RECENT research in steel structures has demonstrated that the usual assumption of pin joints fails to predict with any approximation to accuracy the stresses in a framework, especially in the case of stanchions; and it is not too much to say that the publication of the Reports of the Steel Structures Research Committee shows that any further advance in design must depend upon the recognition of rigidity or semi-rigidity in the connections. Development of the mathematical analysis of the rigid frame has led to the conclusion that the exact solution to the problem is one of great complexity. So much so, that repeated attempts have been made to popularise the experimental or model methods of Professor Begg, in which a solution is obtained by measurements made on a small-scale celluloid model representing the ultimate frame. John Mason
IN reinforced concrete design it is common practice to assume that the composite material is both homogeneous and elastic. In the particular case of the reinforced concrete slab, for example, design is fundamentally dependent on the analysis of the homogeneous and elastic plate. In a few specific cases the theory of plate action has been solved mathematically but the solutions are unfortunately in the form of double infinite series and long and tedious calculations are necessary before the results can be applied to the actual design of the slab. In otber cases solutions by means of approximate methods have been put forward, some of which may not be wholly satisfactory. L.G. Simms