Monitoring for Bridge Scour
Phase 3 Installation
PennDOT Technical Advisor: Paul Koza Principal Investigator: Dr. Ervin Sejdic Graduate Students: Nicholas Franconi Michael Rothfuss
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2003 – Montezuma Creek Utah 2009 – Malahide Dublin 2015 – I-10 California
What is Bridge Scour?
Introduction
Requirements
Design
Installation
Discussion
Conclusion
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Bridge Scour Assessment
Introduction
Requirements
Design
Installation
Discussion
Conclusion
Scour Code Description 8 ‐ Bridge foundations determined
to be stable for the assessed or calculated scour condition.
6 ‐ Scour calculation or evaluation has not been made
5 - Bridge foundations determined to be stable for assessed conditions
4 - Bridge foundations determined to be stable for assessed scour conditions but field review indicates action is required
3 to 0 ‐ Bridge is scour critical; bridge foundations determined to be unstable
U ‐ Bridge with unknown foundation that has not been evaluated for scour.
A bridge is classified as “structurally deficient” and in need of repair if the rating for a key structural elements is 4 or below
The National Bridge Inspection Standards require highway bridge inspections every 24 months
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In the United States… Over 200 million trips are taken daily across
structurally deficient and functionally obsolete bridges in the 102 largest metropolitan U.S. regions.
In 2013, the American Society of Civil Engineers assigned a grade of C+ to the Nation’s bridges
While conditions of bridges have steadily improved, the 2015 National Bridge Inventory reported: 58,000 structurally deficient bridges 84,000 functionally obsolete bridges
Bridge Scour Statistics
Introduction
Requirements
Design
Installation
Discussion
Conclusion
As of 2015, Pennsylvania has the 4,783 structurally deficient bridges
The FWHA estimates that to eliminate the bridge backlog by 2028, an investment of $20.5 billion would be required annually.
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Techniques for Monitoring Scour
Introduction
Requirements
Design
Installation
Discussion
Conclusion
Electrical Conductivity
Tilt Sensor
Example data from Sonar Mapping Sonar Scour Monitor Float-out Device
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Techniques for Monitoring Scour
Introduction
Requirements
Design
Installation
Discussion
Conclusion
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Introduction
Requirements
Design
Installation
Discussion
Conclusion
• Goals Mechanical and electrical float-out specifications Lifetime and indicators for RF receiver
Requirements
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Float-out and Receiver Requirements
Introduction
Requirements
Design
Installation
Discussion
Conclusion
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Float-Out Device Tilt Sensitive Activation Conforms to FCC Regulation External Magnetic Switch Unique Serial Number
RF Receiver Low Power Continuously Operating Custom Light Indicator Durable Enclosure
PennDOT Requirements
Introduction
Requirements
Design
Installation
Discussion
Conclusion
• Goals Overview of float-out electronics Float-out collision avoidance, and construction durability testing Overview of receiver electronics Receiver electronics validation
Design
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RF Receiver Design
Introduction
Requirements
Design
Installation
Discussion
Conclusion
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RF Receiver with Off-Grid Power Charge Controller
Power Consumption Calculations
Software Architecture
Receiver PCB
Float-out Device Design
Introduction
Requirements
Design
Installation
Discussion
Conclusion
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Voltage Regulator
Power Enable
RF Microcontroller
Power Amplifier
Antenna
Float-out Device Hardware Architecture
• Key Float-out Improvements Passive Reset Switch Extended 20 Year lifetime Automated false trigger reset No external reset switch
Passive Tilt Sensitive
Switch
Power Enable and Reset Circuitry
Testing of the Float-out Devices
Introduction
Requirements
Design
Installation
Discussion
Conclusion
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• Complies with FCC Regulation Maximum Transmit Power - 16.47 dBm Power Spectral Density - 6.72 dBm/3 kHz 6 dB Bandwidth - 513.25 kHz
• Collision Avoidance Algorithm Custom ALOHA NET Algorithm Transmit Period (T) of 2.5 milliseconds Pseudo-Random seeded from Serial Number
Pseudo-Random Number
Generation
Wait Pre-determined
Period of Time
Transmit Scour
Data Packet
Scour Data Packet
Bridge ID # Serial # Scour Loc. Scour Depth
Possible Float-out Devices = 216 = 65536 devices
Final Testing Procedures
Introduction
Requirements
Design
Installation
Discussion
Conclusion
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Float-Out Devices Painted and Labeled
for Installation
• Float-Out Testing Procedure Reset RF Receiver Removal of magnet to activate ARM State Tilt Float-out 90 degrees to activate ON State Verify scour indication Re-secure magnet
Introduction
Requirements
Design
Installation
Discussion
Conclusion
• Goals Receiver Installation Float-out Device Installation
Installation
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Bridge Location Information
Introduction
Requirements
Design
Installation
Discussion
Conclusion
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• Scour location Selection Process Location 1 – Significant scour present Location 2 – Significant scour present Location 3 – Scour expected to occur Location 4 – No expected scour
• PennDOT Selected Bridge Covers Pine Creek Scour present at bridge Armstrong County SR 1028 Segment 240 Bridge ID #: 03102802400395
Bridge Documentation
Introduction
Requirements
Design
Installation
Discussion
Conclusion
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Due to the age of the bridge (1923), limited documentation is available, specifically relating to the supporting structures.
Float-out Device Flush Casing Drill Rig
Introduction
Requirements
Design
Installation
Discussion
Conclusion
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Gardner Denver articulated drill rig track mount.
Articulating rig with geotechnical mast, tooling, and platform extending over the bridge
L.G. Hetager Drilling was contracted to perform the installation in November, 2015.
Installed Float-out Device Locations
Introduction
Requirements
Design
Installation
Discussion
Conclusion
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Float-out Installation Jig
Float-out Installation 1. Prepare backfill 2. Drill to 8 foot depth 3. Lift drill by 8 inches 4. Test Float-out Device 5. Lower Float-out Device 6. Hold in position with Tamper 7. Backfill appropriate quantity 8. Repeat Steps 3-7 until completed
In slow water, float-out devices remained under the bridge, however in flood conditions, the capsule should be carried downstream.
Backfill Calculations
Introduction
Requirements
Design
Installation
Discussion
Conclusion
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Antenna Orientation and Receiver Installation
Introduction
Requirements
Design
Installation
Discussion
Conclusion
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Antenna Orientation and Receiver Installation
Introduction
Requirements
Design
Installation
Discussion
Conclusion
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Antenna Selection Directional Patch Antenna Trade-offs Facing downstream for Maximum Coverage Successful communication to tree line (~500 ft.) Unable to receive signal from upstream
installation location due to antenna orientation
Distance Testing of float-out device and Antenna Orientation
LEDs visible in daylight after button press
Antenna Orientation and Receiver Installation
Introduction
Requirements
Design
Installation
Discussion
Conclusion
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Significant debris downstream cause the float-out device to be trapped in slower moving water
Float-out Installation Discussion
Introduction
Requirements
Design
Installation
Discussion
Conclusion
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The proposed scour configuration requires a total drilled depth of 8 feet. The drill time for Location 1, Location 2, and Location 4 was approximately 45 minutes. Location 3 took approximately 90 minutes to drill, due to a boulder The installation of each individual float-out device took approximately 15 minutes.
The use of multi-depth float-out devices is impractical for monitoring purposes
Float-out devices will outlast the RF receiver solar panel and battery backup system
The float-out capsules in quantity will cost under < $100/device in parts
Due to solar panel and battery, receiver is significantly more expensive ~$2,000
IoT Implementation of Bridge Monitoring
Introduction
Requirements
Design
Installation
Discussion
Conclusion
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Location 4 – Level 3Serial Number: 0x0000Depth Indicator: OrangeScour Depth: 8 FeetGPS Latitude: 40.434176GPS Longitude: -79.973581Installation Date: 09/27/2015Release Date: 09/27/2015Additional Bridges: Bridge 1 / Time 1Additional Bridges: Bridge 2 / Time 2
Birmingham BridgeLocation 1 Location 2 Location 3 Location 4
Location 4Start Scour Depth: 1 footGPS Latitude: 40.434176GPS Longitude: -79.973581
• Conceptual Map of Scour Database Bridges monitored remotely Not limited to float-out monitoring Big data processing to aide in detection Event Prediction
Introduction
Requirements
Design
Installation
Discussion
Conclusion
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• Goals Low Cost solution for monitoring scour Low maintenance Solution Designed for shallow water ways and rural bridges Improvements to the system can be made by reducing lifetime
Conclusion
Questions?
Introduction
Requirements
Design
Installation
Discussion
Conclusion
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