Dynamic response of racetrack surfaces

One of the most significant challenges in the operation of a horseracing venue is the maintenance of a consistent, safe and fair racetrack surface. The horse trainers, jockeys, owners, track superintendents, and the betting public depend on a properly maintained track for the success of this sport. Tens of millions of dollars are at stake on any given day, not to mention the lives of the horse and jockey. However, the track condition is appraised in vague and qualitative terms such as "fast and hard" or "wet." This vague nomenclature can be very misleading, since track material properties will make a huge difference on how a track responds to the loading of a horse's hoof under race conditions. Therefore, a quantitative means is desirable to evaluate racetrack condition. The soil loading conditions for horse racing are extreme with 9 kN of force applied at a rate of 10 m/s. Moisture content, sand and clay composition, organic material content, and tillage are traditionally the factors that are controlled in order to maintain a consistent track. The work described in this paper has focused on developing a tool that replicates the dynamics of a portion of the gait of a horse running on the track. A system has been developed that replicates the strain rate and loads applied by the hoof to the soil. By replicating the strain rate and load in a system, it is possible to measure the peak loads which occur in the hoof at the high strain rates encountered in horse racing. The system is currently being tested to provide quantitative base line data from tracks around the country. Data from this system will eventually be available to assist superintendents in maintaining the control of the track surfaces regardless of weather and other external factors.