Thermal Integrity Testing of Drilled Shafts. AASHTO SOC Conference August 4, 2009 Chicago, Illinois Presented by: Gray Mullins, Ph.D., P.E.

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1 Thermal Integrity Testing of Drilled Shafts AASHTO SOC Conference August 4, 2009 Chicago, Illinois Presented by: Gray Mullins, Ph.D., P.E.

2 Overview Background Case Studies Integrity Evaluation Conclusions

3 Background Factors Affecting Anomaly Formation in Drilled Shafts (FDOT ) Thermal Integrity Testing of Drilled Shafts (FDOT ) Foundation Health Monitoring (FHWA ) Attenuating Mass Concrete Effects in Drilled Shafts (FDOT )

4 Background Mass concrete effects from hydration energy can be harmful in two ways: Differential temperature stresses / cracking High temperature curing errors Hydration energy can be helpful as it produces a distinguishable heat signature.

5 Background Differential Temperature in mass concrete has immediate adverse effects in the form of cracking...(typically deg F) Excessively high curing temperatures can affect long-term durability from Delayed Ettringite Formation, DEF (>160 deg F).

6 When s Concrete Mass? Differential Temperature Limit Peak Temperature Cut-off Mass Concrete Geometry Limit Drilled Shaft Diameter Limit (pending) Performance-based Specification (Based on first two conditions)

7 Geometric Guidelines Mass Concrete Geometry Limit When Volume(ft 3 )/Surface Area(ft 2 ) > 1 ft When minimum dimension > 3 ft Drilled Shaft Diameter Limit When diameter > 6 ft (FDOT 2006)

8 Geometry Criterion Applied to Shafts 2 Mass Concrete Volume - Area Ratio (ft) 1 Volume / Area Threshold Shaft Diameter (ft) Shaft Length (ft)

9 Case Studies: Hoover Dam Built More than 5 million yd 3 of concrete Equivalent to 2 lane road coast to coast (w/sidewalks) 600 miles of 1 steel cooling tubes 100 yr estimated cooling

10 Ringling Causeway Bridge Built ft diameter shafts Standard FDOT shaft mix (4 ksi) Winter construction No cooling system

11 Ringling Causeway Bridge Shaft Curing Temperature Peak 156F (69C) Center Temperature (degrees F) Max Diff. 67F (37C) Edge Temperature (degrees C) 40 Bay Water 2 20 Air Feb Feb Mar Mar Mar Mar-02

12 Predicting Mass Concrete Conditions Must know mix design with detailed cement and flyash reports (can change monthly) Must know geometry of shaft or other concrete element in question Must know environmental conditions (e.g. air temp, soil type, soil temp, etc.)

13 Hydration Energy (Schindler, 2005) Cement Energy Production Total Energy Production

14 Hydration Energy (Schindler, 2005) Degree of Hydration Rate of Energy Production

15 Input Parameters (from concrete supplier)

16 Ringling Causeway Bridge (Modeled and Measured) Shaft Core Temperature Core Temperature

17 Single Shaft Heat Signature S46 S37 S28 S S1 S10

18 Thermal Integrity Evaluation Drilled shafts lack reliable means of assuring good quality construction outside reinforcing cage. Temperature generation in concrete provides a useful mechanism to detect anomalies in shafts.

19 Why Test Shaft Integrity? 1-4 & US 192

20 Why Test Shaft Integrity? 1-4 & SR 400

21 Why Test Shaft Integrity? 1-4 & SR 400

22 Why Test Shaft Integrity? Quality Assurance of drilled shafts relies heavily on good construction practices. The most popular method of post construction evaluation is Cross Hole Sonic Logging which cannot detect anomalies outside the cage New thermal integrity method uses Infra-red Thermal Imaging of the entire shaft length.

23 Cross-hole Sonic Logging Drilled Shaft Anomaly Reinforcement Cage CSL Logging Tubes

24 Sonic Echo Testing Signal Signal Anomaly Reflection Anomaly Formation Drilled Shaft Toe Reflection

25 Thermal Integrity Evaluation Drilled Shaft Reinforcement Cage Logging Tubes

26 Thermal Integrity Evaluation Drilled Shaft Reinforcement Cage Logging Tubes Normal Heat Signature

27 Thermal Integrity Evaluation Drilled Shaft Anomaly Reinforcement Cage Logging Tubes

28 Thermal Integrity Evaluation Drilled Shaft Anomaly Reinforcement Cage Logging Tubes Interrupted Heat Signature

29 Thermal Integrity System Depth encoder Data acquisition Access Tubes Lead Wire to Infrared Probe

30 Field Trials RW Harris Site Site Layout & Construction Instrumentation Infrared Integrity Testing Cross-hole Sonic Logging Pile Integrity Testing

31 Site Layout 4 Thermal Monitoring Access Tubes 1 Water Table Well (W.T. 20 inches Below Surface) 2D 1/2D Water Table Well 1/4D 1D Proposed Shaft Location (4 ft diameter)

32 Drilled Shaft Construction 48 in. diam.; 25 ft deep Polymer Slurry 54 in. Temporary Casing (6 ft Depth) Concrete Parameters F c = 4000 psi Slump = 6 to 9 inches w/c ratio = 0.43 Coarse Aggregate = #57 Stone

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34 Reinforcement Cage 36 in Diameter 16 No. 11 Reinforcement No. 4 Shear 12 in O.C. 6 Logging Tubes (3 PVC & 3 Steel) 2 Levels of Sand Bag Anomalies

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36 Instrumentation 16 Thermal Couples 2 Levels of 4 Strain Gages

37 Test Shaft 183F Peak Core Logging Tubes Reinforcement Cage Logging tube 8ft from edge Logging tube 1ft from edge

38 0 Thermal Logging Tube 1 Temperature (V) CSL Logging Tubes Thermal Logging Tubes :00 PM 12:00 AM A 3:00 AM Depth (ft) :00 AM 9:00 AM B Known Anomalies Steel Logging Tubes Known Anomaly 5 3 PVC Logging Tubes 5 3 Cross-Section A Top Anomaly Cross-Section B Bottom Anomaly

39 Signal Matched Results

40 Cross-hole Sonic Logging

41 Cross-hole Sonic Logging Results Tubes 4-6 Tubes 2-4 Tubes A B Cross-Section A Top Anomaly Cross-Section B Bottom Anomaly CSL Logging Tubes Thermal Logging Tubes 6 2 Steel Logging Tubes Known Anomaly 6 2 PVC Logging Tubes 4 4

42 Pile Integrity Testing

43 Pile Integrity Test Results Second anomaly (16 ft) not detected Known Anomaly (approx. 8 ft down)

44 Thermal Integrity Evaluation Field Measurements Model Soil / Shaft System Compare Predicted and Measured Signal Match Model Results Modeled shape determines amount/degree of anomalous conditions

45 St. Augustine Bridge of Lions

46 Bridge of Lions Pier 25 Shaft 3 3ft diameter

47 Temperature (deg F) Temperature (deg F) Depth (ft) Elevation (ft) BOC Model Results Measured Results Tube 1 Tube Tube 3

48 Bridge of Lions Concreting Curve

49 0 Temperature (deg F) Temperature (deg F) Elevation (ft) BOC Elevation (ft) Tube Tube 1 Tube Tube 2 Tube Tube 3 110

50 Modeled Temperature (deg F) Measured Temperature (deg F) Sample Data Model Norm Depth (ft) Modeled Neck Model Norm Depth (ft) Tube1 Tube1 Tube2 Tube2 Tube3 Tube4 Tube3 Model Norm Tube4 Modeled Neck 30 30

51 1 Cage Alignment F Soil Temp 54" excavation 50F Soil Temp Temperature (F) " cage / tube diameter T3 T S1 S10 S19 S46 S37 S Position (in)

52 Cage Alignment

53 WSDOT Nalley Valley I-5/SR16

54 WSDOT Nalley Valley I-5/SR16 Modeled and Measured Core and Tube Temps ft up Temperature (deg F) Time (hrs) 26ft up 36ft up Air Model Center Model Cage

55 Pier 6 Shaft B Temperature (deg F) Depth (ft) 0 5 Top of Perm Casing Construction Joint Bottom of Perm Casing 9' Auger w/ 1' Reamer ' Digging Bucket w/ 2' Reamer ' Auger Elevation (ft) Avg Field Testing Model Normal T/C Data SP -SM / SP T N 33 SM / SP T N 42 SP -SM / SP T N 73 SM / SP T N 56 SP -SM / SP T N 78 SW-SM / SP T N ' Cleanout Bucket Bottom of Shaft SM / SP T N 84

56 Temperature (deg F) Cage Alignment T1_ T2_2 T3_2 Tube Stickup 30 T4_2 Depth (ft) T5_2 T6_2 Water Table Sloughing 45 T7_2 50 T8_ T9_2 T10_2 Tube No Average Tube No. 1 75

57 Temperature (deg F) Cage Alignment T1_ ft T2_2 T3_2 N Increasing Tube Nos. 30 T4_2 TUBE 1 Depth (ft) T5_2 T6_2 T7_2 T8_ T9_2 T10_2 Average 125F 150F 175F 25 ft 75

58 Temperature (deg F) Cage Alignment T1_ T2_2 T3_2 N Increasing Tube Nos ft T4_2 TUBE 1 Depth (ft) T5_2 T6_2 T7_2 T8_ T9_2 T10_2 Average 125F 150F 175F 30 ft 75

59 Temperature (deg F) Cage Alignment T1_ T2_2 T3_2 N Increasing Tube Nos. 30 T4_2 TUBE 1 Depth (ft) ft T5_2 T6_2 45 T7_2 50 T8_ T9_2 T10_2 Average 125F 150F 175F 35 ft 75

60 Temperature (deg F) Cage Alignment T1_ T2_2 T3_2 N Increasing Tube Nos. 30 T4_2 TUBE 1 Depth (ft) ft T5_2 T6_2 45 T7_2 50 T8_ T9_2 T10_2 Average 125F 150F 175F 40 ft 75

61 Temperature (deg F) Cage Alignment T1_ T2_2 T3_2 N Increasing Tube Nos. 30 T4_2 TUBE 1 Depth (ft) T5_2 T6_ ft T7_2 50 T8_ T9_2 T10_2 Average 125F 150F 175F 45 ft 75

62 Temperature (deg F) Cage Alignment T1_ T2_2 T3_2 N Increasing Tube Nos. 30 T4_2 TUBE 1 Depth (ft) T5_2 T6_ ft T7_2 T8_ T9_2 T10_2 Average 125F 150F 175F 50 ft 75

63 Temperature (deg F) Cage Alignment T1_ T2_2 T3_2 N Increasing Tube Nos. 30 T4_2 TUBE 1 Depth (ft) T5_2 T6_2 T7_ ft T8_2 T9_2 T10_2 Average 125F 150F 175F 55 ft 75

64 Temperature (deg F) Cage Alignment T1_ T2_2 T3_2 N Increasing Tube Nos. 30 T4_2 TUBE 1 Depth (ft) T5_2 T6_2 T7_2 T8_ ft T9_2 T10_2 Average 125F 150F 175F 60 ft 75

65 Temperature (deg F) Cage Alignment T1_ T2_2 T3_2 N Increasing Tube Nos. 30 T4_2 TUBE 1 Depth (ft) T5_2 T6_2 T7_2 T8_ ft T9_2 T10_2 Average 125F 150F 175F 65 ft 75

66 Temperature (deg F) Cage Alignment T1_ T2_2 T3_2 N Increasing Tube Nos. 30 T4_2 TUBE 1 Depth (ft) T5_2 T6_2 T7_2 T8_ ft T9_2 T10_2 Average 125F 150F 175F 70 ft 75

67 Cage Alignment (at 40 ft) Depth 40 ft Highest Measured Temp Worst Case Cover (7.5in) Temperature (F) Lowest Measured Temp Lateral Temp Dist (model) Cage Diameter at tubes Excavation Diameter Horizontal Position

68 Thermal Testing Timeframe 4000 P Mix Design 160 4ft Diameter 6ft Diameter 8ft Diameter ft Diameter Temperature (deg F) Optimal Testing Window Acceptable Testing Window Time (hrs)

69 Conclusions Infra-red Thermal Integrity testing shows remarkable capabilities to detect anomalies outside the reinforcing cage (bulges and necks) Cross-hole Sonic Logging showed no problems with the shaft integrity in spite serious cross sectional reduction Pile Integrity Testing showed an irregularity of unknown proportion at one of the two anomaly locations but not the second

70 Conclusions Cage alignment is easily identified and can confirm minimum cover / cage alignment Thermal modeling provides insight into a normal shaft signature as well as mass concrete conditions Thermal models can be signal matched field measurements to ascertain location and size of anomalies.

71 Home About FGE Services Projects Contact 712 East Alsobrook Street, Suite 3 Plant City, FL Office: (813) Fax: (813) engineering@foundations.cc Infrared Integrity Services available at