The main (longitudinal) reinforcement is calculated for both sagging and hogging moments on the basis of the section profile and parameters defined in the Design Criteria menu. Compression reinforcement is provided where required.

The design of a beam is based on an envelope of design forces and thus at each of the defined sections, the program determines the required area of steel for both the maximum hogging moment and maximum sagging moment at that section.

The beam is then divided into sub-beams, that is, sets of spans which share the same dimensions and covers, and so may make use of the same basic reinforcement cage.

For each sub-beam, the sections that have the largest sagging and hogging moments are identified and the most efficient reinforcement is calculated for the range of bars specified in the Design Criteria. The program limits the design to 8 bars in any one layer and uses a maximum of 2 layers in each face.

The program then goes along the beam and checks each section to see how many bars from the critical sections can be removed. The bars are only removed if they are not required to resist bending in either direction, and provided that all spacing checks may still be satisfied.