Bearing stiffeners on crane-runway beams
Bearing stiffeners on crane-runway beams
(OP)
Hello all!
I am designing a crane runway beam and it seems like I will need bearing stiffeners to prevent web crippling/yielding. My question would be, how would I space these bearing stiffeners? The crane of course moves through the length of the beam, making web crippling/yielding a problem throughout the length. Would I have to choose a beam with a thicker web as opposed to using bearing stiffeners? If not, I ask again, how do I determine a suitable spacing for these stiffeners? Thanks!
I am designing a crane runway beam and it seems like I will need bearing stiffeners to prevent web crippling/yielding. My question would be, how would I space these bearing stiffeners? The crane of course moves through the length of the beam, making web crippling/yielding a problem throughout the length. Would I have to choose a beam with a thicker web as opposed to using bearing stiffeners? If not, I ask again, how do I determine a suitable spacing for these stiffeners? Thanks!






RE: Bearing stiffeners on crane-runway beams
RE: Bearing stiffeners on crane-runway beams
I didn't mean the stiffeners have to be placed continuously.
RE: Bearing stiffeners on crane-runway beams
There is a great publication from CISC called "Crane Supporting Steel Structures Design Guide" by R.A. MacCrimmon. It is an excellent resource, complete with design examples and model detailing. I would encourage you to obtain a copy if you are going to be doing many crane rails. Available as a free download from http:
Cheers,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...
RE: Bearing stiffeners on crane-runway beams
Cheers,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...
RE: Bearing stiffeners on crane-runway beams
Second, the cost of adding all those stiffners is higher than the cost of a thicker web.
RE: Bearing stiffeners on crane-runway beams
I will change the profile of the beam to one that has adequate web thickness.
To youngstructural:
I'm looking at the first design example right now and one thing that is standing out is that the book calculates "Mi" and also the equation that they used for "Mu" is quite different than S16. Are these equations from AISC? Thanks!
RE: Bearing stiffeners on crane-runway beams
RE: Bearing stiffeners on crane-runway beams
This is indeed from AISC; Please see "Design Method", p. 35 for an explanation of the term Mi... Essentially it is Mu.
Hope that helps!
Regards,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...
RE: Bearing stiffeners on crane-runway beams
I should really read my previews more carefully!
Sorry for any possible confusion...
Regards,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...
RE: Bearing stiffeners on crane-runway beams
RE: Bearing stiffeners on crane-runway beams
RE: Bearing stiffeners on crane-runway beams
RE: Bearing stiffeners on crane-runway beams
I haven't practiced in Canada for a few years now, but am a P.Eng. (Ontario). Working on getting my CPEng (New Zealand) right now... Will probably write the IStructE exam while I'm down here as well.
Are you still practicing in Canada?
And no worries at all; More than glad to help out. That should be why we're all here. *smiles*
Cheers,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...
RE: Bearing stiffeners on crane-runway beams
As to the original question about bearing stiffeners, I agree with YS and JAE that they are not normally needed along the beam. Stiffeners are usually required at the columns. Runway beams for heavy duty cranes, particularly hot metal cranes, are frequently fabricated welded girders, and these usually do have web stiffeners.
RE: Bearing stiffeners on crane-runway beams
Cheers,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...
RE: Bearing stiffeners on crane-runway beams
RE: Bearing stiffeners on crane-runway beams
RE: Bearing stiffeners on crane-runway beams
In my experience that's why web stiffeners are normally stopped short of the bottom flange. I've also seen details where the stiffeners are machined to fit tight to the underside of the top flange and only welded to the web, again for fatigue concerns.
Hokie
The stiffeners do have some beneficial effect on the bending in the web due to load eccentricity (eg AS4100.18, Cl.5.7.3.4).
RE: Bearing stiffeners on crane-runway beams
RE: Bearing stiffeners on crane-runway beams