http://www.garrettsbridges.com/videos/pratt-truss-bridge-video Where model bridge builders of all ages come to learn. Mon, 30 Aug 2010 04:57:47 +0000 hourly 1 http://wordpress.org/?v=3.0.1 http://www.garrettsbridges.com/videos/pratt-truss-bridge-video/comment-page-1#comment-2918 Ndubbs Fri, 06 Nov 2009 15:06:56 +0000 http://www.garrettsbridges.com/?p=696#comment-2918 The bridge most likely failed because there was little torsional bracing in the truss. This led to the bridge swaying to the side during the collapse, which could have been prevented by adding cross bracing between the top and bottom chords. The straight bracing they have between the trusses is not enough to prevent overall torsion. With X-bracing on the top and bottom, the bridge is much stronger laterally (real bridges utilize this for wind bracing). The bridge most likely failed because there was little torsional bracing in the truss. This led to the bridge swaying to the side during the collapse, which could have been prevented by adding cross bracing between the top and bottom chords. The straight bracing they have between the trusses is not enough to prevent overall torsion. With X-bracing on the top and bottom, the bridge is much stronger laterally (real bridges utilize this for wind bracing).

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