Mr H. B. Gould (F) G. Maunsell & Partners): It has been a great privilege to hear the authors of three such interesting papers present them so interestingly. The fields they cover have such wide implications that it is difficult to know not so much where to ask questions but where to finish. I will limit myself, therefore, to one or two addressed to the authors of each of the papers.
The following is the text of the address given by the President, Professor Happold, at celebrations to mark the centenary of the Canadian Society for Civil Engineering held in Montreal in May. The commemorative medal presented to the Society was illustrated in last month’s issue of The Structural Engineer (p221). It is said that, when the first French settlers sailed up the St. Lawrence River, they were so appalled by the wildness of the country they saw that they wrote across the map ’Acanada’-here is nothing. Yet, we have come to learn that this nation has great resources and its development by man was- and is - inevitable.
After 50 years’ exposure to the atmosphere, much of the protective original patina on the figure of Lord Carson and on four panels set into a supporting granite column had fallen victim to bronze corrosion. Radiographic and microscopic tests were conducted to ascertain the physical structure of the statue and the condition of the metal. Superficial salts were gently cleaned off with very low pressure compressed-air containing fine glass ‘bead’ particles, a technique known as ‘microblasting’. After treatment with corrosion inhibitor, the metal was spray-coated with a durable clear lacquer developed especially for outdoor bronze to stabilise and protect it against moisture and dirt. To prolong its own effective life the lacquer received a mineral wax coating. Metallic salts from the corroding figure had not discoloured the non- porous granite comprising the remainder of the monument, and therefore stonework was not brought into the present conservation programme. M.F. Fry Research-based studies on the subject of protecting
BS5400 is a limit state Code, but it still specifies maximum Stresses under service load. This amounts to specifuing maximum allowable working stresses. The need for this restriction has been questioned on the grounds that stresses are not fundamental design criteria. The limits do, however, serve a useful function within the Code. The new revision to the Code allows the stress check to be avoided, provided certain rules are complied with. These rules have a logical bask and produce designs for simple beams which do not depart significantly from the stress limits themselves. One effect of the stress limits that has not been widely appreciated is that they produce a severe restriction on the economic advantage that can be obtained from the use of inelastic analysis at the ultimate limit state. This is because the service stresses, rather than ultimate strength, are critical in design, a fact that should be reflected in the attention that design service loads receive when loading is reviewed. P.A. Jackson