New Highway 520 Pontoon Bridge
New Highway 520 Pontoon Bridge
(OP)
I have been trying to follow the recent controversy here with the leaking concrete pontoons and I am in a quandry.
For those who are unfamiliar with the situation, this bridge, a concrete "floating" bridge, is the sixth in the state of Washington of its kind, two on Hood Canal, and the fourth for Lake Washington, considering additions and replacements.
The pontoons are being fabricated in Aberdeen on the coast of Washigton, and being floated to the site on Lake Washington between Seattle and Bellevue. Apparently, the pontoons have developed cracks and leaking, both in the casting yard, and on site. The bridge is now delayed 6 months in it's completion until the summer of 2015. Lawsuits have been filed at this point to discover how the rep[airs are to be paid for and by whom.
What I cannot understand, is with the four previous bridges over the last 50 to 60 years of history with the original floating bridge for I-90 over Lake Washington, why is this a problem now? If details that worked were changed, why re-invent the wheel?
I have heard allegations regarding the contractor, state inspectors, and ths like, but I don't know what to believe here. Any additional insight Bridgebuilder?
For those who are unfamiliar with the situation, this bridge, a concrete "floating" bridge, is the sixth in the state of Washington of its kind, two on Hood Canal, and the fourth for Lake Washington, considering additions and replacements.
The pontoons are being fabricated in Aberdeen on the coast of Washigton, and being floated to the site on Lake Washington between Seattle and Bellevue. Apparently, the pontoons have developed cracks and leaking, both in the casting yard, and on site. The bridge is now delayed 6 months in it's completion until the summer of 2015. Lawsuits have been filed at this point to discover how the rep[airs are to be paid for and by whom.
What I cannot understand, is with the four previous bridges over the last 50 to 60 years of history with the original floating bridge for I-90 over Lake Washington, why is this a problem now? If details that worked were changed, why re-invent the wheel?
I have heard allegations regarding the contractor, state inspectors, and ths like, but I don't know what to believe here. Any additional insight Bridgebuilder?
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com





RE: New Highway 520 Pontoon Bridge
RE: New Highway 520 Pontoon Bridge
http://www.eng-tips.com/viewthread.cfm?qid=334389
RE: New Highway 520 Pontoon Bridge
My question still stands. After all that experience with success with the other bridges, why so many problems with this one? Something is fishy.
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: New Highway 520 Pontoon Bridge
RE: New Highway 520 Pontoon Bridge
http://www.youtube.com/watch?v=gm0YQ3vuyyY
RE: New Highway 520 Pontoon Bridge
A large portion of the Hood Canal bridge sank back in the 80's too during a storm, but not because of cracks in the concrete structure. Instead, it sank because a maintenance worker did not properly re-install the accessway cover plates in the bridge deck, and the compartments flooded leading to the sinking.
I am only referring to the inherent cracking of the sidewalls, intersections and bottom of the pontoons. That should not happen in my opinion, pumps provided or otherwise.
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: New Highway 520 Pontoon Bridge
I will not comment any further.
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: New Highway 520 Pontoon Bridge
http://seattletimes.com/html/localnews/2020439320_...
RE: New Highway 520 Pontoon Bridge
http://www.wsdot.wa.gov/NR/rdonlyres/4A835908-743D...