The Day the Earth Shook: Controlling Construction-Induced Vibrations In Sensitive Occupancies

Michael Wesolowsky, Swallow Acoustic Consultants Ltd. / Thornton Tomasetti

Floor motions can disturb occupants, leading to frequent complaints and loss of functionality. In laboratory and research facilities, this issue can be more critical, as high-resolution imaging equipment with stringent vibration criteria is often employed. As existing laboratory and research infrastructure ages, extensive renovations and additions to functioning facilities are being planned, designed and constructed. In many cases, these largely invasive projects are occurring while the existing vibration-sensitive facilities remain in operation. The control of construction-related vibrations form an increasingly important component of the planning, design and construction process for these situations.

This presentation provides three case studies of existing laboratory and research facilities which are undergoing extensive renovations and additions. In all three cases, the diagnostic imaging (DI) suites, containing Magnetic Resonance Imaging (MRI), Nuclear Magnetic Resonance (NMR) and Computed Tomography (CT) equipment, are located directly adjacent the additions. One of the facilities also contains a vivarium for primate and rodent research.

For all three cases, a series of vibration tests are described that were conducted using combination of backhoes, a caisson driller and a vibratory compactor to determine the extent of mitigation and monitoring required during the construction process in order allow the units to remain in operation. Further commentary is provided regarding the practical realism of vibration criteria for DI equipment, as it was found for more than one of the cases that the manufacturer-provided vibration criteria for the research equipment was being exceeded on a continuous basis, without any apparent loss of performance.

This approach of performing a series of tests and developing mitigation plans can allow laboratory and research facility owners to sustain operation during the most invasive renovations and additions to their facilities.

Learning Objectives

  • Understand how vibration criteria for sensitive laboratory and research equipment can often drive the design and operation of laboratory buildings;
  • Identify where a construction vibration assessment is necessary to ensure sustainable operation of an existing laboratory building;
  • Understand the cost and operational implications of renovations and additions to laboratory and research facilities; and
  • Learn where manufacturer-provided vibration specifications may potentially be treated with some skepticism as they may not represent the actual vibration limit required for successful operation of the sensitive equipment.

Biography:

A senior member of Thornton Tomasetti's acoustics, noise and vibration control engineering team, Dr. Wesolowsky has more than 20 years of experience in analysis, project management and design. Mike specializes in such areas as vibration studies for architectural and structural design, dynamic data acquisition and analysis, architectural acoustic studies and vibration control research and development. Mike joined Thornton Tomasetti in 2017 through its acquisition of Swallow Acoustic Consultants.

 

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