Economical and safe support system?
Economical and safe support system?
(OP)
Hi All,
Just to preface, I'm a Mechanical Engineer by profession and not a structural engineer. I would like to get some feedback from all you structural experts on a particular concern as outlined below:
I have also attached an image for clarity.
What I have is a platform 3' wide running down the length of a 24' long W10X39 beam. The continuous load for the platform is 155 lbs/linear.ft. Right now, I have 4 of the shown supports evenly spaced within the 24' beam span. The support consists of a C6X6.2 channel attached to the beam as shown with (1) 3x3x3/16 angle. Is this method considered safe and economical from a structural engineers standpoint? Or is there another more efficient and cost effective method?
The 1400 lbs shown is the concentrated load calculated for such a condition for the (2) center supports of the 24' beam span.
I thank you all in advance for any comments and feedback.
Best Regards,
CSCPE24.
Just to preface, I'm a Mechanical Engineer by profession and not a structural engineer. I would like to get some feedback from all you structural experts on a particular concern as outlined below:
I have also attached an image for clarity.
What I have is a platform 3' wide running down the length of a 24' long W10X39 beam. The continuous load for the platform is 155 lbs/linear.ft. Right now, I have 4 of the shown supports evenly spaced within the 24' beam span. The support consists of a C6X6.2 channel attached to the beam as shown with (1) 3x3x3/16 angle. Is this method considered safe and economical from a structural engineers standpoint? Or is there another more efficient and cost effective method?
The 1400 lbs shown is the concentrated load calculated for such a condition for the (2) center supports of the 24' beam span.
I thank you all in advance for any comments and feedback.
Best Regards,
CSCPE24.






RE: Economical and safe support system?
RE: Economical and safe support system?
RE: Economical and safe support system?
Civilperson, Do you mean add more supports? Or totally change the design?
RE: Economical and safe support system?
Plus wide flanges have almost zero torsional rigidity.
Not a good detail.
RE: Economical and safe support system?
Would the angle not pick up on the end moment? The angle will either be bolted or welded to both the channel and also the wide flange beam.
RE: Economical and safe support system?
RE: Economical and safe support system?
Yes, the 155 plf actually is derived from 40 psf for live load.
Assuming that I can only fashion some sort of support from the W10X39 while still adhering to the layout with the platform right beside the beam, would welding a tube to the underside of the beam flange to pick up on the loads be better then?
Thanks.
RE: Economical and safe support system?
RE: Economical and safe support system?
1. Through the angle-to-walkway connection (rigid)
2. Then through plate bending in the vertical leg of the angle (very flexible)
3. Then through the weld from the angle to the WF flange tip,
4. Then through the vertical web of the WF as it torques against the 3x3 clip angle(flexible)
Everything would bend like crazy.
Instead of a W10x39, a 10x10 tube could be welded to the supporting beam below and horizontal channels (or tubes) could be welded to the side face of the 10x10 tube to form a cantilever system. The cantilevered members should be 8" deep or so to avoid bending in the side wall of the 10x10 and get closer to its top and bottom flanges.
RE: Economical and safe support system?
RE: Economical and safe support system?
RE: Economical and safe support system?
In addition to previous comments, I also don't see the connection between the channel and w section providing much torsional restraint to the channel. This gives a large lateral torsional buckling length for the cantilevered channel. Can't say offhand if this causes capacity problems or not, but it is something I would try to avoid.
RE: Economical and safe support system?
I was hoping to rely only on some sort of support members that can be attached to just the single W10x39 to pick up on the walkway but I guess it's not a good idea whatsoever.
There is actually another W10x39 to the left of the first one that is not shown. I'm thinking of just bridging the top of the two W10x39 with 5x2x1/4 rectangular structural tubes. These tubes would then act as the supporting members for the walkway. Although this would create an uplift force on the far side W10x39 but I think the loads will be well within the allowable design constraints.
RE: Economical and safe support system?
RE: Economical and safe support system?
Now you are on the right track.
herewegothen,
A knee brace from what? A knee brace from the beam bottom flange doesn't change the fact that the beam is no good in torsion.
RE: Economical and safe support system?
RE: Economical and safe support system?
Why not stick with the c6 channel, that way you can bolt it directly to the top of the two W10s with 2 bolts to each. Just an idea.
RE: Economical and safe support system?
That's a good idea. However, based on the overall support plan, welding will be easier because field drilling holes will be too cumbersome and preparing the steel with pre-drilled holes takes too much work since the support spacings won't have a consistent pattern.
RE: Economical and safe support system?
Have you checked how the walkway material connects to your tubes?
RE: Economical and safe support system?
Welding will be the most likely scenario. Angle clips will be field welded to connect the walkway to the tubes.