was for the line to continue on as far as Ipswich in Suffolk, but the railway company did not have sufficient funds for this. Bruff later built the line himself and is also credited for founding the Essex seaside resort of Clacton-on-Sea.

On the 2nd July 1849, the first passenger train crossed the viaduct from Colchester to Sudbury carrying an official party. A large crowd greeted the honoured guests at Sudbury despite its station still being unfinished.

To this day Chappel Viaduct is in daily use by trains and is well worth a visit if you are in the area. It attracts many tourists and visitors every year and is a highly photographed structure. Bordering the viaduct is The Chappel Millennium Green and as the name suggests this was opened to celebrate the Millennium. It contains a walk around area and children's play area which should keep the kids amused while you take in this wonder.

The proposal of the railroad viaduct construction system utilizing the self-compacting high strength and high durable concrete.

A new innovation in viaduct Construction Technology

It will a revelation for the way we construct viaduct in the future

Title;The proposal of the railroad viaduct construction system utilizing the self-compacting high strength and high durable concrete.

Author;TAKEDA YASUSHI(Tekken Constr. Co., Ltd.) SAKANOUE HIROSHI(Aoki Corp.) SUMI HIROYUKI(Fujita Corp.) OZAWA KAZUMASA(Univ. Tokyo, Graduate School, JPN)

Journal Title;Kensetsu Manejimento Mondai ni kansuru Kenkyu Happyo, Toronkai Koenshu

Journal Code:X0097A

ISSN:

VOL.19th;NO.;PAGE.59-62(2001)

Figure&Table&Reference;FIG.7, TBL.3, REF.3

Pub. Country;Japan

Language;Japanese

Abstract;To convert from a minimum material to minimum manpower, the research of the structure which replaces a past beam slab type viaduct is actively done in the railway viaduct. Recently, it is necessary to increase a concrete quality and durability because the accident concerning the concrete of the tunnel and the viaduct occurred. Moreover, it is expected to become cheap in the life cycle cost though an initial construction cost of the self-compacting high strength and high durable concrete structure is comparatively expensive. Then, to establish the construction system utilizing the self-compacting high strength and high durable concrete, authors paid attention to the term of works shortening and the labor saving, and did the cost analysis of the railway viaduct. As a result, the structural type utilizing the self-compacting high strength and high durable concrete almost becomes equal with a past structure in an initial construction cost. Moreover, the structural type confirmed becoming in the life cycle cost the advantage by the high durability of the self-compacting high strength and high durable concrete. (author abst.)