Approved Persons: Insurance Aspects

A happy New Year to you all! The Christmas holiday has proved inspirational to a number qf readers... Deflection of portals Mr D. H. Camilleri has written from Malta and is concerned about the vertical deflection of portal frames. He writes: I have often wondered regarding the validity of the ridge deflection dRE quoted in section 11.5 of Manual for the design of steelwork building structures given as: dRE = dE X cot e, where dE is the horizontal deflection.

There have been many situations in which flexural members - especially bridge girders -have been found to have less than the desired strength. A widely used method of providing additional strength has been the introduction of prestressing by means of external tendons'. External tendons are prestressing strands situated outside the original concrete section and are connected to the structure by anchorages and deviators. B.J. Sun

This paper considers where over-design may exist in current engineering practice and, in particulal; traces the history of imposed load allowances and the relevance of current values, as designated in the current British Standard, to today’s commercial ofice buildings. Independent research into actual loading conditions is considered and compared with the normally adopted values of imposed loads. Anomalies with other western European countries are noted, and areas where a review of the current relevant British Standards may be appropriate are identfied. J.A. Austin