Foundations for Dynamic and Sensitive Equipment

Transcription

1 Fundatins fr Dynamic and Sensitive Equipment University f Minnesta - Structures Seminar Octber 30, 2015 Carl Nelsn, Ph.D., P.E. Tny Baxter, P.E.

2 ESI s Histry Our rts g back t a grup f prfessrs and graduate students at the U f M in the 1960 s 2

3 Wh We Are Tday! Minnesta based cnsulting engineering firm since 1970 Prvide specialized engineering services Specialists in high frce/shck, vibratin and nise cntrl Frm small medical devices and cnsumer prducts t sensitive buildings and large industrial facilities, ESI helps clients with advanced analysis and design. Our prfessinal engineering services are fcused in the areas f structural dynamics and design, vibratin cntrl, nise and acustics, and mnitring. 3

4 FEA and Structural Analysis 4

5 High Frce Structures and Fundatins 5

6 Vibratin Measurements and Mnitring 6

7 Vibratin Analysis fr Healthcare, Manufacturing and Research 7

8 Recent Prjects at U f M drilled piers SE crner f clean rm flr sil N (sil nt shwn) Nrthrp Balcnies Physics and Nantechnlgy Cleanrm Rec Center Expansin Cancer and Cardi Research Building 8

9 What we will talk abut tday 1. Types f Fundatins fr Equipment Fundatins fr Surces Fundatins fr Receivers 2. Vibratin Cntrl Methds fr Fundatins In grund Viper Example (Surce), Physics & Nantechnlgy Cleanrm Flr Example (Receiver) Islated Tyta Example 3. Technical Discussin f Dynamic Fundatin in Sil Mdel, Equatins Example Calculatins and Recmmendatins 4. References ACI Cmmittee 351, Bks 5. Clsing & Questins 9

10 Types f Fundatins Fr Equipment 1. Nt Dynamic (Inertial Frces are Nt Significant) 2. Fundatins fr Dynamic Surces a) Islated b) On grund 3. Fundatins fr Sensitive Receivers a) Islated b) On grund Surces Receiver? 10

11 Fundatin Types - nt dynamic - React frces, prvide a stable base and maintain alignment Nt Dynamic (Inertial Frces are Nt Significant) Multi-Axial Subassembly Testing (MAST) Labratry 11

12 Fundatins Fr Dynamic Surces React frces Prvide a stable base and maintain alignment Minimize mtin, n and ff fundatin 12

13 Islated Fundatin Fundatin in Grund Sensitive Receiver Dynamic Surce 2 MW Generatr X 1 Fundatin Fundatin in Sil M 1 X g K 1 C 1 Fundatin Sil Sil X 2 M 2 K 2 C 2 X 1 Press F 2 ( Fundatin M 1 K 1 C 1 X g Fundatin Press and fundatin Sil Tub and sil Tub and Sil 13

14 Frce Out/Frce In The Cncept f Transmissibility Transmissibility applies (exactly the same equatin!) t bth surce frce transmissibility and receiver displacement transmissibility 100 Frce Transmissibility F 10 1 Surce T F / F grund 0.1 Fractin f Critical Damping F grund Receiver T x x / grund f/fn x grund 14

15 Fundatins fr Dynamic Surces Sil Supprted Viper Test Rig at Virginia Internatinal Speedway Test item actuatrs 15

16 Fundatins fr Dynamic Surces Sil Supprted Viper Test Rig at Virginia Internatinal Speedway 16

17 Fundatins fr Dynamic Surces Air Munt Islated with Fundatin 17

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19 Fundatin Islatin with Air Munts High frce Mass Air Springs - Attenuated frce transmitted t fundatin - Minimize mtin at actuatr base 19

20 Sil Supprted Fundatins fr Sensitive Receiver Overview f Cncepts Slab Typical Wavelength = ft Engineered Fill 1. Simple Thick Slab n Grund Wavelength Effect Criteria 125 u"/s --- Measured > 300 u"/s Thick Slab Slab-n-Grade Criteria 125 u"/s --- Measured ~ 100 u"/s Flr Structure Sand Tall Islated Caissns Sand Air Space Auger Cast Piles Bedrck 2. Islated Slab fr Electrn Micrscpy Center - Shepherd Labratries Bedrck 3. Physics and Nantechnlgy Cleanrm U f M 20

21 Fundatins fr Sensitive Equipment Islated with Varius Types f Islatrs Sensitive Equipment Islatin Techniques Air Munts (<2 Hz) Steel Springs (2-5 Hz) Resilient Pad r Sheets (>6 Hz) Entire Building Islatin Drachen-Center Basel Switzerland 21

22 What d all these fundatins have in cmmn? Rigid Fundatin n Elastic Halfspace under harmnic lading P() t i t P e r, m G,, 22

23 Tw Minutes n Elastic Wave Prpagatin P Waves Cmpressin (fastest) S Waves Shear Rayleigh Waves V Speed clse t that f S waves Amplitude decreases with Accunts fr 2/3 f the energy s G V P 2G 1 r E (1 )(1 2 ) (See Figure 3-16 n p. 91 in Richart, Hall, and Wds) 23

24 Vibratin Amplitude - I nches/secnd Predicting Vibratin Versus Distance LRT Vibratin Amplitude vs. Distance z( ). r 12 z g ( ). r 12. z lim r Gemetric Damping Only: z g ( r ) z. 1 1 r r Gemetric & Material Damping: z( r ) z exp. r r 1 r r Dista nce - Fe et 24

25 Sme Histry Develpment f Techniques Early Bussinesq (1885), Lamb (1904) static, dynamic lad n the surface f elastic halfspace Riessner (1936) Dynamically laded, rigid circular fundatin n elastic halfspace Lysmer and Richart Dynamic Respnse f Ftings t Vertical Lading, ASCE Jurnal f the Sil Mechanics and Fundatins Divisin, January Lysmer s Analg Numerical Methds Many Cntributrs FEA, Bundary Element Methd Besks and C-Wrkers and the University f Minnesta (1970s-80s) 25

26 Appraches t the Dynamic Fundatin Prblem Cmplicated! Still Cmplicated! Winkler Fundatin Plate n Elastic Halfspace Rigid Plate n Elastic Halfspace But Lysmer s Analgue (1966) 26

27 Lysmer s Analg i t P() t P e F ( ) P F ( ) e it k F F i F ( ) ( ) ( ) Intrducing the dimensinless ratis (1 Ba) i a i 1 (1 Ba ) a (1 Ba ) a F is a dimensinless displacement functin with real and imaginary parts a c 2 k n km B 2 c M F 1 (1 Ba ) a Magnificatin Factr Textbk s far, but with slightly unfamiliar ntatin 27

28 Simple Damped Oscillatr i t P() t P e Lysmer s Analg F 1 (1 Ba ) Mdel a Rigid Circular Fundatin n Elastic Halfspace G,, i t P() t P e r, m a k c k 2 n Static vertical stiffness Dimensinless frequency c k r V s a r 4Gr k 1 G r V s km B 2 c i t m c k P e Dimensinless mass Equatin f mtin c k r V s B 2 m Vs 1 m k r 4 r 1 1 Vs 2 kr i t m c k k P e 28

29 Lysmer s Analg G,, i t P() t P e r, m kr i t m c k k P e 1 1 Vs 29

30 Magnificatin Factr vs. Frequency and Mass Rati B 5 M F 1 (1 Ba ) 0.85 a ) ( B 2 B 1 m 4 r 2 B 1 B 0.5 B 0 a r V s See Fig. 11 f Lysmer (1966) t see hw well this cmpares t the elastic halfspace slutin 30

31 Sample Calculatins Reciprcating Cmpressr Sil prperties, medium dense silty sand V s 750 ft 115 lbm 2 s ft 3 G V s S allwable 2000psf 0.35 Fundatin pad prperties 13962psi bl L 25 ft b 15 ft r ft t 4.5ft 2 W f r t150 pcf lbf 4G r k lbf in Vertical stiffness Cmpressr Weight W equip 50000lbf W f W equip bl W f W equip m g B f n 2 m 3 r W f >5 W equip 808psf < 0.5S allwable 1000psf k m s M F Ttal mass f fundatin plus equipment Mass rati Vertical natural frequency 1 (1 Ba ) 0.85 a ) ( Nte that B will generally be in this range B 0.5 B 0 a r V s 31

32 Sample Calculatins Mre Plts In terms f actual frequency M i 2 2 f i 1 f n a i 1 f n 19.06Hz M i 0.4 M i f i 100 Hz f i Hz 32

33 Velcity (micr in/sec) Acceleratin (micr g's) Displacement (in) Sample Calculatins Let s get dwn t sme real numbers. Suppse that the cmpressr exerts a vertical frce f 4500 lb at a frequency f 600 rpm (10 Hz). P 4500 lbf P in in 10 6 in g 10 6 g k Displacement vs frequency P M k P k M i in Velcity in micr in/sec vs frequency f i Hz Frequency (Hz) Acc eleratin in micr g's vs frequency P 2f i M i k in s f i 2 P M i k g f i Hz f i Hz 33

34 Sample Calculatins Let s see hw this cmpares t sme vibratin criteria 34

35 Sample Calculatins Frces exerted by seismic tables with heavy specimens can be large The system shwn abve has a 4m x 4m table with 8 actuatrs. The fur vertical actuatrs are capable f generating a ttal f 343 kn (77 kips) at frequencies frm 1 t 30 Hz. Nte the size f the fundatin mass reacting the actuatr frces.. 35

36 Velcity (micr-in/s rms) Velcity (micr-in/s rms) Acceleratin (in/s2) Acceleratin (in/s2) Case Study Prject / Lcatin: P1721- U f M Physics & Nantech Building Measurement ID: File: TEST004.AE2 Recrd Date and Time :12/20/2010 1:35:53 PM Fundatins fr Sensitive Equipment- Sil Supprted Date: 20-Dec-10 Channel 3: Sidewalk NW crner Cnditins: Delivery truck leaving by CH 4 Channel 4: Asphalt SW crner Physics and Nantechnlgy Clean Flr Design at U f M Setup: 90% verlap, hanning windw, delta f = Hz Vibratin Criteria VC-C (green), VC-D, VC-E Channel 3 Trigger Channel 4 Trigger Time (s) Time (s) Channel 3 Peakhld Spectrum Channel 4 Peakhld Spectrum , , Freq (Hz) Freq (Hz) Sample f Grund Vibratin Measurements Prir t Cnstructin Measurement Lcatins 36

37 Case Study Fundatins fr Sensitive Equipment- Sil Supprted Physics and Nantechnlgy Clean Flr Design at U f M Auger Cast Pile Placement N Fundatin Plan Pile Tp and Flr Detail 37

38 Velcity - (in/sec) Case Study Fundatins fr Sensitive Equipment- Sil Supprted Physics and Nantechnlgy Clean Flr Design at U f M 1/3 Octave Velcity vs. Frequency Flr Respnse at Vistec-E-Beam Predicted Respnse at 75 Predicted Respnse at 893 Predicted Respnse at 898 Predicted Respnse at 4 Predicted Respnse at 126 VC-E drilled piers SE crner f clean rm flr sil N 20 (sil nt shwn) Frequency (Hz) Predicted Velcity n Cleanrm Flr FEA Mdel (COSMOS) 38

39 ACI Cmmittee 351 Fundatins fr Equipment and Machinery Active Cmmittee Dcuments: 351.1R-12: Reprt n Gruting between Fundatins and Bases fr Supprt f Equipment and Machinery 351.2R-10: Reprt n Fundatins fr Static Equipment 351.3R-04: Fundatins fr Dynamic Equipment : Specificatin fr Installatin f Cementitius Gruting between Fundatins and Equipment Bases Specificatin fr Installatin f Epxy Grut between Fundatins and Equipment Bases Dcuments Under Develpment: 351.3R: Fundatins fr Dynamic Equipment 351.4M-14: Specificatin fr Installatin f Cementitius Gruting between Fundatins and Equipment Bases 351.5M-15: Specificatin fr Installatin f Epxy Gruting between Fundatins and Equipment Bases 39

40 Wrap Up Imprtant Tpics We Have Nt Talked Abut Tday Rtatinal and Hrizntal Mdes Embedment Effects Strength Requirements Anchrage Numerical Methds/Sftware Questins? Thank yu fr inviting us! 40