Structures-The Impact of Modern Metallurgy Discussion on the Paper by Professor A. G. Quarrell, D.Sc

THIS paper deals with a class of arch known as the “Stabbogen.” The arch is loaded through the hangers which may be referred to as “wire-hangers” since they are assumed to be simple tension members having comparatively small flexural rigidity. The hangers are connected to a rigid chord at their lower ends, and thus become inclined when the arch rib deflects laterally. The load is considered to be applied by means of a horizontal thrust H at the ends of the rib instead of through the hangers. Chin Fung Kee

The two extremes of pressure to which a retaining (i) the active pressure of the soil on the back of a wall resulting from slight movement of the wall away from the filling, and (ii) the passive resistance of the soil on the front of a wall to slight displacement of the wall towards filling. J. Rygol

This month's letters discuss foundations in shrinkable ground and highlight a survey on structural optimisation in practice.