520 bridge pontoon cracks in the foundation

House approves 520 bridge tolling strange bedfellows. The first stage of the sr 520 floating bridge replacement project was the construction of 77 concrete pontoons in 2011 and 2012 by kiewitgeneralmanson at two purposebuilt facilities in aberdeen and tacoma. West approach bridge north questions and answers view of the sr 520 floating bridge, looking west from medina. The floating bridge on seattles route 520 already has the distinction of. In 1957, a concrete floating bridge was built across lake okanagan at kelowna in south central british columbia, canada. The repairs for cycle one have been underway since june to keep bridge construction moving along. Due to the dramatic increase in population, the bridge now carries an average of 115,000 vehicles per day. Pontoon construction project builds a new casting basin facility in aberdeen and 33 concrete bridge pontoons to replace the existing sr 520 floating bridge. In pontoon v, a 360foot longitudinal pontoon, inspectors found a. One of the more important aspects of a floating bridge is that it stays afloat.

Why did wsdot replace the old sr 520 floating bridge and landings. The pontoon construction project created hundreds of local jobs and supported the local economy in and around aberdeen through the purchase of supplies and supporting services. A toll bridge until 1979, its common name is the 520 bridge or evergreen point floating bridge. The demerara harbor bridge in georgetown, guyana is the worlds fourthlongest floating 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. Wsdot mistakes on the bridge across lake washington will likely hurt other state projects. State fires top bridge engineer over 520 pontoon flaws. More problems found with troubled 520 bridge project. In the distance, pier 36, the west approach to the new floating bridge, is. Repair costs, and revised schedule for sr 520 pontoons. The evergreen point floating bridge, also known as the 520 bridge and officially the governor.

Pontoon assembly and fastening, to form the floating bridges deck, began in 2014 and. Sr 520 floating bridge and landings project american society of civil engineers asce. Structure magazine construction of the worlds longest. Wsdot says more than 30,000 linear feet of cracks have been repaired in those pontoons since the. Structure magazine floating cofferdam for repair of the. Andrew garber, new 520 bridge by 2014, state says, the seattle times, march 3, 2008. What it takes to keep a 7,700foot floating bridge from doom. Documentation of the evergreen point floating bridge was. The pontoon was constructed in grays harbor and moved. 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. Seattle the latest 520 bridge pontoon is expected to come through the ballard locks on its way to lake washington, according to a wsdot press release. Evergreen point bridge written narrative 520 history.

State fires top bridge engineer over 520 pontoon flaws the seattle. High above lake washington, and with state route 520 in the background, construction crews carry on with their day as they continue to make progress in building roadway support structures on the top of pier 1. Repairs and design modifications are coming to the pontoons that will support the new state route 520 floating bridge, the state department of transportation announced tuesday. How to build the worlds longest floating bridge route. Wsdot announces sr 520 pontoon design changes and repairs. Wsdot has released cost figures for repairs and design changes to the first pontoons built for the new 520 bridge. The first of the new 520 bridge pontoons departs the ballard locks and continues its journey to lake washington on saturday, august 11, 2012. Formerly spanned lake washington in washington state, carrying state route 520 from seattle to medina. Sr 520 pontoon construction project completed march. 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. The first six concrete pontoons to support a replacement s. Past storms sheared off components on the old sr 520 floating bridge and caused pontoon cracks and leaks that required. The 7,710footlong 2,350 m floating span is the longest floating bridge in the world, as well as the worlds widest measuring 116 feet 35 m at its midpoint.

Work has been under way to address cracking discovered last month. Timevariable tolling on the existing sr520 bridge began in 2011 to help fund. Expert panel formed to determine cause of new cracking on. At the time of its completion in 1963, the bridge was to carry an estimated 65,000 vehicles a day to and from the city centre. In pontoon v, a 360foot longitudinal pontoon, inspectors found a leak at. 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. The sr 520 bridge crosses lake washington, linking seattle and its neighboring cities to the east. Sr520 floating bridge and landings project youtube. Afloat for more than 50 years, the fourlane bridge. Wsdot and our contractor, kiewitgeneral, are committed to high quality in these pontoons so that they will form the foundation for the worlds longest floating bridge and serve the public well for many decades to come, said s. Rosellini bridge, carries washington state route 520 across lake washington from seattle to its eastern suburbs. Paige cornwell and mike lindblom, 520 bridge reopens after 8 injured when traffic sign falls on bus, ibid. The bridge shown in figure 1 above that is marked 520, is known as the state route sr 520 floating bridge. Sr 520 bridge replacement and hov program floating.

Opened to traffic in april 2016, the bridge replaces the previous sr 520 floating bridge, which was completed in 1963 and had reached the end of its. His grand scheme of a concrete pontoon floating bridge across lake. Wsdot says cracks in new sr520 pontoons are par for the. Problems on sr520 floating bridge causing delays, cost. But much bigger cracks and leaks are now showing up as a result of bad design and failure in oversight by wsdot. The evergreen point floating bridge, also known as the 520 bridge and officially the governor albert d. Cracks delay work at floating bridge project in washington. The new sr 520 floating bridge is supported by 77 concrete pontoons that form the floating foundation of the new bridge. The project is the first construction phase of the sr 520 i5 to median. How to build the worlds longest floating bridge route 520 lake.

You may have heard about some issues with the large concrete pontoons being built for the new 520 bridge across lake washington. Its floating length is 2,100 feet, with a design very similar to the lacey v. All of the cracks had been repaired, 520 program director julie meredith told us. Risk management for sr 520 pontoon construction hdr. An equally important objective was to assess and mitigate cracks resulting from thermal stresses induced between curing concrete of different ages and ma. 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. Eastside floating bridge pontoons upcoming construction. Cracked 520 bridge pontoons headed for drydock repairs. 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. Wsdot says cracks in new sr 520 pontoons are par for the course. Problems on sr520 floating bridge causing delays, cost overruns.

The pontoons were floated to the bridge on lake washington via the lake washington ship canal. Are shortcuts compromising safety of new 520 bridge. In 2012, wsdot identified cracks and other problems with the first batch of completed. An untreated underwater crack can let in water at rates of 1 cubic foot per hour, according to a technical report on the bridge. The new 520 bridges construction site on lake washington is seen in. New trail for washington park arboretum to mitigate sr520. Several of them sprung wsdot says cracks in new sr 520 pontoons are par for the course knkx. Small cracks have appeared in at least two the first six pontoons built for a new floating bridge in lake washington, but transportation officials said friday the problem is manageable leaks can. Discover sr 520 floating bridge key facts and common questions. New state route 520 floating bridge opens to traffic on. Investigation uncovers widespread leaks on new 520 pontoons. It was the longest floating bridge in the world until 2016. The new bridge, which should open by 2014, will extend the span from 7578 feet about 1.

The new 520 bridge s construction site on lake washington is seen in november looking west. Rosellinievergreen point bridge, the worlds longest floating bridge, is facing costly delays due to design and construction problems by wsdot and contractor kiewit. But wsdot remains confident in the pontoons structure. Several of them sprung wsdot says cracks in new sr520 pontoons are par for the course knkx. Lake washington congestion management project implements tolls on the existing sr 520 floating bridge, and activates smarter highways features from i5 to i405. The legislation includes authorization for early pontoon construction, the foundation of the 520 bridge construction, early tolling on 520 and the financial support to get the 520 bridge built. According to wsdot, the latest jobs report counted 832 jobs directly connected to the pontoon and floating bridge project sites. Construction of the worlds longest floating bridge structure. The state route 520 floating bridge in seattle, washington. State route 520 bridge concrete construction magazine. That seems like a simple enough design request, and the existing sr 520 bridge over lake washington has met that. This pontoon was the first to undergo posttensioning, which was done to ensure it didnt crack under the pressure of the 105,000 vehicles a day planned for the future 7,710ftlong, sixlane bridge. Mike lindblom, big bill and big delay to fix new 520 pontoons, ibid. Cracks in some pontoons have forced costly repairs.

The new evergreen point floating bridge, which carries state route 520 sr 520, is the worlds longest floating bridge, stretching 7,708. Pontoon assembly and fastening, to form the floating bridge s deck, began in 2014 and. Because of the lakes deep waters and mushy bottom, the foundations for a. Sr 520 program overview pontoon repairs financial update construction updates.