VIBRATION

Structure-borne noise and vibration are present in every building.  Mechanical equipment, typically related to a building’s HVAC system, is commonly the source of structure-borne noise and vibration.  Ideally, the control of these sources of vibration is achieved during the design of the mechanical system; however, there is regularly a need to address a vibration issue.  Metropolitan Acoustics offers clients the expertise to engineer solutions to vibration challenges.  Our capabilities include vibration measurement, analysis, monitoring, mitigation, and expert witness testimony, which offer our clients a one-stop shop for vibration consulting services.

Construction Noise and Vibration Monitoring

Building construction projects can last several weeks to several years. Depending on the nature of the project, building renovations and additions often disturb the building occupants and the occupants of nearby buildings.  Monitoring the construction noise and vibration is becoming an increasingly common means of establishing a baseline prior to construction, facilitating construction and relocation schedules, and finding solutions to noise and vibration challenges.

Using our state of the art equipment and proprietary software tools, Metropolitan Acoustics has the expertise to monitor construction site noise and vibration remotely.  Metropolitan Acoustics provides the complete system for short- or long-term projects of any size adapted to each client’s project requirements.

Micro-Vibration

To many, vibration and micro-vibration are thought of as one in the same.  However, there are very significant differences between these two fields of vibration, requiring expertise specific to each.  Metropolitan Acoustics has the tools, technologies, and expertise required to address all types of micro-vibration applications.  Sensitive laboratory equipment, susceptible to minute building vibrations is the most common micro-vibration application.  Examples include magnetic resonance imaging (MRI), computed tomography (CT) scans, and scanning transmission electron microscopes (STEM) to name a few. Metropolitan Acoustics offers continuous surveillance for days, weeks, months and years, if required, via our application-specific software and client cloud configurations.

Vibration Control for Research and Medical Centers

Metropolitan Acoustics offers Vibration Monitoring and Modeling to protect research facilities and vibration sensitive spaces (labs, MRI rooms, scan/imaging suites, microscopy rooms, animal research/holding rooms, behavioral testing suites, operating rooms, medical patient rooms, and exam rooms) from intruding vibrations. Our services include:FEA dynamic models 2

  • Pre-construction site vibration surveys.
  • Construction vibration monitoring and management.
  • Multi-point synchronized measurements with wireless tri-axial accelerometers.
  • Real-time cloud based data processing and alert system for short or long term surveillance.
  • Finite Element Analysis (FEA) modeling of base building structures.

Site Vibration Surveys

  • Pre-construction site vibration survey and measured time-history accelerations.
  • Ambient vibration testing.
  • Conformance measurements.
  • Diagnostics.

Construction Vibration Monitoring and Management

  • Monitoring within and throughout buildings during construction projects while occupied.
  • Adjacent buildings and properties during blasting, pile driving, soil compaction.
  • Wireless cloud-based data transmission system for long term monitoring (weeks to years).

Finite Element Analysis (FEA)FEA dynamic models 1

  • FEA modeling offers dynamic analysis of single bays, entire floors, and entire buildings. FEA modeling of structural dynamics allows the review of vibration transmission via columns, beams, slabs, facades, curtain walls, cantilevers, foundations, footings and pilings. Dynamic analysis can include modal analysis, modal time-history, power-spectral-density (PSD), Ritz and Eigen vectors and response spectrums.
  • Control of vibrations at the source where possible (external sources, internal activities, and service machinery)
  • Transmission path mitigation analysis. Integrate vibration isolation strategies during construction rather than as post-construction upgrades.
  • Structural resonance, mode shapes and amplitude peaks of bays, beams, girders and columns can be detected in the design stage.

Vibration sources in research and medical facilities include:

Slab modes

  • Renovations and construction.
  • Ground borne vibration propagation
    • Surface (pavement, soil), soil strata, bedrock.
    • Sources: pile driving, blasting, soil compacting, heavy vehicles and equipment.
  • Walking footfall on composite slabs.
  • MEP
    • HVAC mechanical rooms.
    • Penthouse rooftop units.
    • FPUs mounted within medical service spaces.
  • Major components of the life support system
    • Filters.
    • Pumps.
    • Biofilters.
  • Long-span girders, bays and cantilevers.
  • MRI machines.
  • Emergency generator and Co-gens.
  • Elevator machine rooms.
  • Helipads.
  • Wind loads on curtain walls and large windows.
  • Road and rail traffic, includes area bridges and tunnels.
  • Vehicle parking and tunnels sharing the base building structure.
  • Loading docks under or around the base building.
  • External machinery operating in the vicinity.

Medical Center sound and vibration specifications are part of LEED for Healthcare certification IEQc2, FGI Guidelines for Design and Construction of Healthcare Facilities (FGI Guidelines), Health Care Facilities (SV Guidelines).

  • Interior sound isolation and room noise.
  • Criteria for acoustical finishes and site exterior noise control.
  • Floor vibration limits for critical spaces.