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For any diaphragm, where shear is transferred from the diaphragm to a collector, or from the diaphragm or collector to a vertical element of the lateral-force-resisting system, (a) or (b) shall apply:
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are applied:
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(a) Vn is determined according to Eq. (12.5.3.3), and cross-sectional dimensions selected to provide Eq. (12.5.3.4). Acv is determined using the thickness of the topping for noncomposite topping slab diaphragms and combined thickness of cast-in-place and precast elements for topping slab diaphragms.
(b) Vn does not exceed the value determined according to the shear-friction provisions of 22.9 considering the thickness of the topping slab above joints between precast elements in noncomposite and composite topping slab diaphragms and the reinforcement crossing the joints between the precast members.