Wood Shear Wall Sitting on a Beam
Wood Shear Wall Sitting on a Beam
(OP)
Hi ,
I am an EIT working on a project and some of the shear walls are sitting on beams on 2nd floor because they are not lining up with shear walls below. Since there is an overturn at the shear walls it is causing compression and tension on the beam so I am designing the beams to bear these loads.
I am designing the beams on StruCalc and there is no option for seismic load choice. Do you guys think that would be okay to consider these compression and tension forces caused by seismic force on shear wall ,as a live load just for the sake of beam design ?
Thank you,,
I am an EIT working on a project and some of the shear walls are sitting on beams on 2nd floor because they are not lining up with shear walls below. Since there is an overturn at the shear walls it is causing compression and tension on the beam so I am designing the beams to bear these loads.
I am designing the beams on StruCalc and there is no option for seismic load choice. Do you guys think that would be okay to consider these compression and tension forces caused by seismic force on shear wall ,as a live load just for the sake of beam design ?
Thank you,,






RE: Wood Shear Wall Sitting on a Beam
(I'd suggest you delete your other post about this because this one explains your situation better, in my opinion)
RE: Wood Shear Wall Sitting on a Beam
RE: Wood Shear Wall Sitting on a Beam
RE: Wood Shear Wall Sitting on a Beam
Make sure you check all the elements in the load path.
RE: Wood Shear Wall Sitting on a Beam
@slickdeals I am not clear about designing the diaphragm to transfer the loads to the offset shear wall. Could you please elaborate it ?
Thank you so much !
RE: Wood Shear Wall Sitting on a Beam
You also have a shear that has to be transferred to adjacent walls. Refer to 12.10.1.1 that talks about adding the transfer shear.
Imagine the diaphragm as a beam spanning between the walls on the 1st floor. This beam will have a point load equal to the shear in the wall you are stopping. You should design the diaphragm not only to cater to the force that it has at the 2nd floor but also this transfer shear.
Figure out what your shear is on the 2nd floor diaphragm. This would give you a unit shear w1.
Then figure out the additional shear coming from the wall stopping at the 2nd floor. Distribute this shear based on a simple beam analysis and you will get a unit shear w2.
The connection of the diaphragm at the 2nd floor should be designed for w1 + w2 (if you are not using over-strength factor, then you will need to amplify w2 by 25%, assuming you are in seismic design category D or higher, per ASCE 7 Section 12.3.3.4)
The below link walks through in detail.
http://www.woodworks.org/wp-content/uploads/2015-W...
RE: Wood Shear Wall Sitting on a Beam
1) Figure out the factored load being delivered to the beam from the wall.
2) Adjust the load entered into your software so that, when it's fudge factored as live load, the result is the same.
Defining your lateral bracing may be important here since you may induce compression in the bottom flange.
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.