Issue 8

Many clients see engineers as a cost rather than delivering a benefit – a commodity that can be bought anywhere. Do we really know what is important to our clients? Are we addressing what clients believe to be the biggest risks to their business? Do we understand their approach to risk? To deliver a successful product or service requires that we practicing engineers manage all sorts of uncertainties to a beneficial outcome. We do it all the time, but few clients appreciate this. This paper aims, with examples, to help us add value for our clients and ourselves by improving the way we manage, and are seen to be managing, risk. Patrick S. Godfrey, FREng, FICE, FInstPet, BSc Business Solutions Director, Halcrow, London, UK

The results of 32 steel beam tests, with closely spaced lateral restraints, and associated mill and coupon tests provide an interesting insight into the additional moment capacity available due to strain hardening. Differences are identified in the yielding and strain hardening behaviour exhibited in the mill and coupon tests. While the mill tests generally provide a safe estimate of the yield stress, the coupon tests give a better measure of the strain hardening characteristics of the beams. A bi-linear moment–curvature relationship provides an accurate representation of the moment–rotation measurements in the beam tests. A simple model is proposed for predicting the critical flange strain at which interactive local and lateral buckling limit the maximum moment and associated curvature in the beam. Criteria are identified for utilising an additional 8% of moment capacity above the conventional plastic moment in the plastic design of beams. A. R. Kemp, BSc, MSc, PhD, FSAICE, MIStructE University of the Witwatersrand, Johannesburg, South Africa M. P. Byfield, BEng, PhD, MICE, CEng Royal Military College of Science, Cranfield University, Swindon D. A. Nethercot, BSc, PhD, DSc, FREng, FIStructE, FICE, CEng Imperial College of Science, Technology and Medicine, London