Steel Channel Cantilever Beam
Steel Channel Cantilever Beam
(OP)
Let's say you had a series of steel channels embedded 16 inches into a large concrete footing and the channels cantilevered vertically from the top of the footing about 5 ft. Clear spacing between channels is 12 inches.
These are being designed as precast panel storage "racking" blocks, with the idea being the panels are placed on their edge between these channels and wood blocking is wedged between the channels, to hold the panels upright. The loads applied near the tips of the channels (at the wedge points) are from wind and from tilt of the panels and or footings. Channels are loaded in the strong direction.
The way I see it, the channels are prevented from twisting and rotating by a moment connection at the footing. However the part of the channel that is above the footing is not braced in any direction, so I'm worried about lateral torsional buckling of the channel under loads. Can I use the general unbraced flexural resistance eqns for steel beams to check these channels, which are cantilevered? What would the unbraced length be, 5 ft or 10 ft, (because its a cantilevered and free to translate at the end - (like k = 2.0)?
How about loading the channels slightly off the shear center? The load will come into the channels on the flanges, close to the webs, and the shear center of a channels is probably about 1/2" to 1" off of the cl of the flanges.
PS - Cdn steel design code, but I believe the US code is very similar.
These are being designed as precast panel storage "racking" blocks, with the idea being the panels are placed on their edge between these channels and wood blocking is wedged between the channels, to hold the panels upright. The loads applied near the tips of the channels (at the wedge points) are from wind and from tilt of the panels and or footings. Channels are loaded in the strong direction.
The way I see it, the channels are prevented from twisting and rotating by a moment connection at the footing. However the part of the channel that is above the footing is not braced in any direction, so I'm worried about lateral torsional buckling of the channel under loads. Can I use the general unbraced flexural resistance eqns for steel beams to check these channels, which are cantilevered? What would the unbraced length be, 5 ft or 10 ft, (because its a cantilevered and free to translate at the end - (like k = 2.0)?
How about loading the channels slightly off the shear center? The load will come into the channels on the flanges, close to the webs, and the shear center of a channels is probably about 1/2" to 1" off of the cl of the flanges.
PS - Cdn steel design code, but I believe the US code is very similar.






RE: Steel Channel Cantilever Beam
RE: Steel Channel Cantilever Beam
I'm going to give this a bit of thought, and probably post again. I've done similar calculations for stairs with just one stringer (where a person walking down one side of the stairs puts a torsion load on the stringer).
Cheers,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...
RE: Steel Channel Cantilever Beam
RE: Steel Channel Cantilever Beam
If you are loading the channels through the flanges, there will be torsion on the channels.
RE: Steel Channel Cantilever Beam