This assumption is made due to its simplicity and conservative nature and is reasonable unless the tension steel strain is very close to 0.005 – the tension-controlled limit strain. The following algorithm assumes one layer of tension steel, that is, d t = d, the depth of the tension steel centroid. The program offers an option to account for these conditions by automatically computing beam support widths from Model Design Criteria under Concrete > Design Criteria.

For flexural design, the critical section at a support may be taken at the face of the support (but not greater than 0.175 * span length from the support center). The program designs each beam against positive or negative moment with single layer of tension steel with tension-controlled condition. Minimum reinforcement is computed for the bottom steel. The beam top and bottom flexural reinforcement is computed at each analysis station along the beam length. If axial force or biaxial bending actions cannot be neglected, the use of column design module is recommended. Furthermore, no deep beam action is considered. Axial force, bending about weak axis (local y), and torsion are not considered.

The concrete beam module designs concrete rectangular or Tee beams against enveloped bending about strong axis (local z) and enveloped shear along local y.