I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
The Day the Earth Shook: Controlling Construction-Induced Vibrations in Sensitive Occupancies
Presented by:
Michael J. Wesolowsky, Ph.D., P.Eng.Associate Principal
Swallow Acoustic Consultants Ltd. /
Thornton Tomasetti
366 Revus Ave., Unit 23 Mississauga, ON, Canada, L5G [email protected]
I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
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.
The Day the Earth Shook: Controlling Construction-Induced Vibrations in Sensitive Occupancies
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
Case Study #1
Introduction Vibration Criteria
Case Study #2 Case Study #3
Summary
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
So What’s the Story?
• Our firm has been involved in several projects over the years which involve the control of construction-induced vibrations
• Many are straightforward, based on municipal regulation• And best practice
• With increasingly vibration-sensitive equipment:• Often difficult to obtain vibration criteria• Often difficult to predict source levels
• How do we develop a plan to address these issues?
Introduction
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
How do we Define Vibration Criteria (VC)?• Traditionally, over the past 25 years vibration criteria for sensitive equipment was
given as the so-called ‘VC-Curves’ • Vibration Criteria Curves
• Provide frequency-dependent root mean square (rms) levels of velocity, grouped in 1/3 octave bands
Vibration Criteria
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
VC-Criteria
Imperceptible
Perceptible
Vibration Criteria
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
Vibration Criteria
Curve
Max Velocity
Amplitude1
mm/s (min/s)
Description of Use
Achievable
Magnification
Factor2
Workshop (ISO) 800 (32,000) Distinctly perceptible vibration. Appropriate to workshops and non-sensitive areas -
Office (ISO) 400 (16,000) Perceptible vibration. Appropriate to offices and non-sensitive areas. -
Residential Day (ISO) 200 (8,000)Barely perceptible vibration. Maximum recommended for general sleep areas. Usually adequate
for computer equipment.40x
Residential Night (ISO) 140 (5,600) Appropriate for most sleep areas such as hospital recovery rooms. -
Operating Theatre (ISO) 100 (4,000)Threshold of perceptible vibration. Suitable in most instances for surgical suites, catheterization
procedures, and for other equipment of low sensitivity. Suitable for very sensitive sleep areas.100x
VC-A 50 (2,000)Adequate in most instances for microbalances and optical balances. Also suitable for most
vivaria.400x
VC-B 25 (1,000) Micro-surgery, eye surgery and neurosurgery, CT, CAT, PET, fMRI, SPECT, DOT, EROS. 750x
VC-C 12.5 (500)Appropriate for many MRIs, NMRs, and moderately sensitive electron microscopes to 1 mm detail
size.1000x
VC-D 6.25 (250)Suitable in most instances for demanding equipment, many MRIs, electron microscopes (SEMs
and TEMs) to 0.3 mm, and E-Beam systems.30,000x
VC-E 3.12 (125)
A challenging criterion to achieve. Assumed to be adequate for the most demanding of sensitive
systems including long path, laser-based, small target systems, systems working at nanometer
scales and other systems requiring extraordinary dynamic stability.
-
VC-F 1.56 (62.5)Appropriate for extremely quiet research spaces. Generally difficult to achieve in most instances.
Not recommended for use as a design criterion, only for evaluation.-
VC-G 0.78 (31.3)Appropriate for extremely quiet research spaces. Generally difficult to achieve in most instances.
Not recommended for use as a design criterion, only for evaluation.-
Notes: 1. As measured in one-third octave bands of frequency over the frequency range 8 to 80 Hz (Workshop through VC-B), or
1 to 80 Hz (VC-C through VC-G).
2. Approximate magnification factor achievable for optical microscopes.
Vibration Criteria
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
However…• In the past few years, imaging equipment has been improving
• higher resolution = higher vibration sensitivity
• Generic VC-Criteria provides a GENERAL design guideline, but is no longer considered absolute
• It is common for manufacturers to provide their own criteria• often require proof of performance investigation
Vibration Criteria
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
Existing Hospital in Toronto• Original 110-bed patient tower constructed in 1929• New addition / building built approximately every decade since
• Frankenstein Hospital!• Major 550,000 sf redevelopment announced:
• Replacement of the oldest beds • Replacement of the mental health inpatient units• Consolidation of ambulatory care and ambulatory procedures• Creation of two levels of underground parking and a new main entrance• Accommodation of other administrative and support services needed to support the
clinical services
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Construction Vibration
I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
So What’s the Problem?• The construction will be phased over several years• Existing hospital operations cannot be compromised• Several sensitive adjacencies to the construction site
• Operating Suites• Diagnostic Imaging• Laboratories
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Construction Vibration
I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
Operating Suites
Diagnostic Imaging
First to be Demolished
Laboratories
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Construction Vibration
I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
So What do We do About it?
• SACL hired directly by hospital to conduct an initial series of tests• Backhoe used in the parking lot to determine vibration transfer to the DI areas
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Construction Vibration
I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
Criterion
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Construction Vibration
What we Found
I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
What we Found
Criterion
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Construction Vibration
I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
What we Found
Criterion
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Construction Vibration
I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
What we Found
Criterion
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Construction Vibration
I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
And how did the Hospital React?• Mass panic• Commissioned a larger scale testing scheme to determine building response to a wide
range of construction activities:• Excavator• Caisson Driller• Vibratory Compactor
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Construction Vibration
I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
Data Analysis• Based on the measured source levels and site-specific attenuation, we estimated the
expected vibration caused by:• Phase 1: Demolition of the E Wing and F Podium• Phase 2: Construction of the new tower• Phase 3: Renovation of the F and D wings• Phase 4: Demolition of the A, B, C, D podium and F wings
• Developed “Zones of Influence” throughout the site due to each activity
• FEM models of the building were also used to determine expected attenuation
Construction Vibration
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
As a Result…• Specifications were developed so that design/construction team could properly bid
on/cost the project• Consideration has been given for moving DI to temporary area
Construction Vibration
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
Existing Hospital in Southwestern Ontario, Canada• Original hospital constructed in the 1950s• On the northwest corner of the current location, they are building a three storey tower
to house:• A new Emergency Department• Surgical Suites• Medical Devices Reprocessing Department• Permanent home for the Mental Health and Addiction Services Unit
Construction Vibration
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
So What’s the Problem?• The construction will be directly adjacent to the existing diagnostic imaging and nuclear
camera suites• Underpinning directly under the CT room
Construction Vibration
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
Addition
CT Scanner Nuclear Cameras
Construction Vibration
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
So What do We do About it?• SACL hired to conduct a series of tests
• Backhoe used in the parking lot to determine vibration transfer to the DI area
Construction Vibration
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
Background Vibrations
Criterion
Construction Vibration
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
Backhoe-Induced Vibrations
Criterion
Construction Vibration
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
And Then What?• Specifications were developed so that the construction team could properly bid on/cost
the project• Procured mobile CT in a trailer during main construction
• At a cost of $500,000!
• Monitoring plan developed to determine the vibrations in the original DI area• Intention was to operate CT scanner in original location once vibrations were
considered acceptable
• BUT…
Construction Vibration
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
And Then What?• Measurements showed consistent and excessive exceedance of criterion
Construction Vibration
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
Typical Weeks of Monitoring
Construction Vibration
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
Liability Disaster?• Hospital test-operated the existing CT scanner during construction, and found NO issues
with imaging quality• After 7 months of monitoring, program discontinued, mobile CT removed, full operation
of existing CT scanner resumed• Over our objections!
• Are the manufacturer criteria significantly over-conservative?
Construction Vibration
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
• University hospital
• Renovation activities:
• Partition demolition
• Slab cutting
• Elevator installation
• Construction hoist
• Clinical laboratory and diagnostic imaging equipment
Biomerieux VITEK MS Mass Spectrometer
Construction Vibration
Existing Hospital in Chicago
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
PREDICTIVE VIBRATION CONTOUR MAPS
Construction Vibration
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
PREDICTIVE VIBRATION CONTOUR MAPS
Construction Vibration
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
Construction Vibration Control Methods
COMBINATION OF ALL OF THESE OPTIONS
EQUIPMENT RELOCATION
•ONLY FEASIBLE FOR SMALL EQUIPMENT
•COULD IMPACT WORKFLOW
ISOLATION TABLES/MOUNTS
•DEPENDENT ON EXCITATION FREQUENCIES
•MANUFACTURER RESTRICTIONS
ACTIVITY SCHEDULING
•ECONOMICAL
•FEASIBLE FOR SHORT TERM ACTIVITIES
DIFFERENT CONSTRUCTION
TECHNIQUE
•OPT FOR LESS DISRUPTIVE METHODS
Construction Vibration
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I2SL Annual ConferenceOctober 21-23, 2019
Denver, Colorado
1. Construction vibration can have significant impact on existing facilities with vibration-sensitive occupancies
2. Extensive vibration testing may be necessary to determine extent of “Zone of Influence” and possible mitigation measures
3. Monitoring is often necessary during construction to ensure safe operation of vibration-sensitive equipment
4. Are manufacturer vibration criteria realistic??
What Did We Learn?
Concluding Comments
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