2.4.5 Demand on Diaphragms
The deflection in the plane of the diaphragm shall not exceed the permissible deflection of the attached elements as determined by the evaluator. Permissible deflection permits the attached element to maintain its structural integrity under the individual loading and continue to support the prescribed loads without endangering the occupants of the building.
Floor and roof diaphragms shall be designed to resist a minimum force equal to 0.5AV times the weight of the diaphragm and other elements attached to the building plus the portion of the seismic shear force at that level, (Vx), required to be transferred to the components of the vertical seismic-resisting system because of offsets or changes in stiffness of the vertical components above and below the diaphragm.
Diaphragms shall provide for both the shear and bending stresses resulting from these forces. Diaphragms shall have ties or struts to distribute the wall anchorage forces into the diaphragm as prescribed in Section 3.6.4 of the 1994 NEHRP Recommended Provisions.