HSS Bearing on Steel Seat Connection (Corbel)
HSS Bearing on Steel Seat Connection (Corbel)
(OP)
I have a situation where a temporary column is required and due to contractor constraints a steel corbel or seat connection is required (see attached/below) to support column adjacent to concrete wall. My question is besides checking the anchorage to the concrete wall, weld connection of stiffener to seat/sideplate, is there a localized effect I need to consider on the HSS bearing on the baseplate? In other words even if there is pure axial load, will the HSS want to bend around the stiffener? Also, is there any other effects I may not be considering?






RE: HSS Bearing on Steel Seat Connection (Corbel)
The bearing plate ought to be designed as a base plate for the HSS so as to prevent the HSS walls from crippling over the stiffener. Alternately, you could make the HSS walls thick enough that they wouldn't cripple even if there were no bearing plate. Lastly, you could have two stiffeners an place one under each HSS wall. That would be structurally ideal but unnecessary in my opinion. Chances are, things wouldn't line up anyhow.
If you haven't already, the stiffener should be checked for combined stresses and buckling.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: HSS Bearing on Steel Seat Connection (Corbel)
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries
www.americanconcrete.com
RE: HSS Bearing on Steel Seat Connection (Corbel)
Maybe need to consider buckling on the seat.
Also there's out of plane moment on the anchorage group because the HSS eccentricity. (HSS center-anchorage reaction line).
Even if it just a temporary column i will try not to consider just axial load, but clearly it's on you criteria and project requirements.
RE: HSS Bearing on Steel Seat Connection (Corbel)
I would also see what happens if he outside tip of your corbel deflects say 1/16"... slippage at bolts, deformation per M + V, this may cause a little bit more moment in your HSS... i have no feel for this at all so i would check but that is only because i have no judgement on the effect.
So i assume the wall can handle the moment? and the connections?
RE: HSS Bearing on Steel Seat Connection (Corbel)
If the column is not capable of carrying P.e then the upper two fasteners should be through bolts with nut and washer on the far face of wall and the wall must be adequate to resist the applied moment.
BA
RE: HSS Bearing on Steel Seat Connection (Corbel)
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: HSS Bearing on Steel Seat Connection (Corbel)
Point taken. To avoid brittle anchor failure modes, perhaps the upper two anchors should be through bolts designed to carry a tension of P(e + t/2)/d where P is column load, e is eccentricity from wall face, t is wall thickness and d is the effective depth of connection.
BA
RE: HSS Bearing on Steel Seat Connection (Corbel)
This helped me avoid through bolt anchors as BA mention as an option (couldn't place anchors deep enough to get a sufficient failure cone which led me to investigate through bolts). Plus I don't have a solid understanding of the bearing effects on the bolt i.e. do you consider full length of bolt as bearing on concrete in a through bolt situation? And there would no doubt be some possible spalling at interface between concrete surface and bolt that would induce bending in the bolt.
The ideal situation would be to place column over wall, but that was not an option.
RE: HSS Bearing on Steel Seat Connection (Corbel)
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: HSS Bearing on Steel Seat Connection (Corbel)