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Vrs for panel buckling from O86 11.5.1(c) is calculated with a complicated set of equations that ultimately require only the variable parameters listed below. Their values are output in the Detailed Shear Wall Design report for each wall segment.
Plywood or OSB properties Ba,90, Ba,0 and Bv
The axial stiffness values Ba,90 and Ba,0 and shear-through-thickness rigidity Bv come from O86 Tables 9.1 ,and 9.2 for plywood and 9.3 for OSB. There is a value each thickness and no. of plies for plywood and panel marking for OSB,
Sheathing thickness t
The actual thickness of the sheathing panel in mm.
Panel Sizes a and b
Larger and smaller dimensions of the "crtical" panel a and b, respectively,are used both directly in the equation for panel buckling strength vpb and in the exponent -a in the Kpb factor in that equation.
As the buckling resistance gets larger as the smallest dimension of the sheet used gets smaller (because b in the denominator of the vpb), the critical panel within a segment is the largest one. Therefore, full 4 x 8 sheets are used for those segments that are larger than 4 feet wide for vertical sheathing and 8 feet for horizontal orientation. For smaller segments, the size of the largest component panel is determined, for example a 6-foot segment uses 4’ x 6’ for horizontal sheathing and 4’ x 8’ for vertical. A segment 3 feet wide uses 3' x 8' for vertical and 3' x 4' for horizontal.
Service Condition Factor KS
For wet service conditions as input in the Design Settings, the program applies a KS factor of 0.80 for plywood from O86 Table 9.4. Wet fabrication conditions to not apply to plywood. Wet service conditions are not allowed for OSB.
Treatment Factor KT
Due to the rarity of use of treatment for plywood and OSB, the program does not include an input for treatment and the treatment factor KT is always 1.0.
Duration Factor KD
This is set to 1.15 for both wind and seismic.