BTStructural
Structural
- Mar 28, 2022
- 6
Soooo, a contractor forgot to install a supporting steel column in a residential construction project, the home is all framed up with roof on, and the supporting steel column cannot now be installed directly below the steel beam as they misplaced the steel beam's location and it falls near the end of a garage door whose operation would not work anymore if we put the column directly below the beam. Quite the pickle.
This is in a high snow region. Using 1.2D + 1.6S I'm designing for a reaction of 44kips. I'm thinking that the best way to pick up the load is with a welded shear tab to a beam stiffener, allowing me to pick up the load very near the center of the beam (see detail).
From what I've seen the welded shear tab connection isn't specifically approved outside of a moment connection but is widely used in retrofit situations. Studies seem to have shown that the rigidity of the shear tab connection is more influenced by other factors than welds vs bolts anyways, such as thickness of the plate. However, the plate is a bit longer than the typical conventional condition for shear tabs I believe, and so I'm considering using the column cap over the shear tab to stiffen the connection. I guess that is one dilemma - stiffen the connection here due to the extended shear tab or not stiffen so as to allow rotation of the shear tab and help keep it a pinned connection. I feel like the weld handshake going on here will almost create a regular shear tab connection already (as opposed to the more extended shear tab scenario) but I plan on tying the top of the column into the floor's wood diaphragm regardless.
Anyways, thoughts on this connection would be appreciated. I may be able to weld a smaller WT section at the bottom to act as a seat, not sure that would really do much though (?) and space is limited to allow the garage door to still function.
On the plus side, the home made it through the winter without issue so maybe none of this is critical in the end but I designed it a certain way and I'd like to have the column in with a proper connection
[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1682134244/tips/r1_n2ske7.pdf[/url]
This is in a high snow region. Using 1.2D + 1.6S I'm designing for a reaction of 44kips. I'm thinking that the best way to pick up the load is with a welded shear tab to a beam stiffener, allowing me to pick up the load very near the center of the beam (see detail).
From what I've seen the welded shear tab connection isn't specifically approved outside of a moment connection but is widely used in retrofit situations. Studies seem to have shown that the rigidity of the shear tab connection is more influenced by other factors than welds vs bolts anyways, such as thickness of the plate. However, the plate is a bit longer than the typical conventional condition for shear tabs I believe, and so I'm considering using the column cap over the shear tab to stiffen the connection. I guess that is one dilemma - stiffen the connection here due to the extended shear tab or not stiffen so as to allow rotation of the shear tab and help keep it a pinned connection. I feel like the weld handshake going on here will almost create a regular shear tab connection already (as opposed to the more extended shear tab scenario) but I plan on tying the top of the column into the floor's wood diaphragm regardless.
Anyways, thoughts on this connection would be appreciated. I may be able to weld a smaller WT section at the bottom to act as a seat, not sure that would really do much though (?) and space is limited to allow the garage door to still function.
On the plus side, the home made it through the winter without issue so maybe none of this is critical in the end but I designed it a certain way and I'd like to have the column in with a proper connection
[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1682134244/tips/r1_n2ske7.pdf[/url]
