Description

This session presents strain compatibility as a single, general procedure for calculating the ultimate flexural resistance of reinforced and prestressed concrete sections. Based on plane sections, material stress-strain curves and equilibrium, the same approach handles tendons distributed over the depth, composite sections and mixed concrete grades.

The method is explained step by step, with the neutral axis depth treated as the one unknown to be solved, along with practical convergence checks that make the calculation robust. It is then applied to a real, anonymised pre-tensioned beam with in-situ infill, assessed to the DMRB standards CS 454 and CS 455, covering both sagging and hogging resistance.

The final part sets out a verification protocol for MIDAS CIVIL NX: which inputs need to be aligned and which intermediate quantities should be compared before looking at the final MRd. Results are reconciled against a workbook and a third-party output, giving engineers a clear way to prove a software result from first principles. The session closes with a Q&A.