Vibration Perception and Comfort Levels for an Audience Occupying a Grandstand with Perceivable Motion

This paper reports a controlled laboratory investigation on the evolution of human vibrationperception and comfort states as a result of a change in the vibration levels of an occupied grandstand structure. Our structural dynamics laboratory is equipped with a fully instrumented real-life grandstand whose motion could be controlled to simulate a vibrating structure. Students were recruited to participate as a seated and a standing audience and to provide feedback on the state of their comfort and vibration perception during exposure to different vibration levels. After applying frequency weighting filters specified in different standards to each vibration level, charts are presented to describe vibration perception and comfort levels of the audience given a prescribed movement of the structure. The charts indicate that the perception variable takes on its extreme state sooner than the comfort variable, confirming that vibrations are felt long before they are generally deemed uncomfortable. This makes the assessment of human perception of vibrations to be of primary importance in establishing safety criteria. Finally, the results were compared with recommendations of several international standards and design guidelines in the same area of research. The results of the comparison showed serviceability data obtained from our grandstand study to be lying significantly below the recommended limits for transportation structures (BS6841) but significantly above the recommended limits for most classes of buildings (BS6472). This implies a serviceability limit state for grandstand-design lying somewhere between the recommended limits of the two standards. These results are an important contribution to the establishment of serviceability requirements for grandstand structures.