The Art of Structural Engineering. Discussion on the paper by Peter Dunican CEng MlStructE (Member o

In the past few years the first Ordinary Meeting of the New Year has been given over to a discussion or debate on a theme of topical interest to structural engineers. Against the background of the much-publicized structural collapses of 1966 the meeting on Thursday 12 January at 6 o’clock to debate the motion ‘ That structural design is best carried out in professional offices ’ will provide an opportunity for airing members’ views on these events.

Dr. Le-Wu Lu (Research Associate-Professor of Civil Engineering, Lehigh University, Bethlehem, Pennsylvania) writes:- 'The authors are to be congratulated for contributing an interesting paper in an area which has attracted considerable attention in recent years. The use of computers in elastic-plastic analysis provides not only the potential of dealing with highly complex structures but also the capability of inclusion of many so-called "secondary effects". The program developed in the paper has attempted to include almost all the major secondary effects, except, as the authors noted, the following two:- (l) the effect of reduction of plastic moment (2) the spread of plastic zones in the members.

The Craigellachie bridge, over the River Spey at Craigellachie, Banffshire, was originally designed and constructed in cast iron by Thomas Telford in 1814-15. It was reconstructed in 1963-64 to make it capable of carrying modern traffic not greater than 14 tons the bridge, it was essential to keep as much of the original character in weight. In addition, it was recognized that, in reconstructing as possible; when a new bridge is constructed nearby, the cast-iron bridge is to be restored to a condition which will enable it to be retained for as long as possible as a monument to Thomas Telford and his work. W.W. Lowson