The Irnpact of Structural Iron in France

Foundations of buildings near trees The above topic, raised in our column for 21 November last year and aired again in January and March this year, has attracted further comment from Mr Z. Przygoda, in Don Mills, Ontario, Canada: I have read with interest the many comments about trees and how they affect the foundations of buildings. This is an important part of structural design. Verulam

A timber bridge guardrail specimen, subjected to static loads, was mathematically modelled as a beam on coupled, elastic supports. The spring coupling was provided by the bridge deck structure to which the line of guardrail posts was attached. The spring stiffnesses used as input to the model were determined experimentally by transversely loading each post of a timber guardrail section of a longitudinal laminated deck bridge after the guardrail member was removed. Using these stiffnesses, the model was executed to predict the deflections of the reassembled guardrail system. The model proved to be a good predictor of both rail-displaced shape and magnitude of deflection. Superiority of the coupled spring model over a similar model assuming independence (uncoupled springs) of posts in the system was demonstrated. P.J. Pellicane, Professor R.M. Gutkowski and M.S. Malone

Mr A. N. Beal (M) (Thomason Partnership) There is a strong need to develop buckling analyses for columns of non-linear materials - not only for the hot-rolled stainless steel considered in the paper but also for reinforced concrete, plain concrete, timber, and masonry.