Rigid Diaphragm Analsyis

[EDub24]

Hello! I'm brushing up on my hand analysis of a rigid diaphragm and have a couple quick questions. I found a really useful paper that goes step-by-step through the analysis of a rigid diaphragm and how to calculate the inherent torsion however I'm not sure a couple equations given in the paper are correct. If you skip to section 11.1 they give equations for how to determine the wall shears for a seismic load in the x-direction. Equation 20 makes sense to me and the numbers work out however I think the signs are backwards for equation 21 (the shear forces in the walls parallel to the y-direction). If you look at my quick sketch I put together of the building in the paper, it appears that wall 1 should have a shear in the negative y direction and wall 3 should be in the positive y-direction. However if you look at table 6 (page 7) in the paper, they show that wall 1 is in the positive y-direction and wall 3 i is in the negative y-direction. If you look at section 11.2 (seismic in the y-direction) there is a similar mistake for the walls parallel to the x-direction. It seems like there should be a negative sign for equation 21 (and 24 for y-direction loading). Am I missing something here?

Also, in section 11 they state that it is standard practice to add the absolute value of the accidental torsion to the torsional shears. Is that really standard practice? That doesn't make sense to me. I think you should take the maximum value of the +/- accidental torsion to obtain the maximum value.

Thanks for the help!

http://files.engineering.com/getfil...le=Rigid_Diaphragm_Analysis_-_Louie_L_Yaw.pdf

http://files.engineering.com/getfil...7-8ce8-4467-9c5b-9d4cb63f5b9e&file=Layout.pdf