Update LADOTD Policy on Pile Driving Vibration Management (09-1GT) MINGJIANG TAO, PH.D., P.E. WORCESTER POLYTECHNIC INSTITUTE JANUARY, 2011

Transcription

1 Update LADOTD Policy on Pile Driving Vibration Management (09-1GT) MINGJIANG TAO, PH.D., P.E. WORCESTER POLYTECHNIC INSTITUTE JANUARY, 2011

2 Presentation Outline Research Objectives Methodology Results Threshold PPV limits Approach to determine a pre-construction survey distance & a monitoring distance Conclusions and Recommendations

3 Research Incentives How large a vibration monitoring area is enough? Strongly dependent on: dynamic sources soil conditions susceptibility of structures

4 Research Objectives Update current LA DOTD policy, and provide implementable recommendations for monitoring and control of ground and structure vibrations

5 Methodology

6 Methodology Literature Review Questionnaire Survey Collect data from case history project in Louisiana Data analysis

7 Pile driving, wave propagation, & wave attenuation Scaled-distance concept

8 Preconstruction survey distance vs. vibration monitoring distance R monitoring R survey Pile structural damage: PPV<0.5 in/s R monitoring =R survey

9 Determine pre-construction survey distance Estimate the Monitoring Area Range 1. Upper limit PPV 10 Scaled Distance(horizontal, Max Rated Energy)-PPV k=0.93, n=1 Chart PPV vs. SD 2. Determine threshold PPV value PPV(in./s) Step 2 Step 1 3. SD corresponding to threshold PPV Step Scaled distance(ft/sqrt(ft-lbs))

10 Determine pre-construction survey distance 4. Vibration monitoring distance Monitoring Distance (ft) Monitoring Distance vs. Rated Energy Vibration Monitoring Distance Step 4 Rated Energy of the Hammer Applied Rated Energy (ft-lbs)

11 Step 1: Determine vibration monitoring distance A statistical approach: Best-fit line Confidence level line Prediction level line Back-calculation approach (best-fit line)

12 Determine vibration monitoring distance: Step 1 Confidence level line: 95 % Confidence Interval if you collected ground vibration data many times, 95 times out of 100, the mean of the dataset would be in this range. Prediction level line: 95 % Prediction Interval means that about 95 % of the time, the next ground vibration measurement you make will be inside this interval.

13 Step 2: Threshold PPV value Maximum Peak Particle Velocity That Varies with Frequency 1. USBM criteria PARTICLE VELOCITY, in/sec RI 8507 APPENDIX B. -- ALTERNATE BLASTING LEVEL CRITERIA 0.03 in 0.5 in/s Plaster 0.75 in/s Drywall OSM Modificaton 0.75 in/s 0.5 in/s in 2 in/s Current LA DOTD specification FREQUENCY, Hz

14 Determining threshold PPV value 2. Germany criteria Current LA DOTD specification

15 Determining threshold PPV value 3.The Swedish Standard

16 Determining threshold PPV value- The Swedish Standard Residential house: V= 9 x 1.00 x 0.75 x 0.60 = 4.05 mm/s (0.16 in/s) This value is less than 6 mm/s (0.24 in/s) used as a limit for human response in the German Standard DIN 4150 (1986). Industrial building: V = 9 x 1.20 x 1.20 x 1.00 = mm/s (0.51 in/s) This value is very small for industrial building built with reinforced concrete, steel, and pile foundations. Too conservative

17 Determining threshold PPV value-russia criterion 4. Russia Limits of Structure Vibration The frequency-independent safe limit of 51 mm/s (2 in/s) can be chosen for the PPV of structural (not ground) vibrations for multi-story residential, commercial and industrial buildings. There will be practical obstacles for LA DOTD implementing this criterion

18 Determining threshold PPV value 5.Maximum Peak Particle Velocity Independent of Frequency (by Woods 1996) Structure and Condition Limiting Particle Velocity (in./sec) (mm/sec) Historic and some old structures 0.5 (12.7) Residential structures 0.5 (12.7) New residential structures 1.0 (25.4) Industrial building 2.0 (50.8) Bridges 2.0 (50.8)

19 Threshold PPV limits for LA DOTD Structure and Condition Limiting Particle Velocity (in./sec) (mm/sec) Historic and some old structures 0.1 (2.5) Residential structures 0.5 (12.7) New residential structures 1.0 (25.4) Industrial building 2.0 (50.8) Bridges 2.0 (50.8) o Simple and easy to be implemented. o Reasonably conservative: assumed a magnification factor of 4, structural vibration is 2 in./sec.

20 Threshold PPV limits-further confirmation with dynamic FEM simulations

21 Results

22 Collected Available Data (a) a list of necessary data and information required for pile-driving vibration risk management Available Information Huey P. Long Bridge Widening Project Millerville Road over Honey Cut Bayou Bayou Plaquemine Bridge Replacement Project The Rigolets Pass Bridge Project Project Description Hammer and Pile Details Penetration Depth Data Energy transferred to Plies Vibration Monitoring Soil Profile PPV 3 directional Velocity Velocity Vector Max PPV

23 10 Millerville Bayou Road Rigolets Bayou Degleises Causeway Tickfaw Amite HPL Peak Particle Velocity (in./s) PPV = 0.080(SD) R 2 =0.404 PPV = 0.081(SD) Woods & Jedele s, Soil III Scaled Distance (ft/sqrt(ft-lbs)) PPV = 0.015(SD) Woods & Jedele s, Soil II

24 10 Millerville Bayou Road Rigolets Bayou Degleises Causeway Tickfaw Amite HPL Peak Particle Velocity (in./s) PPV = 0.350(SD) -1.0 PPV = 0.211(SD) -1.0 PPV = 0.080(SD) R 2 =0.404 PPV = 0.1(SD) -1.0 PPV = 0.081(SD) Woods & Jedele s, Soil III Scaled Distance (ft/sqrt(ft-lbs)) PPV = 0.015(SD) Woods & Jedele s, Soil II

25 Pre-Construction Survey Distance Peak Particle Velocity (in./s) Millerville Bayou Road Rigolets Bayou Degleises Causeway Tickfaw Amite HPL PPV = 0.350(SD) -1.0 PPV = 0.211(SD) Scaled Distance, SD (ft/sqrt(ft-lbs))

26 Determine vibration monitoring range Step 4 (, PPV=0.5 in./s, (Hammer energy transfer efficiency=50%) Rated energy (W) (ft lbs) 99%PL k=0.21; n=-1 Monitoring distance (ft) k=0.35; n=-1 Monitoring distance (ft) FL DOT Monitoring distance (ft) Hammer Model Bruce SGH 3013 hydraulic hammer 282, DELMAG D46 23, Diesel Hammer 105, PILECO, D19 42, Diesel Hammer 42, Boh/Vulcan 08 24, Boh/Vulcan 09 27, Boh/Vulcan , Conmaco 300E5,Air Hammer 149, I.C.E 42 S, Single Acting Diesel 42, I.C.E 60S, Single Acting Diesel 60, I.C.E I 46v2, Single Acting Diesel 10, , APE Model D , , I.C.E I 30 Diesel Hammer 35, ,

27 Use the chosen pile driving hammer to determine Vibration Monitoring Distance (based on 50% energy transfer efficiency of hammer and threshold PPV=0.5 in/s) 500 Current LA DOTD specification Monitoring distance (ft) W 0.30 W 0.25 W W (ft lbs) D (ft) 100, , , % Prediction level BackCalculation (k=0.35; n=1) Fl DOT specification 10 10, , ,000 Rate energy of driving hammer (ft-lbf)

28 Use the chosen pile driving hammer to determine Vibration Monitoring Distance (based on 50% energy transfer efficiency of hammer and threshold PPV=0.1 in/s) for special conditions W Monitoring distance (ft) % prediction level (k=0.211, n=-1); threshold PPV=0.1 in./s 10 10, ,000 Rate energy of driving hammer (ft-lbf)

29 Conclusions and Recommendations

30 Vibration Monitoring Distance for LA DOTD The current LA DOTD specification is too conservative (500 ft) Use 200-ft for general conditions Use 500-ft for special cases (loose sand deposits; historic buildings; etc.)

31 Implementation Flow-chart For a given pile driving project with: Designed pile bearing capacity & chosen driving hammer o Pre construction survey o Estimated Vibration Monitoring Distance (VMD) Incorporate site specific conditions: o Distances of surrounding buildings from driven piles o Any historic buildings within EVMR o Any building housing sensitive equipment within VMD Verify adequacy of actual VMD during driving testing piles Modify VMD and/or driving design if actual VMD is not adequate Use verified VMD for driving production piles

32 Engineering Mitigation Measures Pre-poring prior to pile installation Selecting proper hammers to reduce hammers energy Using cast-in-place piles or non-displacement piles Drilling shaft foundation instead of driven piles

33 Conclusions and Recommendations Threshold PPV limits are determined for LA DOTD. A procedure to determine Pre-construction survey area & Vibration Monitoring Distance is developed. An updated specification to managing pile-driving induced risk has been developed.

34 Questions

35 Acknowledgements The project is financially supported by the Louisiana Transportation Research Center and Louisiana Department of Transportation and Development (LA DOTD) (09-1GT). Gavin Gautreau, Dr. Doc Zhang, Dr. Ching Tsai, and other PRC members Mo Zhang (WPI graduate student) Mark Svinkin (Vibroconsult)

36 Determining threshold PPV value Dynamic settlement (presence of loose sand) Consolidation settlement (presence of soft clay) Threshold shear strain concept Relative density, Dr(%) Description 0 20 Very loose Loose Medium Dense Very dense NHI (2002) Manual on Subsurface Investigations: Geotechnical Site Characterization

37 Determining threshold PPV value > 0.01%

38 Determining threshold PPV value No Determine if loose sand exists based on CPT or SPT results Yes Dynamic settlement is not a concerned issue. Compare γ of loose sand to the γ t (0.01%).

39 Determining threshold PPV value Replaced with PPV =k(sd) (-n) > 0.01% The shear wave velocities are in the range of ft/s for most sands The threshold PPV values for preventing dynamic settlement are calculated as a range of in/s