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ASAC Review - NSLS II

ASAC Review - NSLS II. Nick Simos, PhD, PE NSLS II Vibration Analysis July 17, 2008. 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.

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ASAC Review - NSLS II

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  1. ASAC Review - NSLS II Nick Simos, PhD, PE NSLS IIVibration 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 MotionStructure Filtering Effect

  12. Quantification of Ring Vibration due to Natural Ground MotionStructure 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 StabilityCultural 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

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