Long-term Foundation Monitoring �and the Internet of Things

Dr. Ronaldo Luna, PE

Professor, Saint Louis University

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Presented to: TRB AKG70 Foundation Committee

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January 11, 2022

Outline

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• Foundation Monitoring for Load Transfer
• Long-term Monitoring to inform design
• Instrumentation, Monitoring and IIoT
• Closing

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A Team Effort

• Started with a curiosity, an ongoing project, and a friendship.
• Dan Brown & Associates
• FHWA Eastern Federal Lands Hwy Division
• Bell & Assoc. Construction, LP
• Corven Engineering, Inc.
• Structural Preservation Systems (GeoStructural)

Foothills Parkway - The Missing Link

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Bridge No. 2

Project Location

Subsurface Conditions

Subsurface Conditions

Piers 1 & 2

• Overburden: sandy soil mixed w/ silt and gravel
• Rock: varying layers of metaconglomerate and slate

Subsurface Stratigraphy (Siegel et al., 2010)

Bridge No. 2

Pier 1

Pier 1

Pier 2

Pier 4

Pier 3

Pier 1 – Subsurface Conditions

Slate

Phyllite

Sand

Silt and Gravel

Metaconglomerate

Meta-Sandstone Fragments

Silt, Sand, Gravel

Micropile Installation

1.

Drilling Platform

Micropile Installation (Pier 1)- Step 1a

Micropile Sub-Footing

Micropile Installation (Pier 1)- Step 1b

Central Reinforcing Bar and Strain Gage Installation

Micropile Installation (Pier 1)- Step 1c

Grouting and Bar Cutting

5.

4.

Step 2 – Pile Cap and Terminal Box

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2.

Pier 1 Pile Cap

Pier 2 Drilling Platform

Bridge Construction Process - Step 2a

Pier 1: Terminal Box Installation (pictured below)

Pier 2: Strain Gages, Central Reinforcing Bar, Framework, and Wiring Completed (not pictured)

Completed Bridge No. 2

Officially named in 2018 as the ”Dean Stone Bridge”

Data Collection During Construction

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Data Collection

Geokon Model 4999 Terminal Box

Micropile 1, Pier 1

Uphill, Micropile #1

PLAN

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4

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Construction Monitoring Results

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100% of Significant Loading

1.1%

5.8%

Construction Monitoring Results

Construction Monitoring Results

Micropile 1, Pier 1

47%

53%

Completed Bridge Load Transfer

Construction Sequence

Construction Monitoring Results

Pile Cap Poured

Column Segments Installed

Cantilever Segments Installed

Day 242: Abutment 1-Pier 1 closure joint poured

Day 280: Pier 1-Pier 2 closure joint poured

Long-term Monitoring and IIoT

Why Monitor Foundations?

• Assess load transfer during service loading
• Are any foundation elements redundant or overstressed?
• Learn and modify future design practices
• Design using side friction
• How much end bearing is really attained
• Evaluate change in loading conditions
• Earthquakes
• Landslides
• Scour

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What is IoT?

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Internet of Things

IIoT vs IoT

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What is IIoT?

• IIoT = Industrial Internet of Things

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• Currently used to monitor other industrial assets, such as in: manufacturing, oil pipelines, and electrical and waterway networks.

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• Wireless and connected sensors and gateways
• Active and passive sensors
• Access to data 24/7
• Remote data collection and dashboard display

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What is IIoT?

• We are installing an IIoT sensor network at MoDOT for other transportation assets.

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Closing

• We still do not know how efficient our foundation design is during service loading.
• We must use the latest technology to stay relevant
• New and existing bridge assets should be smarter.
• Convenience of data collection/display will enhance our understanding.

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Acknowledgements

The authors would like to acknowledge the contributions and financial support from Dan Brown & Associates, particularly Tim Siegel who participated as the foundation design engineer of for this project. Many other colleagues and engineers contributed in different parts of the project, such as Dr. Kyle Kershaw, Devin Dixon, and other individuals from the Bell & Associates Construction LP, Corven Engineering, and the owner FHWA Eastern Federal Lands Highway Division.

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Cited References

• Dixon, D. (2013). “Monitoring micropile foundations of bridge during construction.” MS thesis, Civil Engineering. Missouri University of Science and Technology, Rolla, MO.
• Kershaw, K. A. (2011). “Micropile response to combined loading” PhD thesis, Civil Engineering. Missouri University of Science and Technology, Rolla, MO.
• Siegel, T.C. and Thompson, W.R., III (2010). Foothills Parkway Bridge No. 2 Geotechnical Report. Dan Brown and Associates Consulting Geotechnical Engineers, Sequatchie, TN.
• Theinat, A. K. (2015).” 3D numerical modelling of micropiles interaction with soil & rock”. MS thesis, Missouri University of Science and Technology, Rolla, MO.

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�Thank You��Questions?�

All References

• Armour, T., Groneck, P., Keeley, J., & Sharma, S. (2000). Micropile Design and Construction Guidelines-Implementation Manual, U.S. Department of Transportation, Report FHWA-SA-97-070, Washington, D.C.
• Dixon, D. (2013). “Monitoring micropile foundations of bridge during construction.” MS thesis, Civil Engineering. Missouri University of Science and Technology, Rolla, MO.
• Ghorbani, A., Hasanzadehshooiili, H., Ghamari, E., & Medzvieckas, J. (2014). “Comprehensive three-dimensional finite element analysis, parametric study and sensitivity analysis on the seismic performance of soil–micropile-superstructure interaction”. Soil Dynamics and Earthquake Engineering, 58,21-36.
• Kershaw, K. A. (2011). “Micropile response to combined loading” PhD thesis, Civil Engineering. Missouri University of Science and Technology, Rolla, MO.
• Luna, R., Dixon, D. T., Kershaw, K. A., & Siegel, T. C. (2015). “Monitoring micropile foundations of bridge during construction.” Proc., International Foundations Congress and Equipment Expo (IFCEE) , San Antonio, 878-889.
• Misra, A. and C.-H. Chen (2004). "Analytical solution for micropile design under tension and compression." Geotechnical & Geological Engineering 22(2): 199-225.
• National Park Service (NPS) (1998). Great Smoky Mountains National Park-Foothills Parkway History. US Department of the Interior, Washington, D.C.
• Siegel, T.C. and Thompson, W.R., III (2010). Foothills Parkway Bridge No. 2 Geotechnical Report. Dan Brown and Associates Consulting Geotechnical Engineers, Sequatchie, TN.
• Theinat, A. K. (2015).” 3D numerical modelling of micropiles interaction with soil & rock”. MS thesis, Missouri University of Science and Technology, Rolla, MO.
• Wang, Z., Mei, G., Cai, G., & Yu, X. (2009). “Dynamic finite element analysis of micropile foundation in subgrade.” Recent Advancement in Soil Behavior, in Situ Test Methods, Pile Foundations, and Tunneling: Selected Papers from the 2009 GeoHunan International Conference, 139-144.

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Completed Bridge Load Transfer and Live Load Test

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Micropile 1, Pier 1

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Completed Bridge Load Transfer

87.5%

12.5%

Micropile 11, Pier 1

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Completed Bridge Load Transfer

94.1%

5.9%

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Live Load Test

Loading Configuration #1

Loading Configuration #4

Loading Configuration #3

Loading Configuration #2

Truck Setup

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Live Load Test

4 trucks

2 trucks

4 trucks

2 trucks

4 trucks

#1

#2

#3

#3

#4

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Live Load Test

#4

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#3

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#2

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#1

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Loading Configuration

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Live Load Test

#4

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#3

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#2

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#1

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Loading Configuration

Measured Live Load Compared to Measured Dead Load of Completed Bridge

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Live Load Test

Objectives:

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1. To compare the measured live loads to the measured dead load of the completed bridge

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2. Compare the measured loads at the top of the cased lengths to the top of the bond zones of the instrumented micropiles

Measured Live Load Compared to Measured Dead Load of Completed Bridge

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Live Load Test

Procedure:

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1. For the loads monitored by gages B1/2 and D1 an average was taken to obtain one average load value for all the instrumented micropiles at either the top of the casing or the top of the bond zone for each truck loading configuration

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Pier 1, Top of Casing (B1/2) Example:

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average of 01B1/2, 06B1/2, 11B1/2 and 16B1/2 for all 4 loading configurations

Measured Live Load Compared to Measured Dead Load of Completed Bridge

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Live Load Test

Procedure:

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2. The load values recorded for gages B1/2 and D1 during the completed bridge stage for all for instrumented micropiles were averaged to obtain averages of the final dead load of the bridge for the top of the casing and top of the bond zone

Pier 1, Top of Casing (B1/2) Example:

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P1P1 = 362^k

P11P1 = 101^k

P4P1 = 211^k

P16P1 = 152^k

Average = 206.5^k

Measured Live Load Compared to Measured Dead Load of Completed Bridge

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Live Load Test

% =

• Measured completed bridge load for the gages installed at level B1/2 (top of casing) at pier 1 was ≈ 94.6% greater than that of the measured load due to the applied truck loads monitored by the same pair of gages

Measured Live Load Compared to the Applied Load of the Four Trucks

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Live Load Test

Objectives:

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1. Determine how much of the live load was monitored by the instrumented micropiles

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2. Compare the top of the cased lengths to the top of the bond zones of the instrumented micropiles

Measured Live Load Compared to Measured Dead Load of Completed Bridge

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Live Load Test

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• Gages located at the top of cased lengths measured a higher

percentage of load as compared to the gages located at the top of

the bond zone

294^k