Analysis of deep beams with torsion
Because RAM Concept assumes that deep beams behave like slabs, RAM Concept will over-estimate the torsional stiffness of deep beams. At the worst case, RAM Concept ’s assumptions lead to a torsional stiffness at the deep beam that is proportional to bh3 , while the true torsional stiffness is proportional to b3h . Typically RAM Concept ’s overestimation is not that great as the slab elements have a transverse shear stiffness that makes the beams more flexible. The larger the number of elements across a deep beam, the smaller the overestimation of torsional stiffness.
The torsion in the beam may be necessary for a complete structural load path - for this reason it cannot be ignored. It may be appropriate to reduce the torsional stiffness of the beam (this will modify the structural load path to one that is less dependent upon the beam torsional capacity). Concept provides four options of considering this torsion in design. See "Torsion Considerations" for more information.