All diaphragms with spans greater than 24 feet have plywood or diagonal sheathing. Structures in Building Type 2 may have rod-braced systems.
For conforming buildings, the evaluator may consider this condition as mitigated, and no calculations are necessary. The deficiency is in the strength and stiffness of the diaphragm. Evaluate the diaphragm stresses using the procedure given in Chapter 9 of the 1994 NEHRP Recommended Provisions. Also evaluate the deflections. A maximum displacement of 3 inches shall be acceptable. For horizontal bracing systems, see Section 7.5.