Measuring Pedestrian-Induced Vibrations to Assess the Suitability of an Existing Laboratory for Vibration-Sensitive Equipment

Julia Graham, RWDI

Specialized laboratory equipment often requires low-vibration environments for proper functionality. On elevated floors, occupant footfalls are often the most critical source of vibration. When existing spaces are re-purposed to house sensitive equipment, there is an opportunity to conduct tests to quantify expected levels of pedestrian-induced vibration. A case study is presented discussing vibration issues encountered when an existing laboratory building at a university is renovated to house a new research group. This new group will be relocating vibration-sensitive microscopes from an existing CMU and concrete building to the newly renovated building.

There is a reluctance among some researchers to move vibration-sensitive equipment to the newly renovated building, because it was constructed using structural steel and composite deck and it is rumored to be vibration-prone. The University contracted for a vibration study to serve two purpose: 1) the levels of vibration at the existing and proposed microscope locations were quantified to assess the suitability of the new space; and 2) the overall vibration "health" of the newly renovated building was quantified in order to dispel rumors about its poor vibration performance. This presentation discusses pedestrian-induced measurement techniques, and issues surrounding the definition of vibration criteria and the perception of vibration. Results and lessons learned from the project are discussed and mitigation techniques, for spaces that fail to meet the required criteria are presented.

Learning Objectives

  • Understand how floor vibrations affect laboratories;
  • Understand how pedestrian-induced vibration is measured in existing buildings;
  • Understand equipment-specific vibration criteria; and
  • Understand how vibration can be mitigated.

Biographies:

Julia is a structural dynamics specialist who has delivered vibration control solutions for more than 70 building projects, including 20 hospitals and research centers. She works closely with architects and fellow engineers to design facilities that are comfortable for occupants and able to fulfill their intended functions--whether they are landmark residential towers or laboratories containing advanced vibration-sensitive imaging equipment.

 

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