Rod - By now you've seen the others in this series and have figured out each of the 20 cables are each attached to the bridge deck's center with ten rising to the left side and ten to the right side. What isn't easily perceived is that they're not connected to the columns, but rather are running actually through them and down to the other side. The Penobscot Narrows Bridge is a cable-stayed bridge over the Penobscot River and replaced an older brigde (still standing). The new 2,120 feet long bridge is one of two bridges in the U.S. constructed recently to utilize a cradle system that carries the strands within the stays from bridge deck to bridge deck, as a continuous element. Each epoxy-coated steel strand is carried inside the cradle in a one-inch steel tube acting independently, allowing for removal, inspection and replacement of individual strands. The cable-stay system was designed with a system that uses pressurized nitrogen gas to defend against corrosion. Additionally, in June of 2007, six reference strands within three stays were replaced with carbon fiber strands - a first in the U.S. Monitoring on the strands will evaluate this material for future use in bridge designs. These engineering innovations helped the bridge appear in the December 2006 edition of Popular Science as one of the 100 best innovations of the year. (Source includeshttp://en.wikipedia.org/wiki/Penobscot_Narrows_Bridge) - Kelly
Rod
19-Nov-2007 06:35
This looks to be a really well exposed shot & it looks great in B&W. What are the spiral ducts being used for?
