rolling of structural shapes in circular arch

huangyhg

rolling of structural shapes in circular arch
when you roll a structural shape such as w12x40 in a radius of say 6' how does it effect its strength and e?
the strength and elastic modulus is independent of the deflected/curved shape.
you should call a bending shop and confirm that you can actually bend a w12x40 to a 6-foot radius.  if it is not possible or practical then there's no need to worry.  
given that, if the material is cold-worked, you will have some change in the yield but you really have no way to account for it with a hot-rolled shape.  you will also have some distortion of the cross section which gets worse depending on the radius and the cross-sectional geometry.
we once had some c6x8.2# channels rolled the hard way to about a 25' diameter- had some of them where the flanges just ripped off the webs.
with a w12x40 at a 6' radius, if you can't bend it, you can probably fab up an equivalent section out of plate/bar.
i don't have the data to hand, but in uk practice, the yield and modulus are unaffected as the material is empirically similar to that before curvature. the curve shape generates out of plane forces (both bending and shear) which reduce the allowable material stresses available for the primary loads. the magnitude of the additional forces varies with curvature...
also remember to consider carefully the ability of the section to laterally buckle.