Since the identification, in the UK, of the need for further information on the dynamic loading of grandstands in the early 1990s, a number of research projects have investigated the issues relating to dynamic loading of structures due to groups of people participating in synchronised activities. These studies have, to date, largely focused on producing load models to accurately represent the dynamic crowd load and the human-structure interaction. However, whilst the vibrational response of grandstand structures is becoming better understood, the question arises as to what level of dynamic response is acceptable to the users. Currently there is very little experimental data available regarding human perception of vibrations in such crowd loading situations. As a result those producing design standards and design guides have very little information on which to base serviceability requirements. To address this, tests have been carried out at the University of Bath using a section of grandstand, whose dynamic properties could be varied, with the aim of developing acceptability criteria. Groups of participants were subjected to a range of vibrations induced by selected members of the group jumping in synchrony. Both those seated and jumping during the tests were asked to rate their perception and emotion of each vibration as well as the acceptability of the vibration in a real grandstand situation. These ratings were then used to statistically model perception and emotion to find the key vibration characteristics influencing the human response of both the seated and jumping participants prior to developing acceptability curves for each group. It was found that those seated are more sensitive to vibrations than those jumping tocreate them. The response of the jumpers is relatively simple and can be fairlyaccurately modelled using just a single variable namely the square of vertical RMSdisplacement. The seated response is much more complex but can be relativelyaccurately represented using logarithm of vertical RMS acceleration. The proposed acceptability criteria and load model generally tie in well withpreviously published guidelines provided that the serviceability criteria are in thesame format as the original research upon which they were based (i.e. peakaccelerations).
|Date of Award||31 Oct 2011|
|Supervisor||Antony Darby (Supervisor) & Ian Walker (Supervisor)|
- human perception
- crowd loading
- structural design