Robert wrote:
Every time I cross the GW I ask myself 2 questions. How much longer will this bridge last? What if this was hit on September 11?
The bridge is undergoing a major rehab right now including replacement of the suspender cables and replacement of the main cable sleeves (protective wrapping of the main cable bundles) and inspection and installation of a dehumidification system for the main cables and anchorages. The bridge just turned 85 and with the maintenance work it should make it to another 85.
Regarding attacking the bridge. Knocking out the decking would impede traffic but it is repairable. Main cables and the towers are enormous and very heavily built. They have to be just to hold themselves together. A suspension bridge consists of four main components, the towers, the anchorages, the main suspension cables, and finally the deck. The Tacoma Narrows collapse (Galloping Gertie) destroyed the deck while the rest of the bridge was still intact.
I'm often amused by the "apocalyptic" portrayals of suspension bridge destruction depicted in pop culture (TV, movies, graphic arts). I really enjoy the ones where the main suspension cables are somehow severed and the portions of the deck below the "intact" parts are still there. The "artists" have no idea how the bridge woks and probably aren't even aware that the main suspension cables are tens to hundreds of thousands of miles of strands of wire each of which is about a pencil lead's diameter.
One of the most disconcerting things about walking across the GW is feeling the bounce in the deck as every large heavy vehicle rolls by. The deflection is noticeable. You can't feel this when you are in a car of bus driving across the bridge for a variety if reasons. It just feels odd that something that massive moves around at all.