Nonstructural Testing Research Needs to Support Performance Based Seismic Design

Transcription

1 Nonstructural Testing Research Needs to Support Performance Based Seismic Design Jeff Gatscher Fellow Engineer, Schneider Electric, USA 2 September 2010

2 Presentation Agenda Part 1 Nonstructural Systems Performance Based Seismic Design Part 2 Fragility Functions Sub-system Decomposition Part 3 Technical Implementation Research Needs 2

3 Part 1 Nonstructural Systems Nonstructural building systems include: Architectural Elements such as parapets, partitions, facades, cladding, glazing, lighting, etc Our Focus Mechanical and Electrical Equipment (also called components) like pumps, generators, air handlers, compressors, transformers, switchgear, emergency power supplies, etc. Mechanical and Electrical Distribution Systems such as process piping, fire sprinkler systems, HVAC ductwork, electrical busway, conduit, etc. Building Occupancy Contents bookcases, shelving, office equipment, etc. Nonstructural systems transform an empty skeleton into a functioning building 3

4 Part 1 Nonstructural Systems Essential Building Most often highly complex More ambiguous compared to building elements Qualification ownership not clearly defined More costly than the building (> 85% of total cost excluding land) Building function entirely dependent on nonstructural performance Essential Building Example CA Surgery Center 4

5 Part 1 Nonstructural System Elements Distribution Elements Equipment Elements Mechanical room Electrical room 5

6 Part 1 Large-class Nonstructural Category Weight > 6,000 kg Footprint > 50 m 2 Physically massive systems: Generator Sets Uninterruptible Power Supply Cooling Towers Industrial Chillers Elevator Systems... Cost > 250K Or, highly expensive systems: Semiconductor Fabrication Equipment Medical Radiation Treatment Equipment Medical Imaging Equipment (MRI, CT, X-ray)... Most often, they are both massive and expensive 6

7 Part 1 Large-class Nonstructural Examples Mechanical Cooling Tower Electrical Uninterruptible Power Supply (UPS) Cost 500K Cost 200K 7

8 Part 1 Performance Based Seismic Design (PBSD) A framework to establish levels of performance beyond life safety Building owners and other stakeholders select the appropriate performance level for a given building application Fundamental departure from present-day prescriptive requirements contained in model building codes Applicable to both building structures and nonstructural systems USA Implementation likely within 3 6 years 8

9 Part 1 Performance Based Seismic Design (PBSD) Major Implementation Impact Performance assessment includes statistical relationships between hazard intensity, dynamic response, damage, and loss Hazard functions Building response functions Damage functions Loss functions Loss measures expressed in terms of: Repair costs Casualties Time length of occupancy interruption 9

10 Part 1 PBSD Implementation Perspective Present-day equipment qualification involves seismic simulation testing representative test unit(s) Define a spectral demand And conduct a shake test Photo courtesy of Baltimore Aircoil Company 10

11 Part 1 PBSD Implementation Perspective Performance-based equipment qualification will require testing to performance limits A (g s ) New Performance Limit t = 30 sec 5% damping Design Margin Shock Response Spectra, Old Qualification Requirement Frequency, f ( Hz ) 11

12 Part 1 PBSD Implementation Perspective A (g s ) New Performance Limit Performance-based equipment qualification will require testing to performance limits t = 30 sec 5% damping t = 30 sec Design Margin Acceleration SRS ( g s ) Qualification Subset Shock Response Spectra, Old Qualification Requirement Frequency, f ( Hz ) Develop Damage Functions Fragility Surface Frequency f ( Hz ) Time t ( sec ) 12

13 Part 2 Damage Functions and Fragility Testing Requires multiple test samples (>> 1) Active operation performance assessment as a function of demand What is the value proposition for equipment manufacturers and suppliers? What options are available for testing? Must be practical to be accepted in industry Implementation is a critical aspect 13

14 Part 2 Fragility Testing Options Top-level Equipment Testing Active operations tested at highest assembly level Assess equipment performance during shake test Requires highly specialized large-scale seismic test facility or Bottom-level Device Testing Active operations tested at lowest assembly level Assess device performance during shake test Can be tested at OEM design center, no large-scale test facility required 14

15 Part 2 Fragility Testing Options Top-level Equipment Testing: performance tested at highest assembly level Building-level system inputs fed to equipment test unit Monitor equipment functions during shake test Pros Simulates end-use building application environment What you see installed is what you test Cons Top-level assembly is functionally complex Top-level assembly is physically large and heavy Top-level assembly is expensive Few test facility options Difficult to simulate building-level functional inputs during testing 15

16 Part 2 Fragility Testing Options Top-level Equipment Testing: performance tested at highest assembly level Building-level system inputs fed to equipment test unit Monitor equipment functions during shake test Pros Simulates end-use building application environment What you see installed is what you test Cons Top-level assembly is functionally complex Top-level assembly is physically large and heavy Top-level assembly is expensive Few test facility options Difficult to simulate building-level functional inputs during testing 16

17 Part 2 Fragility Testing Options Bottom-level Device Testing: performance tested at lowest assembly level Equipment-level system inputs fed to devise/module test unit Monitor devise/module functions during shake test Pros Bottom-level assembly is functionally less complex Bottom-level assembly is physically smaller and lighter Bottom-level assembly costs much less (multiple test units at reasonable cost) More test facility options (e.g., design center) Easier to simulate equipment-level functional inputs during testing Cons Internal structural transmission paths must be characterized Top-level assembly fragility becomes a composite calculation with uncertainties 17

18 Part 2 Fragility Testing Options Bottom-level Device Testing: performance tested at lowest assembly level Equipment-level system inputs fed to devise/module test unit Monitor devise/module functions during shake test Pros Bottom-level assembly is functionally less complex Bottom-level assembly is physically smaller and lighter Bottom-level assembly costs much less (multiple test units at reasonable cost) More test facility options (e.g., design center) Easier to simulate equipment-level functional inputs during testing Cons Internal structural transmission paths must be characterized Top-level assembly fragility becomes a composite calculation with uncertainties 18

19 Part 2 Device Testing is a Practical Alternative Many equipment types are too large and costly for testing at the top level of assembly especially when multiple test samples are required Device testing is an attractive option Implementation requires sub-system decomposition to determine device transfer functions 19

20 Part 3 Device Fragility Testing UPS Example 20

21 Part 3 Device Fragility Testing Nonstructural Nonstructural System System Diagram Seismic Demand Mechanical Elements Structural Transmissibility Interaction Seismic Demand Active Operation Elements UPS Example Clearance Envelope Force Resisting Skeleton () Device (1) Transmission Path From Device (1) / Interaction Device (1) Motion From Device (1) Device (2) Transmission Path From Device (2) / Interaction Device (2) Motion From Device (2) Building Floor (n) Motion Anchorage Analyze Mechanical Elements to Determine Performance Limits Transfer Function Using Analysis Or Modal Survey Mechanical Impedance Effects Device Demand Fragility Test Device To Performance Limits 21

22 Part 3 Device Fragility Testing Nonstructural Nonstructural System System Diagram Seismic Demand Mechanical Elements Structural Transmissibility Interaction Seismic Demand Active Operation Elements UPS Example Clearance Envelope Force Resisting Skeleton () Device (1) Transmission Path From Device (1) / Interaction Device (1) Motion From Device (1) Device (2) Transmission Path From Device (2) / Interaction Device (2) Motion From Device (2) Building Floor (n) Motion Anchorage Analyze Mechanical Elements to Determine Performance Limits Transfer Function Using Analysis Or Modal Survey Mechanical Impedance Effects Device Demand Fragility Test Device To Performance Limits 22

23 Part 3 Device Fragility Testing Nonstructural Nonstructural System System Diagram Seismic Demand Mechanical Elements Structural Transmissibility Interaction Seismic Demand Active Operation Elements UPS Example Clearance Envelope Force Resisting Skeleton () Device (1) Transmission Path From Device (1) / Interaction Device (1) Motion From Device (1) Device (2) Transmission Path From Device (2) / Interaction Device (2) Motion From Device (2) Building Floor (n) Motion Anchorage Analyze Mechanical Elements to Determine Performance Limits Transfer Function Using Analysis Or Modal Survey Mechanical Impedance Effects Device Demand Fragility Test Device To Performance Limits 23

24 Part 3 Device Fragility Testing Nonstructural Nonstructural System System Diagram Seismic Demand Mechanical Elements Structural Transmissibility Interaction Seismic Demand Active Operation Elements UPS Example Clearance Envelope Force Resisting Skeleton () Device (1) Transmission Path From Device (1) / Interaction Device (1) Motion From Device (1) Device (2) Transmission Path From Device (2) / Interaction Device (2) Motion From Device (2) Building Floor (n) Motion Anchorage Analyze Mechanical Elements to Determine Performance Limits Transfer Function Using Analysis Or Modal Survey Mechanical Impedance Effects Device Demand Fragility Test Device To Performance Limits 24

25 Part 3 System-level Composite Fragility Performance Limit Frame () Recombine elements to determine system-level performance limit: While accounting for device transmission paths (i.e., dynamic transfer functions) And including statistical uncertainties Frame () Device 1 Device 2 Performance Limit Device 2 Performance Limit Anchorage Performance Limit Device 1 System Limit =, Anch, Dev1, Dev2,... Active Operation Composite Damage Function 25

26 Part 3 Research Needs A set of consensus Best Practices to: Measure system transfer functions (in situ) Develop inelastic response reduction modifiers Develop consistent spectral envelopes from device transfer functions Conduct device fragility tests (random vibration vs. response spectrum and uni-axial vs. tri-axial) Include statistical uncertainties Validate techniques with test bed equipment Compare system-level test data with device-level composite approach Using complex large-class systems (i.e., mech and elect) 26

27 Part 3 Future-state Fragility Testing Nonstructural research cooperation is needed between academia and industry Implementation has to be a key research priority PBSD methods will revolutionize nonstructural compliance Now is the time to get it right 27

28 Part 3 Thank You QUESTIONS? COMMENTS? SUGGESTIONS? please.. 28