A design strip is an object that:

• contains a series of cross sections at specific locations
• is usually the length of a span, or part of a span, but can in fact have any length within the structure
• integrates resultants (moments, shears, axial forces, torsions) for all load combinations along each cross section (and, hence, across the design strip’s width)
• applies appropriate code rules to the resultants

A design strip is the same as a span segment strip.