Have you ever wondered how loads are distributed beneath a bleacher wheel, or what the maximum pressure generated by a bleacher wheel is? Well chances are that if you have been in the sports flooring industry you wonder about this quite a bit and fairly often.This is a summary of a research project where ASET helped a client examine exactly how their surface reacted to bleacher wheel loads and what pressures were generated by those loads.
In the fall of 2012, ASET Services Inc was contacted with an intriguing project involving allowable bleacher load levels. The first step in the project was to construct a test station capable of applying loads that represent individual wheels as well as the sets of wheels typically used in bleacher sets. The figure to the left shows this loading station. It allows us to generate loads that represent individual wheels as well as to simulate loads that would be transmitted to the ‘sets’ of wheels traditionally used in bleachers. This loading station was the first portion of the project. A series of tests were performed in the lab to collect deflection and indentation data for multiple load levels.
Using a variety of sensors and analysis tools, we were able to generate pressure contours for each wheel within the bleacher set and determine the maximum pressure generated by each wheel. The image to the right shows the raw pressure contours generated by two of the wheels within the set. It shows that there is an obvious difference in the area loaded by individual wheels. Further analysis would show there was also a significant variation in the maximum pressure generated by each wheel. We’ve added an image showing the digitized pressure contours collected during testing. It showed that the pressure increased rapidly at the perimeter of the wheel/surface contact area.
Using this information from the lab we were able to take our measurement system to the field and measure the actual pressures generated by the bleachers on site. We were able to work with the client to measure the pressures generated under a variety of different conditions with live load situations. The photo on the left shows a live load situation used to generate the kinds of pressures that would be expected during the use of these bleachers. One note, the photo has been purposely blurred to obscure the faces of the students involved in this study.
This project is just another example of how ASET Services responds to the unique and often non-standardized testing needs of our clients.