Thermal Integrity Testing of Drilled Shafts

AASHTO SOC Conference August 4, 2009 Chicago, Illinois Presented by: Gray Mullins, Ph.D., P.E. Overview

Background Case Studies Integrity Evaluation Conclusions Background

Factors Affecting Anomaly Formation in Drilled Shafts (FDOT 2000-2004) Thermal Integrity Testing of Drilled Shafts (FDOT 2004-2006) Foundation Health Monitoring (FHWA 2007-2008) Attenuating Mass Concrete Effects in Drilled Shafts (FDOT 2007-2009) 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. Background

Differential Temperature in mass concrete has immediate adverse effects in the form of cracking. . .(typically 35-40 deg F) Excessively high curing temperatures can affect long-term durability from Delayed Ettringite Formation, DEF (>160 deg F). 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) Geometric Guidelines

Mass Concrete Geometry Limit 3 2 When Volume(ft )/Surface Area(ft ) > 1 ft

When minimum dimension > 3 ft Drilled Shaft Diameter Limit

When diameter > 6 ft (FDOT 2006) Geometry Criterion Applied to Shafts

2 8 Mass Concrete 7

5 Volume / Area Threshold 1 4

3 Volume Area - Ratio (ft) Shaft Diameter (ft)

0 0 1020304050607080 Shaft Length (ft) Case Studies: Hoover Dam

Built 1932 - 1935 More than 5 million yd3 of concrete Equivalent to 2 lane road coast to coast (w/sidewalks) 600 miles of 1” steel cooling tubes 100 yr estimated cooling Ringling Causeway Bridge

Built 2001-2003 9 ft diameter shafts Standard FDOT shaft mix (4 ksi) Winter construction No cooling system Ringling Causeway Bridge Shaft Curing Temperature

180 Peak 156F 160 (69C) 72

62 140 Center 52 120 Max Diff. 67F (37C) 42 100 32 Edge 80 22 60 12 Temperature (degrees F) Temperature (degrees C) 40 Bay Water 2

20 Air -8

0 -18 25-Feb-02 27-Feb-02 01-Mar-02 03-Mar-02 05-Mar-02 07-Mar-02 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.) Hydration Energy (Schindler, 2005)

Cement Energy Production

Total Energy Production Hydration Energy (Schindler, 2005)

Degree of Hydration

Rate of Energy Production Input Parameters (from concrete supplier) Ringling Causeway Bridge (Modeled and Measured) Shaft Core Temperature

Core Temperature 80 70 60 50 40 30 20

1 4 7 Single ShaftHeatSignature 10 13 16 19 22 25 28 31 34 37 40 43 46 49 S1 S10 S19 S28 S37 S46 20-30 30-40 40-50 50-60 60-70 70-80 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. Why Test Shaft Integrity?

1 - 4 & US 192 Why Test Shaft Integrity?

1 - 4 & SR 400 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. Cross-hole Sonic Logging

Drilled Shaft

Anomaly Reinforcement Cage

CSL Logging Tubes Sonic Echo Testing

Signal Signal

Anomaly Reflection

Anomaly Formation

Drilled Shaft

Toe Reflection Thermal Integrity Evaluation

Drilled Shaft

Reinforcement Cage

Logging Tubes Thermal Integrity Evaluation

Drilled Shaft

Reinforcement Cage

Logging Tubes

Normal Heat Signature Thermal Integrity Evaluation

Drilled Shaft

Anomaly Reinforcement Cage

Logging Tubes Thermal Integrity Evaluation

Drilled Shaft

Anomaly Reinforcement Cage

Logging Tubes

Interrupted Heat Signature Thermal Integrity System

Depth encoder

Data acquisition

Access Tubes Lead Wire to Infrared Probe Field Trials – RW Harris Site

Site Layout & Construction Instrumentation Infrared Integrity Testing Cross-hole Sonic Logging Pile Integrity Testing Site Layout

4 Thermal Monitoring Access Tubes 1 Water Table Well (W.T. 20 inches Below Surface)

2D Water Table Well 1/2D 1/4D

Proposed Shaft 1D Location (4 ft diameter) 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

Reinforcement Cage

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

Instrumentation

16 Thermal Couples 2 Levels of 4 Strain Gages Test Shaft

Logging Tubes

Logging tube 183F 8ft from edge Peak Core Reinforcement Cage

Logging tube 1ft from edge Thermal Logging Tube 1 CSL Logging Tubes Temperature (V) Thermal Logging Tubes 3 1 5 1.2 1.3 1.4 1.5 1.6 1.7 0

5 9:00 PM A 12:00 AM 3:00 AM 10 6:00 AM 9:00 AM Depth (ft) Depth 15 B Known Anomalies 20

25 1 1 Steel Logging Tubes

Known Anomaly

PVC Logging Tubes 5 3 5 3

Cross-Section A Cross-Section B Top Anomaly Bottom Anomaly Signal Matched Results Cross-hole Sonic Logging Cross-hole Sonic Logging Results 2 4 6 Tubes 4 - 6 Tubes 2 - 4 Tubes 2 - 6

CSL Logging Tubes Cross-Section A Cross-Section B Thermal Logging Tubes Top Anomaly Bottom Anomaly

Steel Logging Tubes 2 2 6 6 Known Anomaly

PVC Logging Tubes

4 4 Pile Integrity Testing Pile Integrity Test Results

Second anomaly (16 ft) not detected

Known Anomaly (approx. 8 ft down) 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 St. Augustine Bridge of Lions Bridge of Lions Pier 25 – Shaft 3 3ft diameter Temperature (deg F) Temperature (deg F)

85 105 125 85 95 105 115 125 135 0 0

10 -10

20 -20

30 -30

40 -40

50 -50

BOC

Depth (ft) Depth 60 -60 Elevation (ft) Elevation

70 -70 Measured Results 80 Model Results -80

90 -90

Tube 1 100 -100 Tube 2

110 -110 Tube 3 Bridge of Lions Concreting Curve Temperature (deg F) Temperature (deg F) 85 95 105 115 125 135 85 105 125 0 0

-10 10

-20 20

-30 30

-40 40

-50 50

BOC -60 60 Elevation (ft) Elevation Elevation (ft) Elevation

-70 70

-80 80

-90 90 Tube 1 Tube 1 Tube 2 -100 100 Tube 3 Tube 2

-110 Tube 3 110 ModeledModeled TemperatureTemperature (deg(deg F)F) Measured Temperature (deg F)

55 65 75 85 95 105 115 125 135 145 55 65 75 85 95 105 115 125 135 145 55 65 75 85 95 105 115 125 135 145 0 0 0 Sample Data Model Norm

Tube1Tube1 10 10 Tube2 Modeled Tube2 Neck Tube3 Model Tube4 Norm Tube3 Model Depth (ft) Depth Depth (ft) Depth Depth (ft) Depth (ft) 20 20 Norm Tube4Modeled Neck

30 30 Temperature (F) 100 110 120 130 140 150 160 3.00-000 1.00000 000 000 30.00 20.0000 10.0000 0.0000 -10.0000 -20.0000 -30.0000 60 70 80 90 80 70 60 50 40 30 20

4 Cage Alignment 7 10 13 16 19 62F Soil Temp

3T1 22 T3 25 28 54" excavation 54"

31 (in) Position 34 27" cage / tube diameter tube / cage 27" 37 40 43 50F Soil Temp Soil 50F 46 49 S1 S10 S19 S28 S37 S46 0 Cage Alignment WSDOT Nalley Valley I-5/SR16 WSDOT Nalley Valley I-5/SR16 Modeled and Measured Core and Tube Temps

200

180 16ft up

160 26ft up F)

(deg 140 36ft up

120 Air Temperature 100 Model ‐‐ Center 80 Model ‐‐ Cage 60 0.00 10.00 20.00 30.00 40.00 50.00 60.00 Time (hrs) Pier 6 Shaft B Temperature (deg F) Avg Field Testing Model Normal 80 90 100 110 120 130 140 150 160 T/C Data 0 Top of Perm Casing 282 5 SP - SM / SP T N 3 3 277 10 272 SM / SP T N 4 2 15 Construction Joint 267 SP - SM / SP T N 7 3 20 Bottom of Perm Casing 262 25 9' Auger w/ 1' Reamer 257 SM / SP T N 5 6 30 ) 252 SP - SM / SP T N 7 8 35 247 8' Digging Bucket w/ 2' Reamer 40

Depth (ft) Depth 242 Elevation (ft 45 10' Auger 237 50 232 SW - SM / SP T N 6 5

55 227

60 222 65 217

70 212 SM / SP T N 8 4 9' Cleanout Bucket 75 Bottom of Shaft 207 0 5 10 15 20 Temperature (deg F)

80 100 120 140 160 180 0 5 Cage Alignment 10 T1_1 15 T2_2 20 Tube Stickup 25 T3_2

30 T4_2

35 T5_2

40 T6_2 Depth (ft) Depth Water Table Sloughing 45 T7_2

50 T8_2 55 T9_2 Tube No. 6 60 T10_2 65 Average 70 Tube No. 1

75 Temperature (deg F)

80 100 120 140 160 180 0 5 Cage Alignment 10 T1_1 15 T2_2 20 NN Increasing Tube Nos. 25 25 ft T3_2

30 T4_2 TUBETUBE 11

35 T5_2

40 T6_2 Depth (ft) Depth

45 T7_2

50 T8_2 55 T9_2 125F 60 T10_2 150F 65 Average 175F 70 25 ft

75 Temperature (deg F)

80 100 120 140 160 180 0 5 Cage Alignment 10 T1_1 15 T2_2 20 NN Increasing Tube Nos. 25 T3_2

30 30 ft T4_2 TUBETUBE 11

35 T5_2

40 T6_2 Depth (ft) Depth

45 T7_2

50 T8_2 55 T9_2 125F 60 T10_2 150F 65 Average 175F 70 30 ft

75 Temperature (deg F)

80 100 120 140 160 180 0 5 Cage Alignment 10 T1_1 15 T2_2 20 NN Increasing Tube Nos. 25 T3_2

30 T4_2 TUBETUBE 11

35 35 ft T5_2 40 T6_2 Depth (ft) Depth

45 T7_2

50 T8_2 55 T9_2 125F 60 T10_2 150F 65 Average 175F 70 35 ft

75 Temperature (deg F)

80 100 120 140 160 180 0 5 Cage Alignment 10 T1_1 15 T2_2 20 NN Increasing Tube Nos. 25 T3_2

30 T4_2 TUBETUBE 11

35 T5_2

40 40 ft T6_2 Depth (ft) Depth

45 T7_2

50 T8_2 55 T9_2 125F 60 T10_2 150F 65 Average 175F 70 40 ft

75 Temperature (deg F)

80 100 120 140 160 180 0 5 Cage Alignment 10 T1_1 15 T2_2 20 NN Increasing Tube Nos. 25 T3_2

30 T4_2 TUBETUBE 11

35 T5_2

40 T6_2 Depth (ft) Depth

45 45 ft T7_2

50 T8_2 55 T9_2 125F 60 T10_2 150F 65 Average 175F 70 45 ft

75 Temperature (deg F)

80 100 120 140 160 180 0 5 Cage Alignment 10 T1_1 15 T2_2 20 NN Increasing Tube Nos. 25 T3_2

30 T4_2 TUBETUBE 11

35 T5_2

40 T6_2 Depth (ft) Depth

45 T7_2

50 50 ft T8_2 55 T9_2 125F 60 T10_2 150F 65 Average 175F 70 50 ft

75 Temperature (deg F)

80 100 120 140 160 180 0 5 Cage Alignment 10 T1_1 15 T2_2 20 NN Increasing Tube Nos. 25 T3_2

30 T4_2 TUBETUBE 11

35 T5_2

40 T6_2 Depth (ft) Depth

45 T7_2

50 T8_2 55 55 ft T9_2 125F 60 T10_2 150F 65 Average 175F 70 55 ft

75 Temperature (deg F)

80 100 120 140 160 180 0 5 Cage Alignment 10 T1_1 15 T2_2 20 NN Increasing Tube Nos. 25 T3_2

30 T4_2 TUBETUBE 11

35 T5_2

40 T6_2 Depth (ft) Depth

45 T7_2

50 T8_2 55 T9_2 125F 60 60 ft T10_2 150F 65 Average 175F 70 60 ft

75 Temperature (deg F)

80 100 120 140 160 180 0 5 Cage Alignment 10 T1_1 15 T2_2 20 NN Increasing Tube Nos. 25 T3_2

30 T4_2 TUBETUBE 11

35 T5_2

40 T6_2 Depth (ft) Depth

45 T7_2

50 T8_2 55 T9_2 125F 60 T10_2 150F 65 65 ft Average 175F 70 65 ft

75 Temperature (deg F)

80 100 120 140 160 180 0 5 Cage Alignment 10 T1_1 15 T2_2 20 NN Increasing Tube Nos. 25 T3_2

30 T4_2 TUBETUBE 11

35 T5_2

40 T6_2 Depth (ft) Depth

45 T7_2

50 T8_2 55 T9_2 125F 60 T10_2 150F 65 Average 175F 70 70 ft 70 ft 75 Cage Alignment (at 40 ft)

Depth 40 ft Worst 190 Case Cover (7.5in) 170 Highest Measured Temp

150 Lowest Measured Temp

130

110

Temperature (F) Lateral Temp Dist (model)

Cage Diameter at tubes 70 Excavation Diameter

50 -100 -80 -60 -40 -20 0 20 40 60 80 100 Horizontal Position Thermal Testing Timeframe 4000‐P Mix Design

4ft Diameter 160 6ft Diameter

8ft Diameter 140 10ft Diameter F)

(deg 120

Temperature 100

80 Optimal Testing Window Acceptable Testing Window

60 0 20 40 60 80 100 120 140 Time (hrs) 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 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. Home About FGE Services Projects Contact

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