The basic flexural strength calculations for Coupling Beams are conducted in the same manner as for Section Cuts. Axial-flexural capacity and the resulting interaction ratio are calculated according to Section 7.6 of this manual.

Chapter 21 flexural checks are performed if the design criteria specify a Special Reinforced Concrete Wall system. In this case, the limitations placed on reinforcing ratio and positive/negative flexural strength required by ACI sections 21.5.2.1 and 21.5.2.2 are enforced. Design failure messages will be presented in the Design Warnings tab of the View/Update dialog if they are not satisfied. For the provisions of ACI section 21.5.2.2, the flexural strength is evaluated assuming zero axial load exists at the cross section.