|View single post by Herb Kephart|
|Posted: Sun Feb 20th, 2011 10:12 pm||
|36" is 144' in 1/48
Even with the lightest loading (10000# driver loading, cars 1000#/ft), a plate girder would have to be overly deep to carry the load at that span.
The beam in itself would be heavy enough to pose a problem getting cranes of sufficient capacity to set the beam.
The shorter span sections of the bridge would have to be designed heavy enough to support the cranes, and the beam.
On a beam of that size, the weight of the beam itself would be a large amount of the total bridge carrying capacity.
The middle span would be more likely built as an inverted truss deck girder- with trusses 14-16' deep---still a spindly looking bridge.
Just don't expect me to walk across it.
Fix it again, Mr Gates--it still works!"