ASAC Review NSLS II

1
ASAC Review - NSLS II
Nick Simos, PhD, PE NSLS II Vibration Analysis
July 17, 2008
2
OBJECTIVES

• Quantification of natural vibration environment
  at NSLS II site
• Qualitative and Quantitative assessment of
  cultural vibration
• Design optimization to adhere to specified
  Stability Criter

3
Focus Areas

• Natural Environment
• Cultural Noise
• Ring and experimental floor slab thickness
  optimization
• Column Footing/Ring Slab Interface Optimization
• Service Building Location-Orientation-Interface
  Optimization
• RF Compressor Building Location Optimization
  Cultural Noise Quantification
• Thermal Stability Analysis

4
Overview

• GOAL
• Taking into consideration the natural conditions
  at the NSLS II site and the anticipated cultural
  vibration as a result of the operation ENSURE
  that the stability criteria set for the ring can
  be met
• Approach
• Achieve the goal by relying on (a) the extensive
  array of measurements made at similar facilities
  as well as the NSLS II site and (b) the use of
  benchmarked computational models developed
  specifically to treat the vibration of NSLS II

5
NSLS II Ring Floor Baseline Criteria
Shown are MEASURED data at NSLS II site without
the filtering effect of the structure
6
NSLS II Site Conditions
Time lag s
7
NSLS II Site vs. Light Sources
8
Challenge
Given the existing conditions at the NSLS II site
and the anticipated cultural noise from facility
operations, can vibration levels on the ring
floor be established and what are the facility
design structural implications?
(a) Natural Environment Filtering
(b) Cultural noise/structure interaction
?
9
Benchmarking of Computational Model used in NSLS
II Vibration Analysis BNL Site Specific Field
Test
10
Benchmarking of Computational Model used in NSLS
II Vibration Analysis
11
Quantification of Ring Vibration due to Natural
Ground Motion Structure Filtering Effect
12
Quantification of Ring Vibration due to Natural
Ground Motion Structure Filtering Effect
13
Cultural Vibration Considerations

• SOURCES
• NSLS II Operating Systems (pumps, compressors,
  AHUs)
• External Events (wind)
• How is overall design affected?
• Role of ring slab and thickness (?optimization)
• Interface/interaction of superstructure with NSLS
  II ring (column footing/ring interface)
• Design optimization for support structures
  containing operating systems/sources (i.e.
  service buildings, RF compressor building, etc.)
• What is the INTEGRATED effect?
• What did we learn from other operating facilities?

14
CULTURAL Vibration Quantificationeffect of slab
thickness on floor vibration levels
Sources are ACTUAL measurements of similar
systems (pumps, AHUs, compressors) expected to be
operating on the NSLSL II Service Buildings
15
Service Building Design Optimization

• Objectives
• MINIMIZE the transmission of cultural vibration
  generated by AHUs, pumps etc. to be housed on the
  SB floor
• Explore and identify optimal location (inner or
  outer ring)
• IDENTIFY the interface conditions (SB with
  supporting soil and SB with Ring structure) with
  the minimal vibration transmissibility
• Establish guidelines for system layout

16
Service Building Design Optimization

• Approach and Resolution
• Establishment of a large database of similar
  system vibration levels from other facilities
  (measurements)
• Extensive analysis integrated with data
  validation
• Comprehensive Effort led to the adoption of the
  elevated, sectioned Service Building slab
  which, combined with the utilization of the free
  span between supports for system layout,
  MINIMIZES vibration transmissibility

17
Ring Slab Thickness Optimization
18
RF Compressor - Ring Interface
19
Effect of NSLS II site profile on cultural noise
transmission
20
Ring-Superstructure Interface
Optimization of both the LAYOUT and the distance
separating the ring slab bottom from the column
footing OPTIONS explored 20 36 72 and
0 IDENTIFIED as baseline design the 20 depth
separation option
21
Ring-Superstructure Interface
22
Column Footing/Ring Floor Interface Options -
Analysis
23
Assessment of Wind Gust Effect on Ring Floor 50
MPH used as Upper Operational Limit
24
INTEGRATED NSLS II Vibration Stability Cultural
Vibration from Multitude of Sources
?
25
Cultural Noise IntegrationHOW DO NOISE SOURCES
COMBINE ON NSLS II Ring Floor?
26
Ring Floor Girder/Magnet Interface

• Objective
• Using actual measurements at NSLS1, understand
  the dynamic coupling between the vibrating
  floor and the lattice

27
Lattice Displacement Response Spatial
Variation(on-going)
Objective Correlate the spatial/temporal
variation of the floor motion with lattice
misalignment and beam jitter
transfer function between free-field and ring
transfer function between ring and lattice
Utilize the power spectra characterizing the
stochastic, stationary nature of the free-field
ground motion (measurable) and via the
comprehensive model (ground-ring-lattice) that
can deduce the transfer functions obtain the
cross-spectra and the variance of misalignment
over the lattice
Time lag s
28
Thermal Analyses

• Objectives
• BERM effectiveness in minimizing temperature
  variations in tunnel
• Experimental floor temperature variation ? effect
  on ring thermal stability
• Integrated analysis of thermal stability
  (on-going)
• lattice thermal load/tunnel air heat transfer
• ring heat load removal

29
Ring Tunnel Thermal Analyses
30
SUMMARY PATH FORWARD

• The comprehensive vibration stability effort for
  NSLS II has helped in reaching design decisions
  in the following
• Ring and experimental floor thickness
  optimization
• Superstructure column/ring interface design
• Service and compressor building design and
  interface
• Further, through continuing measurements at the
  site and other LS facilities
• Ensured that the site and the NSLS II design meet
  the stringent criteria of vibration stability
• Validated methods for quantifying effects from
  multiple sources
• Moving forward
• OPTIMIZE operating system layout (cultural noise
  sources)
• OPTIMIZE interfaces and QUANTIFY effect of the
  major systems on ring floor
• Quantify the dynamic coupling between lattice and
  ring floor