Other calculations have looked at the analysis of beams where the steel stress
is within the elastic range, and the concrete stress is sufficiently
low that the assumption of linear elastic behaviour in compression is a
reasonable approximation. I now move on to analysis for the ultimate
limit state, where some or all of the steel is past its yield stress,
and the concrete compression zone may be analysed as having a constant
stress, close to its failure stress.
This file ULS Design Functions.zip contains
User Defined Functions (UDF’s) that will find the ultimate bending
capacity of any reinforced or prestressed concrete section (defined by
rectangular or trapezoidal layers) with any number of layers of
reinforcement, when subject to a specified axial load. As for the
elastic design functions, the analysis uses a closed form solution,
rather than an iterative procedure. The current version follows the
Australian Standards AS 3600 or AS 5100. Other codes will be added to
future versions. Details of the procedure will be given in later posts.
Screen shots:
Input, circular section
Output, circular section