allowable shear stress

huangyhg

allowable shear stress
i am using an allowable shear stress of .85*2*sqrt(fc) to get allowable shear stress in psi. i noticed that factor changed in the new aci to .75, but they do allow it in appendix c if you use there load factors. i assume it is ok to use .85 for now. does anyone have any comments on this?
t.

just be consistent.  you can use the higher resistance factors if you use the historically higher aci load factors (e.g. 1.4d+1.7l).  but you must use the lower resistance factors if you use the lower asce 7 load factors (e.g. 1.2d+1.6l).
i would second what taro says.