This meeting is organised by the Wind Engineering Society and chaired by John Kilpatrick. The speaker is Andrew Allsop from Arup.
The discussion and workshop aims to explore in an accessible way the differences between time-history and the more common gust factor and frequency-domain methods for providing wind loads on complex roof structures.
The presentation is based on a number of different roof structures for which linear time-domain analysis was found to give a more realistic sense of the roof behaviour and, in some cases, indicates very different behaviour compared to some classic assumptions in common use.
In the early years of wind engineering, developing rapidly only from the latter half of the 1960s, our ability to measure and process data from large number of pressure taps was severely curtailed by the cost of computing. Time- and computing-efficient frequency domain methods were developed based on assumptions of static and dynamic behaviour which don’t always hold well for major structures we are designing today.
One example is that dynamic loads are distributed according to mass and mode-shapes, whereas direct wind loads are distributed according to area and the nature of the wind fluctuations. With the current computing power of even laptop computers, what’s preventing us working in the time domain more regularly?
Andrew Allsop is a Fellow of the UK Wind Engineering Society and a Director and Arup’s leading wind engineer based in London.