Verulam

Brian Simpson will succeed Patrick Dowling as President of the Institution 1995-96 at an Ordinary Meeting at Institution headquarters on 5 October 1995. The handover will be at 6 pm when the new President will give his Presidential Address ‘Professional development’, the full text of which will be published in The Structural Engineer on 19 October.

Based on the concept of lumped masses and the established equivalent continuous approach for the analysis of coupled shear walls, a continuous-discrete approach for evaluating their natural frequencies is proposed in this paper. The coupled shear wall system is treated as a continuous system (i.e. where the discrete beams are replaced by an equivalent continuous medium) and a discrete system (or lumped mass system) at different stages of dynamic analysis. The advantages of the two types of analytical system are jointly utilised. The accuracy and eficiency of the methodology adopted in the continuous-discrete approach are verified by making comparisons with the precise classical approach and a couple of approximate approaches for evaluating the natural frequencies of typical coupled wall structures. The minimum number of lumped masses needed in the present approach to obtain an acceptably accurate value of natural frequency for any modal vibration of coupled shear walls is also discussed. In addition, a simple chart, based on the continuous and the continuous-discrete approaches, for estimating the fundamental frequencies of coupled shear walls is presented. A numerical example is given to show the application of the chart and the accuracy of the procedure in estimating the fundamental frequencies of coupled shear walls. Guo-Qiang Li and B.S. Choo

When I asked Patrick Dowling how he had found his presidential year he said, ‘the word that springs to mind is, exhilarating.’ John D. Allen