RAM Elements CMU module appears to have an error for calculating or displaying the allowable shear stress for bearing wall. See the screenshot below. Based on my own hand calcs the allowable shear stress would be 50 psi and the utilization ratio appears to agree with that as well. See the attached files. Version 16.06.00.187.
PDF
Example NonBrgWall ASD_TMS402-16.msw
Seth Guthrie - any help on this one?
There is some out of plane moment at the top (due to the parapet continuity). In the Equation 8-29 for Fvm the M/Vdv term is greater than zero (I calculate 0.81) so Fvm comes out to be 57 psi. Quick hand calc below:
Seth,
I looked into this a little more. My first suggestion was incorrect, but I think that RAM Elements still has an error. I think the calculation for allowable shear for both segments is incorrect, but segment 2 gets the correct number due to the forces (see below). See below for the calculation for segment 1:
I think gammag should be 1.0 since this is not for a shear wall (in-plane shear), but rather checking a wall for out of plane shear (TMS 402-16 Sect 8.3.5.1.2)
dv should be 7.625 in. Per TMS 402-16 Chapter 2, dv is the actual depth of the member in the direction of shear being considered. dv is not equal to d (distance to centroid of reinforcing). In this case, dv would be the thickness of the wall.
taking this into account
M/(V*dv) = 0.409
Fv_max = 124.6 psi (interpolated between Eqn 8-23 and 8-24 of TMS 402-16 per Sect 8.3.5.1.2(c)) (see below)
Fvm = 73.4 psi (per TMS 402-16 Eqn 8-26) (see below)
So the number for segment 1: Fv = 73.4 psi
I would guess that the calculations for segment 2 are incorrect as well, but the max shear equation controls and due to the small shear force for segment 2, the factor of M/(V*dv) is greater than 1, but per TMS402-16 would be taken equal to 1 (would be equal to 1 even if dv was taken equal to 3.8125" in RAM Elements). Segment 2: Fv = 50.3 psi
Hello Jeremy,
The Masonry Design module is considering correctly the gamma values for bearing and shear walls. However, as you mention there is a glitch in the Fvm calculation for TMS 402-13 onwards as we are not correctly determining the design code to switch between d and dv. You should notice that until TMS 402-11 d was used to determine Fvm (below TMS 402-11 excerpt).
And for TMS 402-13 the change was done from d to dv
We have already done the fix and the Segment1 Fv = 0.073 ksi Segment2 Fv = 0.050 ksi. The fix will be released in RAM Elements v16.7 end of June 2022.