The comparative merits of hand and automated upper and lower bound techniques for the collapse load estimation of reinforced
concrete slabs are examined. Examples, drawn from both theoretical and practical design work, are used to show that both hand
and automated upper bound yield line techniques can produce significant, unsafe errors. Automated lower bound solutions, however,
are shown to consistently provide safe estimates that are not unduly conservative, provided appropriate formulations are adopted.
As long as the engineer is willing to dispense with the crutch of a yield line pattern, it is therefore contended that, whilst
Heraclitus may be correct in that both the upper and the lower bound roads can lead to one and the same collapse load, the
lower bound road gets you there, certainly more safely, and usually quicker, as the Traditional Song suggests.