@jhnblgr, I think the question we have now is whether NDS EQ 3.4-3 applies to birdsmouth/seat cuts that can use the prescriptive depth allowances of depth/4 and depth/10. My understanding is that notches and birdsmouths create a reentrent corner with a high stress point that can cause the member...
Yes, @Eng16080, I was assuming the birdsmouth is a notch. It would be great to have clarification on whether it is or is not a notch.
I would still assume that the depth/4 for sawn or depth/10 for engineered lumber applies to the birdsmouth.
Yes, we do that or use VPC's when contractors request using TJI's at the roof but then there are other issues involved such as inward thrust of the walls. Seat cuts are nice because they help transfer the load downward and negate the horizontal component of the load. I didn't realize how...
Yes, @jhnblgr, that would likely work. I ran into this single issue but I am now wondering if I should be changing the way I calc all of my rafters, which would have a noticeable impact on project cost.
I just noticed that NDS 8.4.1.1 actually calls for a depth/10 max notch at supports, yikes...
It is 366 at 16" oc spacing, so the roof snw is only 285, my bad. That includes sliding snow from above.
I could see using equation 3.4-3 for notches within the beam span but at the supports it seems excessive. Only a 1" notch would be allowed for a 9-1/2" LVL.
You are right, @Eng16080, I missed that reference. Thank you.
I have a 1-3/4x9-1/2 LVL @ 16" OC spanning 10' with a 366psf snow load, 15psf dead load, Cd=0, Cr=1.15. I am getting that this rafter is ~40% overstressed in shear w/ Fv=285psi.
I am hoping to have some corroboration or denial of a new outlook on birdsmouth/seat cut notches for rafters. The approach has always been a max notch of depth/4, which is currently supported in the Wood Frame Construction Manual (WFCM) 2.5.1.1.4. The 2018 NDS mentions in 3.2.3.2 that the...
We are eliminating the top chord and it will likely be a smaller frame with a secondary hss or wide flange header below the top chord. I would assume that the slip connection would only need to be on the siding. We can design the secondary header for wind loading as well.
We are designing a two-story moment frame in a new home with the upper bay housing a Marvin Windows Ultimate patio door, with windows above. The 28' wide moment frame is supporting large roof snow loads of ~4200plf. It looks like all of the Marvin ultimate doors require an 1/8" max deflection...
I just found this back-to-back WSWH option from Simpson: Link
I know this is a tested system but it certainly seems more feasible knowing that they allow it.
Hello!
I have a client who offered an unconventional concept for using two double-sided shearwalls back-to-back to form a high load shearwall (2 studwalls, 4 sheets of ply total). We are considering this for a an exterior wall application on the lower level of a three-story home, in lieu of a...
