Abstract
The ultimate strength of the beam on the elasto plastic foundation, e.g. on the soil bed, is not yet clarified, but it seems to be quite necessary to investigate the collapse load of such beam to obtain the reasonable factor of safety in practical design. To pursue the process of fracture of a beam laid on the soil bed, it will previously be required to know the properties of the bed, and then the elasto plastic behaviours of the beam on this bed may be investigated. But the mechanical properties of the soil bed are so complicated that it is very difficult to solve the above problem exactly. In this paper, as an approach to the solution of this problem, the author attemped at first to idealize the mechanical properties of the foundation, and then discussed theoretically the elasto plastic behaviours of the long beam on this foundation. In results, he recognized that the behaviours of the above beam are conveniently related by a dimensionless parameterγ^^-.
