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Bridge specs

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Chris,
For heat-curved beams, my 1993 specs (they are the design specs) in section 10.15.2 specify a minimum radius of horizontal curvature of 150 feet and the larger of
 
R = 14 b D/[(sqrt Fy)X tw}]
 
R = 7500 b/(Fy X)
 
Fy ksi
D is web height
b is widest flange width
X is ratio of area of both flanges to total area
tw is web thickness
R is radius in INCHES  (tricky bastards)
 
In addition, if flange thickness exceeds 3 inches or flange width (b) exceeds 30 inches, the minimum radius is 1000 feet.  This to me qualifies as a very coarse step function.
 
For tighter radii, of course, they just cut the flanges curved and flex the web.
 
HTH,
Mike Hemstad,
bridge engineer a long time ago.
 
> Does anyone here have a copy of the AASHTO Standard Specifications For
> Highway Bridges? (Note that this is not the design specs.) Apparently,
> Article 10.15.2 of Division 1 states something about the minimum radius
> that
> a girder can be heat curved. If anyone can help me with this, I would
> appreciate it.