Bearing Length for Steel Channel Pinch Beam
Bearing Length for Steel Channel Pinch Beam
(OP)
Good Day,
I am currently working on a project where the client would like to create a 13'-0" opening in an existing 8" thick CMU wall (unknown if fully grouted). I have decided to proceed with designing a steel pinch beam. In my case, I will be using two C12 steel channels that sandwich the CMU with tightened bolts.
My question is how much of bearing length would be required at the ends of the pinch beam? I believe the correct design would be to have the bearing length of the steel beam to be equal in length to a CMU pier to resist the same weight. Then the bolts would need to be checked for similar bearing.
If someone could help direct, it would be greatly appreciated. Thank you!
I am currently working on a project where the client would like to create a 13'-0" opening in an existing 8" thick CMU wall (unknown if fully grouted). I have decided to proceed with designing a steel pinch beam. In my case, I will be using two C12 steel channels that sandwich the CMU with tightened bolts.
My question is how much of bearing length would be required at the ends of the pinch beam? I believe the correct design would be to have the bearing length of the steel beam to be equal in length to a CMU pier to resist the same weight. Then the bolts would need to be checked for similar bearing.
If someone could help direct, it would be greatly appreciated. Thank you!
RE: Bearing Length for Steel Channel Pinch Beam
RE: Bearing Length for Steel Channel Pinch Beam
Sorry, I'll get off my soap box now.
RE: Bearing Length for Steel Channel Pinch Beam
It would be difficult to install a single W-Beam of such long length in the space required. Perhaps it is not impossible though. Perhaps two small W-Beams. I found some youtube videos of really nifty ways contractors have been able to shore a wall to install a new beam.
Back to the pinch beam. I am not as concerned with the CMU above the pinch beam, I am more concerned with the bearing at the end conditions. Meaning that the total end reaction is going to a handful of bolts. Bolts may be strong enough, but the bearing support on the existing CMU is so minimal to be concerning.
Additional input is appreciated. Thank you
RE: Bearing Length for Steel Channel Pinch Beam
RE: Bearing Length for Steel Channel Pinch Beam
https://www.eng-tips.com/viewthread.cfm?qid=434595
I believe a lot of discussion is based on the design of the bearing bolts. But I am concerned with the bearing length of the channels at the ends of the steel. For example, when I design a precast lintel, we like to have 1" of bearing for every 1'-0" of clear span (so a 13'-0" opening would require 13" of bearing at each end). What would the procedure be for the steel pinch beam bearing design?
RE: Bearing Length for Steel Channel Pinch Beam
RE: Bearing Length for Steel Channel Pinch Beam
RE: Bearing Length for Steel Channel Pinch Beam
RE: Bearing Length for Steel Channel Pinch Beam
RE: Bearing Length for Steel Channel Pinch Beam
Ordinarily I use a bearing plate at the end that projects out from the face of the wall to support the steel channels.
Usually are bearing plate is relatively thick (to provide sufficient stiffens) and the cells where it is bearing are grouted solid.
I'm pretty sure that is what bob33 is describing too.
In extreme loading cases I use T_Bat's idea of channels on the sides -OR- I have installed a steel column within the plane of the wall with a wide plate on top (sometimes with gussets, then the pinch beams and then cut the opening.
Seems like the 12:1 ratio is a good starting point but there are many factors that contribute to whether or not the numbers work out.