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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