The new 520 bridge s construction site on lake washington is seen in november looking west. Despite some leaks and cracks, pontoons for the new highway 520 bridge are solid enough for construction of highway columns and other attachments to proceed, state engineers say. New state route 520 floating bridge opens to traffic on april 25. Cracked 520 bridge pontoons headed for drydock repairs. Kurt schlosser geekwire distressed boaters or swimmers will have. First 520 bridge pontoon to go through ballard locks this. Wsdot will be held accountable for 520 bridge mistakes, but the tax payers will have to foot the bill. The longest, state route 520, connects seattle to points east over lake washington, which dips to 214 feet deep. The grand opening of the new sr 520 evergreen point floating bridge was a historical event attended by over 50,000 people on april 2 and 3, 2016. Inside pontoon v one of the 360footlong floating concrete structures that will hold up the 520 bridge white lines show where contractor kiewit made prior repairs to fill in cracks and stop. But the state department of transportation says drivers dont need to worry.
Sr 520 bridge replacement and hov program floating bridge. Risk management for sr 520 pontoon construction hdr. New highway 520 pontoon bridge msquared48 structural. It was the longest floating bridge in the world until 2016. Sr520 pontoon construction general construction company. Are shortcuts compromising safety of new 520 bridge. The washington transportation department says more cracks have been found in pontoons under construction in aberdeen for the new highway 520 floating bridge on lake washington at seattle. Cracks in some pontoons have forced costly repairs. Kurt schlosser geekwire like a battleship made of concrete, its quiet and cold at the bottom of a giant bridge pontoon. Two of the four cracked pontoons for the new highway 520 bridge will be towed back out of lake washington and hoisted aboard dry docks where engineers think they can be fixed faster than if they. Work has been under way to address cracking discovered last month. In pontoon v, a 360foot longitudinal pontoon, inspectors found a leak at. Pontoon construction project project management plan.
What it takes to keep a 7,700foot floating bridge from doom. Washington transportation secretary paula hammond announced this week that wsdot is. The floating bridge on seattles route 520 already has the distinction of. Wsdot says cracks in new sr520 pontoons are par for the. The new sr 520 floating bridge is supported by 77 concrete pontoons that form the floating foundation of the new bridge.
The evergreen point floating bridge, officially the governor albert d. Hdr served as risk manager for the sr 520 bridge replacement and hov program for the washington state department of transportation. How do earthquakes affect the floating section of the sr 520 bridge. Its aging pontoons had sunk a foot from their original placement and had developed thousands of cracks, which, though repaired, still left them. Washington state department of transportation kiewitgeneralmanson delivered an integrated deck support superstructure for this, the worlds. The washington state department of transportation and its contractors have reached agreements on the cost of repairing four pontoons from the first construction cycle and modifying another four. You may have heard about some issues with the large concrete pontoons being built for the new 520 bridge across lake washington.
Sr 520 bridge replacement and hov program washington. In 2012, wsdot identified cracks and other problems with the first batch of completed. A pontoon bridge or ponton bridge, also known as a floating bridge, uses floats or shallowdraft boats to support a continuous deck for pedestrian and vehicle travel. Cracks delay work at floating bridge project in washington. New trail for washington park arboretum to mitigate sr520. How to build the worlds longest floating bridge route 520 lake. Why did wsdot replace the old sr 520 floating bridge and landings. Some cracking is normal, but a harsh internal audit by the state department of transportation found mistakes in concretedrying temperatures for the first batch of six pontoons for the new highway 520 bridge. Expert panel formed to determine cause of new cracking on. Additional work on the 520 bridge pontoons could cost tens of millions of. Millions of dollars must be spent to fix the pontoons being built for a new 520 bridge, transportation officials said tuesday, after underwater inspections revealed that the pontoons worst cracks. If a 100year storm event were to occur, the pontoons are designed to prevent large cracks from developing that would allow water to leak in and sink the bridge. The 7,710footlong 2,350 m floating span is the longest floating bridge in the world.
The entire raft was pushed as a single unit, like a large 1,000footlong ship, to the west end of the bridge where it was joined to pontoon e and eventually the westernmost pontoon a. Discover sr 520 floating bridge key facts and common questions. Washington state, however, knows a little about how to make so much mass actually buoyant. Past storms sheared off components on the old sr 520 floating bridge and caused pontoon cracks and leaks that required. Work at the sr 520 pontoon construction project site in aberdeen started in february 2011. More than 115,000 vehicles cross the aging sr520 floating bridge between seattle and bellevue on a daily basis, and it was imperative that the washington state department of transportation wsdot provide commuters a new, safer and more modern bridge to withstand potential seismic activity and severe weather. More cracks found in new pontoons for 520 bridge kepr. Investigation uncovers widespread leaks on new 520.
On the surface of lake washington, construction workers on the new highway 520 floating bridge forge ahead, even as divers perform underwater inspections to find out if the first batch of pontoons is still leaking. Fixing 520 bridge pontoon cracks to cost tens of millions. The first pontoon for the new state route 520 floating bridge will be towed through the ballard locks this weekend on its way to lake washington. Pontoons the foundation of a floating bridge bridge pontoons are the foundation of a floating bridge. Kiewitgeneral, a joint venture kg was selected as the best value contractor to. The buoyancy of the supports limits the maximum load they can carry most pontoon bridges are temporary, used in wartime and civil emergencies. Rosellini bridge, carries washington state route 520 across lake washington from seattle to its eastern suburbs. Instead, it sank because a maintenance worker did not properly reinstall the accessway cover plates in the bridge deck, and the compartments flooded leading to the sinking. Structure magazine construction of the worlds longest. Pontoon construction project project management plan august 2010 part 2. Work on 520 bridge continues as divers check fixes, cracks. Several of them sprung leaks and cracks after the cement set in aberdeen.
The washington transportation department says more cracks have been found in pontoons under construction in aberdeen for the new highway 520 floating bridge on lake washington. Sr 520 bridge replacement and hov program floating. Sr 520 pontoon and floating bridge construction sites tacoma floating bridge aberdeen february 2017. Drinking on the job, leaks and cracks with the new 520 bridge pontoons, and now the problem solvers have uncovered alleged construction flaws at safeco field and with the iconic bay bridge in. Sr520 floating bridge and landings project youtube. Because of the lakes deep waters and mushy bottom, the foundations for a. The washington state department of transportation and its contractors have reached agreements on the cost of repairing four pontoons from the first construction cycle and modifying another four pontoons from the second cycle for the new state route 520 floating bridge. Wsdot says more than 30,000 linear feet of cracks have been repaired in those pontoons since the. Sr 520 bridge replacement and hov program julie meredith, p. Concrete was poured last week to add five columns to the giant end pontoon. Pontoon assembly and fastening, to form the floating bridges deck, began in 2014 and. Formerly spanned lake washington in washington state, carrying state route 520 from seattle to medina.
In pontoon v, a 360foot longitudinal pontoon, inspectors found a. If a 100year storm event were to occur, the pontoons are designed to prevent large cracks. Julie meredith sr 520 program director sr 520 bridge replacement and hov program washington state department of transportation 600 stewart street, suite 520. Investigation uncovers widespread leaks on new 520 pontoons. Pontoon cracks will push 520 bridge completion to 2015 the state plans to spend tens of millions of dollars in contingency funds to repair existing cracks and prevent. The new floating bridge, shown from the west, is now estimated to be completed by september 2015. Afloat for more than 50 years, the fourlane bridge. But the state department of transportation says drivers dont need to. His grand scheme of a concrete pontoon floating bridge across lake. Rosellini bridge, and commonly called the sr 520 bridge or 520 bridge, was a floating bridge in the u. Komo investigators uncover more problems with kiewit. How to build the worlds longest floating bridge route. The evergreen point floating bridge, also known as the 520 bridge and officially the governor.
Construction of the worlds longest floating bridge structure. Washington owns the four longest floating bridges in the world. The evergreen point floating bridge, also known as the 520 bridge and officially the governor albert d. Divers map cracks in pontoon for new 520 bridge the. The sr 520 bridge crosses lake washington, linking seattle and its neighboring cities to the east. A toll bridge until 1979, its common name is the 520 bridge or evergreen point floating bridge. Wsdot will not reject leaking 520 bridge pontoons komo. Repairs have been successfully implemented on four pontoons under construction in aberdeen for the new state rte. Massive pontoons support the new sr 520 floating bridge.