Issue 8

When a thin steel plate with flat stiffeners is loaded either axially or in bending it will eventually undergo large deformations in either Mode I or Mode II, where for Mode I the free edges of the stiffeners have only tensile stresses and for Mode II these stresses are predominantly compressive. Thus Mode I is a plate buckle whereas Mode II is a stiffener buckle. Associated with each mode is a plastic mechanism the load-deflexion curve of which defines a panel’s post-buckling behaviour. These mechanisms are analysed theoretically and then a study is made of the effects of each parameter. Laboratory tests on large stiffened panels are briefly described. N.W. Murray

Dr. W. B. Cranston : Professor Hendry has presented a large body of evidence related to clay brick masonry. The problem of lateral strength is relevant also to concrete block masonry. I should like to introduce work on this aspect carried out by the National Bureau of Standards in America, and also to mention work currently in progress at the Cement and Concrete Association.

All members when applying for admission to the Institution sign a declaration that they will be bound by the provisions of the Charter and Bye-Laws and by the Rules of Conduct. For the majority, the latter simply strengthen the duty that they in any case owe to themselves as professional engineers. For some members in their day to day work, however, the Rules call for the observance of long-standing conventions, ignorance or disregard of which places the professional reputation of a member at risk as well as reflecting adversely upon the Institution itself.

Tests were carried out on 24 lightweight concrete deep beams to study the effects of web openings on strength and cracking. The results of the investigation, studied in the light of previous investigations on deep beams without openings, have led to some conclusions which are useful in the design of deep beams where openings have to be provided for services or for access. A method of analysis is proposed, which complements that previously given in The Structural Engineer (October 1972) for deep beams without openings. F.K. Kong and G.R. Sharp