Chapter 40 The Day the Earth Shook: Controlling Construction-Induced Vibrations in Sensitive Occupancies Michael J. Wesolowsky, Melissa W.Y. Wong, Todd A. Busch, and John C. Swallow Abstract Floor motions can disturb occupants, leading to frequent complaints and loss of functionality. In healthcare facilities, this issue can be more critical, as high-resolution imaging equipment with stringent vibration criteria are often employed. As existing healthcare infrastructure ages, extensive renovations and additions to functioning facilities are commonly 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 processes for these situations. This paper provides two case studies of existing hospitals which are undergoing extensive additions. In both cases, the diagnostic imaging (DI) suites, containing Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) equipment, are located directly adjacent the facility additions. For both cases, a series of vibration tests are described that were conducted using a combination of backhoes, excavators, caisson drillers and vibratory compactors to determine the extent of mitigation and monitoring required during the construction process in order to allow the DI equipment to remain in operation. Further commentary is provided regarding the practical realism of vibration criteria for DI equipment, as it was found for one of the cases discussed below that the manufacturer-provided vibration criteria for a CT scanner were apparently inaccurate since construction activity generated vibrations that exceeded the constraints of those criteria without any subjectively apparent loss of performance. Keywords Vibration sensitive equipment • Construction vibration • Vibration measurements • Vibration mitigation • Model validation 40.1 Introduction Over the years, many existing healthcare facilities have required extensive additions and renovations to accommodate new facility demands and technology. Often, these renovations occur while the existing healthcare facilities remain in operation with associated concerns over construction vibration. Healthcare facilities often contain highly vibration-sensitive equipment whose accuracy in operation could be compromised as a result of the construction-induced vibration. As such, the control of construction-related vibrations forms an increasingly important component of the planning, design and construction process for these projects. Two case studies are presented in this paper that describe the different vibration testing methods as conducted at two hospitals that are, as of the publication of this paper, undergoing extensive facility additions. Both hospitals required that the Diagnostic Imaging (DI) equipment, which has stringent vibration requirements, remain in operation throughout the construction process. The first case study describes vibration testing that included the simulation of construction activity using a variety of construction equipment, in order to determine construction vibration zones of influence for the entire hospital. The second case study describes both simulated construction-vibration testing along with real-time continuous vibration monitoring during the actual construction stage. M.J. Wesolowsky ( ) • M.W.Y. Wong • J.C. Swallow Swallow Acoustic Consultants Ltd., Thornton Tomasetti, 23-366 Revus Ave., Mississauga, ON, Canada, L5G 4S5 e-mail: mwesolowsky@swallowacoustic.ca T.A. Busch Pinchin Ltd., 2470 Milltower Court, Mississauga, ON, Canada, L5N 7W5 © The Society for Experimental Mechanics, Inc. 2017 J. Caicedo, S. Pakzad (eds.), Dynamics of Civil Structures, Volume 2, Conference Proceedings of the Society for Experimental Mechanics Series, DOI 10.1007/978-3-319-54777-0_40 321
RkJQdWJsaXNoZXIy MTMzNzEzMQ==