Abstract :
The rigid-plastic yield-line analysis of orthotropically reinforced concrete slabs under
uniformly distributed loading is developed as the lower-bound form of a linear programming
formulation. The analysis is extended to consider geometric variation of chosen yield-line patterns
by the technique of sequential linear programming. It is shown that the omission, within the
iterations of the sequential linear programming process, of the effects of geometric variation on
yield-line ultimate moments of resistance leads to a formulation which is, at best, inefficient, and
can be divergent or converge to an erroneous solution. Accordingly, a formulation is developed
which includes a linearized representation of the geometric sensitivities of the resistance moments
within the iteration process. This formulation is shown to be both effective and efficient for the
yield-line analysis of a number of example slabs which include a range of support conditions and
boundary geometries.
