For this project, a confidential defense contractor commissioned Ross Group Engineering to complete the design of reaction mass systems for vibratory testing equipment at two separate locations. Both locations required the systems to be designed for installation in existing facilities and in close proximity to other equipment and building foundations. Additionally, each location demanded two reaction masses of approximately 310,000 pounds housed in a “bathtub” type of foundation to provide structural support and vibration isolation. Ross Group Engineering performed a dynamic analysis to ensure testing performance and select isolation materials that will minimize vibration transmitted to adjacent structures. This foundation type was used to prevent transmission to surrounding structures and sensitive equipment.