See "Concrete "Core" Determination" for the web width (bw) calculations.
Half of the width of bonded ducts and all of the width of unbonded ducts that are located in the shear core are deducted from the bw width to determine the bv width. Where ducts are at different elevations within the core, the elevation with the maximum effective duct width is used to determine bv.
If the section is declared as "post-tensioned", d0 is taken as the maximum of the depth of all tension reinforcement or 0.8D. No check is made to verify that the structure actually is post-tensioned.
If the section is not post-tensioned d0 is taken as the maximum depth of all tension reinforcement.
Ast is taken as the area of longitudinal reinforcement (excluding PT) that is in the tension zone for the cross section forces under consideration.
The vertical component of inclined prestressing tendons, Pv, is ignored (taken as zero).
Flexure-shear Vuc is calculated per 8.2.7.2 (a) (for non-prestressed members the Apt and V0 evaluate to zero).
V0 is calculated as M0/(M*/V*) for both determinate and indeterminate structures.
β2 is taken as 1.0 (no axial force considered).
β3 is taken as 1.0.
Apt is taken as the sum of all post-tensioning (bonded and unbonded) in the tension zone. Vector components of the tendon areas are used for tendons that are not perpendicular to the design section.
Web-shear Vuc is calculated per 8.2.7.2 (b) (for both prestressed and non-prestressed members). The calculation is performed at the centroid of the member, but the net web width (bv) is used to determine the shear stress at the centroid. The balance analysis prestressing forces and the gross section properties are used to determine the axial stress at the centroid.
Vus is calculated per 8.2.10 (a).
No increases of capacity are considered for sections or loads close to supports.
If "beam torsion" is selected, torsion design is also performed (see "Section 8.3 Beam Torsion Design"). Maximum shear capacity is reduced by section 8.3.3. If torsion reinforcement is required, then Section 8.3.4(b) is used to reduce available shear capacity.
Stirrup spacings are reduced by a factor of 0.8 per 8.2.12.4(c).
