Curved Beam - Residual Stress
Curved Beam - Residual Stress
(OP)
Folks,
I have an interesting problem at hand. A canopy was designed too short and it needs to get extended. The original canopy was a cantilevered truss. We are now adding a support close to the 2/3 point of the truss and attaching/extending a curved W12 to form the new canopy. See attached section.
My questions are as follows:
1. I am going to calculate wind loads in a myriad of ways (open building, overhang, parapet etc etc) and determine an optimum number to use. Any suggestions?
2. The member is architecturally shown to be a bent the hard way to an outside radius of 7'-0". On first thoughts, it appears to be too tight and may not even be possible to be bent. Any additional info?
3. If the beam can be bent, how much residual stress will be built into it and how much will be available for design? The downforce will be opposite to the residual stress, but the uplift will induce more stress in the direction of the bending.
I have an interesting problem at hand. A canopy was designed too short and it needs to get extended. The original canopy was a cantilevered truss. We are now adding a support close to the 2/3 point of the truss and attaching/extending a curved W12 to form the new canopy. See attached section.
My questions are as follows:
1. I am going to calculate wind loads in a myriad of ways (open building, overhang, parapet etc etc) and determine an optimum number to use. Any suggestions?
2. The member is architecturally shown to be a bent the hard way to an outside radius of 7'-0". On first thoughts, it appears to be too tight and may not even be possible to be bent. Any additional info?
3. If the beam can be bent, how much residual stress will be built into it and how much will be available for design? The downforce will be opposite to the residual stress, but the uplift will induce more stress in the direction of the bending.






RE: Curved Beam - Residual Stress
RE: Curved Beam - Residual Stress
RE: Curved Beam - Residual Stress
RE: Curved Beam - Residual Stress
RE: Curved Beam - Residual Stress
RE: Curved Beam - Residual Stress
RE: Curved Beam - Residual Stress
I believe the W12's will be much easier to bend but flange thinning will probably occur. Depending on bend radius it could be significant enough to account for in the design. Some of the fabricators could advise you on what to expect. Advanced Bending Technologies, Chicago Metal Rolled Products Company, White Fab Inc, and Abina Pipe Bending Co are some fabricators that have advertized recently in Modern Steel Construction.
Here's two good sources of information on steel bending.
www.modernsteel.com/backissues Free down loads of back issues. Look for "Bending Considerations in Steel Construction" Oct. 2009 MSC. There is another article on curved steel in the Oct. 2010 issue. Curved steel has been a popular topic recently.
www.aisc.org/benders Provides links to bender/rolers and has free downloads of publications about curved steel.
RE: Curved Beam - Residual Stress
RE: Curved Beam - Residual Stress
Seems to me this would be easier than bending.
tg
RE: Curved Beam - Residual Stress
RE: Curved Beam - Residual Stress
The list can be found at the link below along with some other useful information if you don't already have it.
http://www.aisc.org/content.aspx?id=18112
RE: Curved Beam - Residual Stress
RE: Curved Beam - Residual Stress
sure it's unusual and not efficient and maybe can't be formed as originally intended or needs some post-processing but that's the challenge (isn't it ?)
RE: Curved Beam - Residual Stress
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