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2
Technical Report Documentation Page
1. Report No. 2. Government Accession No. 3. Recipient's Catalog No.
FHWA/OH-2014/11
4. Title and Subtitle 5. Report Date (Month and Year)
Ice Prevention or Removal on the Veterans Glass City Skyway Cables
August 2014
6. Performing Organization Code
7. Author(s) 8. Performing Organization Report No.
Douglas Nims, Victor Hunt, Arthur Helmicki, Tsun-Ming Ng
9. Performing Organization Name and Address 10. Work Unit No. (TRAIS)
University of Toledo
2801 W. Bancroft St.
Toledo, OH 43606
11. Contract or Grant No.
SJN 134489
12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered
Ohio Department of Transportation
Research Section
1980 West Broad St., MS 3280
Columbus, OH 43223
Final Report
14. Sponsoring Agency Code
15. Supplementary Notes
16. Abstract
The Veteran’s Glass City Skyway is a cable - stayed bridge in Toledo, Ohio owned by the Ohio DOT. Five times in the
seven winters the VGCS has been in service, ice has formed on the stay cables. Ice up to 3/4” thick and conforming to
the cylindrical shape of the stay has formed. As the stays warm, ice sheds in curved sheets that fall and can be blown
across the bridge. The falling ice sheets pose a potential hazard and may require lane or bridge closure.
Because of the specialized knowledge required, this problem required a team including experts in icing, the VGCS
construction, the structural measurement system on the bridge, and green technology.
The VGCS stay sheaths are made of stainless steel, have a brushed finish, lack the usual helical spiral and have a
large diameter. No existing ice anti/deicing technology was found to be practical. Therefore, ODOT elected to manage
icing administratively.
A real-time ice monitoring system for local weather conditions on the VGCS and the stays was designed. The system
collects data from sensors on the bridge and in the region. The study of the past weather and icing events lead to
quantitative guidelines about when icing accretion and shedding were likely. The monitoring system tracked the icing
conditions on the bridge with a straightforward interface so information on the icing of the bridge is available to the
bridge operators. If the conditions favorable to icing occurred, the monitoring system notified the research team and
appropriate ODOT officials. If ice has formed, the monitor tracks the conditions that might lead to ice fall.
17. Key Words 18. Distribution Statement
Ice, Bridges, Cable-stayed, Hazard Mitigation, Ice Removal, Ice Prevention
No restrictions. This document is
available to the public through the
National Technical Information Service,
Springfield, Virginia 22161
Form DOT F 1700.7 (8-72) Reproduction of completed pages authorized
19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price
Unclassified Unclassified 316 $ 652,894.58

3
Ice Prevention or Removal on the Veteran's
Glass City Skyway Cables
Prepared by:
Douglas K. Nims
Victor J. Hunt
University of Cincinnati
Arthur J. Helmicki
University of Cincinnati
Tsun-Ming T. Ng, Ph.D., P.E.
August 2014
Prepared in cooperation with the Ohio Department of Transportation
and the U.S. Department of Transportation, Federal Highway Administration
The contents of this report reflect the views of the author(s) who is (are) responsible for the facts and the
accuracy of the data presented herein. The contents do not necessarily reflect the official views or
policies of the Ohio Department of Transportation or the Federal Highway Administration. This report
does not constitute a standard, specification, or regulation.

4
Acknowledgments
The authors would like to acknowledge the University of Toledo graduate students Mr.
Ali Arbabzadegan, Mr. Joshua Belknap, Mr. Nutthavit Likitkumchorn, and Mr. Clinton
and University of Cincinnati Infrastructure Institute graduate students, Mr. Shekhar
Agrawal, Mr. Biswarup Deb, Mr. Jason Kumpf and Ms. Chandrasekar Venkatesh, who
played a significant role in the research and the writing of this report. Chapter 1,
Introduction, was primarily written by Mr. Ali Arbabzadegan with contributions from Mr.
Clinton Mirto. Chapter 3, Phase I Research, was primarily written by Mr. Arbabzadegan
with contributions from Mr. Joshua Belknap and Mr. Clinton Mirto. Chapter 4, Weather
Background, Modeling, and Analysis, was written by Mr. Belknap with contributions from
Mr. Arbabzadegan, and Mr. Mirto. Chapter 5, Development of the VGCS Dashboard
and Initial Dashboard Results was written by students from UCII. Chapter 6, New Local
Weather Sensor Testing, was written by students from UCII. Chapter 7, Experimental
Studies on the Sheath Specimens, primarily written by Mr. Arbabzadegan, Mr.
Likitkumchorn and students from UCII. Chapter 8, Deployment of New Sensors and
Upgrade of Dashboard, was written by Mr. Arbabzadegan and students from UCII.
Chapter 9, Sensor Development, was written by Mr. Likitkumchorn. Mr. Mirto assisted
in the editing of this report.
University of Cincinnati graduate students Mr. Biswarup Deb, Mr. Chandrasekar
Venkatesh, Mr. Nithyakumaran Gnanasekar, and Ms. Monisha Baskaran were
instrumental in maintaining and updating the Dashboard for this past winter and
delivering the standalone computer system to ODOT
Dr. Sridhar Viamajala graciously allowed the Scott Park Icing Experiment Station to be
built on an unoccupied portion of the concrete pad used for his sustainable energy
research.
This project was performed under the aegis of the University of Toledo – University
Transportation Center. The continuous support of Director Richard Martinko and
Associate Director Christine Lonsway has made this project possible.
The authors thank Ms. Kathleen Jones and Dr. Charles Ryerson of the U.S. Army Cold
Regions Research and Engineering Laboratory for the frequent discussions about the
project and extensive analysis, support in developing the criteria for the ice fall
dashboard, and their help in the editing of this report.
This project was sponsored and supported by the Ohio Department of Transportation.
The authors gratefully acknowledge their financial support. Mr. Mike Gramza, P.E. and
Mr. Tim Keller, P.E. were the technical liaisons and the authors appreciate their support
and input throughput the project. The author would also like to thank Mr. Mike Madry,
Mr. Dave Kanavel and Mr. Matt Harvey from ODOT for access to the bridge and
assistance in observing the icing events and Mr. Jeff Baker, P.E. (now retired from
ODOT) for his assistance in defining criteria for the ice fall dashboard and reviewing the
User Manual

5
Dedication
This report is dedicated to the late Professor K. Cyril ‘Cy’ Masiulaniec of Mechanical,
Industrial, and Manufacturing Engineering of the University of Toledo. Cy was one of
the initial investigators on this project and he was active until the week before his
passing when he developed the final details and directions for mounting the thermistors.
He will be remembered for his attention to detail and patient thorough explanations of
the thermal science that made a significant contribution to this project.
Cy was always willing to step up and help our students, his department and the college
in many ways. UT students consistently recognized him as an outstanding teacher and
he received the UT College of Engineering Award for Teaching Excellence.

6
Abstract
The Veteran’s Glass City Skyway (VGCS) is a large cable - stayed bridge in Toledo,
Ohio owned by the Ohio Department of Transportation (ODOT). The VGCS carries I-
280 over the Maumee River. Five times in the seven winters the VGCS has been in
service, ice has formed on the stay cable sheaths. Ice accumulations have been up to
approximately 3/4” thick and the ice conforms to the cylindrical shape of the stay
sheath. As the stays warm, they shed the ice in curved sheets that fall up to two
hundred and fifty feet to the roadway and the pieces of ice can be blown across several
lanes of traffic on the bridge deck. The falling ice sheets require lane closures or even
closure of the entire bridge and could present a potential hazard to the traveling public.
Because of the unique nature of the problem, the need for a quick response and the
specialized nature of the icing knowledge required, this problem has been addressed
with an expert team. The team includes experts in icing from the U.S. Army Cold
Regions Research and Engineering Laboratory and the NASA Glenn Icing Branch, the
ODOT project managers from the bridge construction, the engineers who designed and
implemented the existing structural strain measurement system on the bridge, and
experts in green technology.
The stay sheaths of the VGCS are unique: they are made of stainless steel, have a
brushed finish, lack the usual helical spiral and have a large diameter. No existing ice
anti/deicing technology was found to be practical for the VGCS. Therefore, ODOT
elected to manage icing administratively.
To do this, the research team designed a real-time monitoring system for local weather
conditions on the VGCS and the stays as well as the surrounding area. The monitoring
system collects a comprehensive set of data from local sensors on the bridge as well as
other sensors in the Toledo region. The study of the past weather and icing events lead
to quantitative guidelines about the weather conditions that made icing accretion and
shedding likely. These guidelines form the core of the algorithms in the ice monitoring
system implemented on the bridge. The monitoring system tracked the icing conditions
on the bridge with a straightforward interface so information on the icing of the bridge is
readily available to the bridge operators. If the conditions favorable to icing occurred,
the monitoring system notified the research team and appropriate ODOT officials. If ice
forms, the monitor tracks the conditions that might lead to ice fall.
The benefits of completing this project include observations of an icing event, review of
historical icing events, a building a local weather station on the bridge and stays to
collect real-time data on icing and developing the monitoring system. Because no
commercial sensor for directly measuring the presence or state of ice on the sheath
exists, an electrical resistance based sensor has been developed.

7
Table of Contents
Cover Sheet ..................................................................................................................12
Technical Report Documentation Page........................................................................... 2
Disclaimer ....................................................................................................................... 3
Acknowledgments ........................................................................................................... 4
Dedication ....................................................................................................................... 5
Abstract........................................................................................................................... 6
Table of Contents............................................................................................................7
List of Figures................................................................................................................ 12
List of Tables................................................................................................................. 19
Chapter 1: Introduction................................................................................................. 21
Section 1.1: Bridge Background ............................................................................... 21
Section 1.2: Summary of Goals and Objectives ....................................................... 24
Section 1.3: Summary of Results.............................................................................. 25
Section 1.4: Organization of this Report ................................................................... 27
Chapter 2: Goals, Objectives, Research Approach and Benefits ................................. 29
Section 2.1: Overview of Chapter ............................................................................. 29
Section 2.2: Goal ...................................................................................................... 29
Section 2.3: Objectives............................................................................................. 29
Section 2.4: Expert Team Approach to the Research............................................... 33
Section 2.5: Benefits................................................................................................. 36
Section 2.6: Chapter Summary................................................................................. 37
Chapter 3: Phase I Research ....................................................................................... 39
Section 3.1: VGCS Sheaths ..................................................................................... 39
Section 3.2: Literature Review.................................................................................. 40
Section 3.2.1 Known Icing Problems on Other Bridges.......................................... 40
Section 3.2.2 Anti-Icing/Deicing Technologies found in literature .......................... 41
Section 3.3: Technology Matrix ................................................................................ 48
Section 3.4: Sensors on the VGCS........................................................................... 50
Section 3.4.1: Sensors on the VGCS prior to the 2012 – 2013 Winter.................. 50
Section 3.4.2: Sensors added in 2012 – 2013 ....................................................... 51
Section 3.4.3: Sensors added in 2013 – 2014 ....................................................... 51
Section 3.5: Chapter Summary................................................................................. 53
Chapter 4: Weather History, Modeling and Analysis .................................................... 55

8
Section 4.1: Introduction........................................................................................... 55
Section 4.2: Description of the basic weather that gives rise to an ice storm ........... 55
Section 4.3: VGCS Weather History......................................................................... 56
Section 4.4: Lessons Learned from Previous Icing Events........................................ 73
Section 4.5: Analysis ................................................................................................ 74
Section 4.6: Chapter Summary.................................................................................. 76
Chapter 5: Development of the VGCS Dashboard and Initial Dashboard Results ....... 77
Section 5.1: Introduction............................................................................................ 77
Section 5.2: Weather Data ................................................................................... 80
Section 5.2.1: Introduction ................................................................................... 80
Section 5.2.2: Data Sources ................................................................................ 80
Section 5.2.3: Data Classification........................................................................... 83
Section 5.2.4: Data Collection and Storage .......................................................... 86
Section 5.3: Ice Accumulation Determination Algorithm ........................................... 87
Section 5.3.1: Data Update Time ........................................................................... 88
Section 5.3.2: Ice Accumulation Algorithm............................................................. 88
Section 5.3.3: Station Individual Weights.............................................................. 89
Section 5.3.4: Threshold weights ........................................................................... 90
Section 5.3.5: Ice Shedding ................................................................................... 91
Section 5.4: Ice Persistence Algorithm ...................................................................... 91
Section 5.4.1: Ice States ........................................................................................ 91
Section 5.4.2: Ice Accumulation Persistence Algorithm ......................................... 92
Section 5.4.3: Ice Presence Confirmation.............................................................. 95
Section 5.4.4: Ice Shedding Persistence Algorithm................................................ 96
Section 5.5: Monitor Website.................................................................................... 99
Section 5.5.1: Dashboard Main Panel.................................................................. 100
Section 5.5.2: Weather Map................................................................................. 101
Section 5.5.3: History........................................................................................... 103
Section 5.5.4: Implementation Tools.................................................................... 104
Section 5.6: Performance Testing ........................................................................... 104
Section 5.6.1: System Reliability Test.................................................................. 104
Section 5.6.2: Ground Truth................................................................................. 106
Section 5.7: Conclusions ........................................................................................ 125
Chapter 6: New Local Weather Sensor Testing .......................................................... 126

9
Section 6.1: Introduction.......................................................................................... 126
Section 6.1.1: Geokon Thermistors...................................................................... 126
Section 6.1.2: Dielectric Wetness Sensor ............................................................ 127
Section 6.1.3: Solar Radiation or Sunshine Sensor ............................................. 127
Section 6.1.4: Rain Tipping Bucket ...................................................................... 128
Section 6.1.5: Goodrich Ice Detector ................................................................... 128
Section 6.2: Geokon Thermistor 3800-2-2............................................................... 129
Section 6.2.1: Laboratory experiment on temperature measurement using Geokon
Thermistors .......................................................................................................... 130
Section 6.2.2: Installation of Geokon Thermistors 3800-2-2 at the VGCS on Stays 8
& 20...................................................................................................................... 135
Section 6.3: LWS-L Dielectric Leaf Wetness Sensor.............................................. 145
Section 6.3.1: Laboratory experiment on measurement of output voltage using
LWS-L Leaf Wetness Sensor............................................................................... 145
Section 6.4: Sunshine Sensor BF5.......................................................................... 149
Section 6.4.1: Laboratory experiment on measurement of solar radiation using
Sunshine Sensor BF5. ......................................................................................... 150
Section 6.5: Met One Rain Tipping Bucket.............................................................. 153
Section 6.5.1: Laboratory experiment on measurement of precipitation using
Tipping Bucket ..................................................................................................... 154
Section 6.6: Goodrich Ice Detector.......................................................................... 156
Section 6.6.1: Laboratory experiment on measurement of ice presence/thickness
using Goodrich Ice Detector 0872F1.................................................................... 157
Section 6.7: Conclusions ........................................................................................ 161
Chapter 7: Field Study of Temperature Effect on Stay Sheaths.................................. 162
Section 7.2: Design of Icing Experiment Station...................................................... 162
Section 7.3: Design of the UT Icing Tunnel and Design .......................................... 164
Section 7.4: Icing Accretion and shedding Experiments at Scott Park..................... 168
Section 7.5: Thermal Experiments at Scott Park ..................................................... 172
Section 7.6: Anti/de-icing Fluid Experiments at Scott Park...................................... 175
Section 7.7: Coating Experiments at Scott Park ...................................................... 176
Section 7.8: Coating Experiments using Icing UT Tunnel........................................ 178
Section 7.8.1: Testing Procedure ............................................................................ 178
Section 7.8.2: Experiments – Icing Progression ...................................................... 179
Section 7.8.3: Result Summery of Icing Tunnel Coating Tests................................ 199

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Section 7.9: Field Experiment Trips......................................................................... 200
Section 7.10: Conclusions ....................................................................................... 211
Chapter 8: Deployment of New Sensors and Upgrade of the Dashboard .................. 213
Section 8.2: Self Supporting Instrumentation Tower Design.................................... 213
Section 8.2.1: Tower Design ................................................................................ 213
Section 8.2.2: Anchorage System Design............................................................ 214
Section 8.3: VGCS Ice Sensors Bridge Installation trip (May 16-17, 2013) ............. 215
Section 8.4: Changes to the Ice Accumulation Algorithm ........................................ 220
Section 8.5: Changes to the Ice Shedding Algorithm............................................... 225
Section 8.6: Changes to the Dashboard.................................................................. 227
Section 8.6.1: Dashboard Main Panel.................................................................. 228
Section 8.6.2: Map (Weather Data by location).................................................... 229
Section 8.6.3: New Sensors Plotting.................................................................... 231
Section 8.7: Insights Gained from the Operation of the Upgraded Dashboard........ 235
Section 8.7.1: Ice Events (Winter 2013/2014)...................................................... 236
Section 8.7.2: Sensor Performance ..................................................................... 244
Section 8.7.3: Issues and Observations from Winter Performance...................... 249
Section 8.8: Conclusions ......................................................................................... 250
Chapter 9: Ice Presence and State Sensor Development........................................... 252
Section 9.2: Ice Presence and State Sensor Laboratory Testing ............................ 252
Section 9.2.1: Sensors and Data Acquisition System.............................................. 252
Section 9.2.2: Design of Experiments...................................................................... 254
Section 9.2.3: Laboratory Test Results.................................................................... 257
Section 9.3: UT Icing Sensor in Full Scale Experiments.......................................... 265
Section 9.3.1: Specimens and Data Acquisition System Setup............................... 266
Section 9.3.2: Full Scale Outdoor Tests .................................................................. 270
Section 9.3.3 Full Scale Experiments Result ........................................................... 272
Section 9.4: Conclusion and Next Steps.................................................................. 275
Chapter 10: Transition and Maintenance .................................................................... 276
Section 10.1: Introduction....................................................................................... 276
Section 10.2: Standalone Computer System......................................................... 276
Section 10.3: Maintenance ...................................................................................... 276

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Chapter 11: Conclusion, Benefits, Implementation and Future Work.......................... 279
Section 11.1: Summary of Goals and Objectives .................................................... 279
Section 11.2: Results............................................................................................... 280
Section 11.3 Benefits............................................................................................... 284
Section 11.4: Implementation .................................................................................. 285
Section 11.5: Transition and Long Term Maintenance ............................................ 286
Section 11.6: Archiving of Supporting Documents................................................... 286
Section 11.7: Recommendations for Future Work ................................................... 286
Bibliography ................................................................................................................ 289
Appendix A: Technology Matrix................................................................................... 306

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List of Figures
Figure 1: Veteran’s Glass City Skyway (photo credit will be provided).......................... 21
Figure 2: Veteran’ Glass City Skyway’s Illuminated Glass Pylon (ODOT, 2010) ........... 22
Figure 3: Ice Accumulation on the East Side of VGCS (Baker, 2007) ........................... 23
Figure 4: Ice on the Pylon and the VGCS Glass ........................................................... 23
Figure 5: Large Piece of Ice Almost Hitting a Car.......................................................... 24
Figure 6: Application of Superhydrophobic Coating on the Surface (Ryerson, 2008) ... 42
Figure 7: DC Bias Deicing where Electrolysis forms Bubbles (Ryerson, 2008)............. 43
Figure 8: Pulse Electro Thermal Deicing (PETD) (Ryerson, 2008) ............................... 44
Figure 9: Ice Being Released using Ice Dielectric Heating (Ryerson, 2008) ................. 44
Figure 10: Navy Vertical Launch Systems with Electrically Heated Door Edges
(Ryerson, 2008) ............................................................................................................ 45
Figure 11: Infrared Heaters above the CRREL Entrance (Ryerson, 2008).................... 46
Figure 12: Aviation Facility using Infrared Radiant System (Ryerson, 2008)................. 46
Figure 13: Photonic Deicer for Deicing of Power Lines (Couture, 2011) ....................... 48
Figure 14: Damaging ice storm footprint map, 1946-2014 in the lower 48 states and
portions of the lower tier of Canada............................................................................... 56
Figure 15: Dashboard readout for February 21, 2011 ................................................... 59
Figure 16: Overview of ice accreting on stay at 10:29 PM Sunday evening.................. 60
Figure 17: Close up of ice accreting on stay at 10:29 PM Sunday evening................... 60
Figure 18: Stay cable diagram with ice accumulation.................................................... 61
Figure 19: Ice Accumulation up east side of stay February 22, 2011............................ 63
Figure 20: Frozen Rivulets and bare metal on the west side of stays February 22, 2011
...................................................................................................................................... 63
Figure 21: Thermocouple reading between ice and stay February 23, 2011................. 64
Figure 22: Thermocouple reading between the ice and stay February 24, 2011........... 65
Figure 23: Cracking in ice from chipping away ice, February 23, 2011 ......................... 66
Figure 24: Section where ice was chipped away to take temperature readings February
23, 2011 ........................................................................................................................ 67
Figure 25: Ice thickness measurements on back stay 19 February 23, 2011................ 67
Figure 26: Ice thickness measurements on back stay 19 February 23, 2011................ 68
Figure 27: Ice accumulation on pylon glazing February 24, 2011 ................................. 69
Figure 28: Ice on bridge deck after 80-90% had shed, February 24, 2011.................... 69
Figure 29: Weather Summary for the week of February 20, 2011 (Weather
Underground, 2011) ...................................................................................................... 71
Figure 30: Solar radiation counts February 22, 2011 .................................................... 72
Figure 33: Process Flow Diagram ................................................................................. 79
Figure 34: Map Showing Distances of Weather Stations from VGCS ........................... 83
Figure 35: Ice Determination Algorithm......................................................................... 89
Figure 36: Dashboard Speedometer ............................................................................. 91
Figure 37: Ice Accumulation Flowchart ......................................................................... 93
Figure 38: Sample Ice Accumulation Message Alert..................................................... 94
Figure 39: Dashboard with Ice Accumulation Alert........................................................ 95
Figure 40: Ice Presence Flowchart................................................................................ 95

13
Figure 41: Ice Shedding Flowchart................................................................................ 97
Figure 42: Sample Ice Shedding Message Alert ........................................................... 98
Figure 43: Dashboard with Ice Shedding Alert.............................................................. 99
Figure 44: State Transitions possible from Red Level 3................................................ 99
Figure 45: Dashboard Main Panel............................................................................... 101
Figure 46: Dashboard History Panel ........................................................................... 103
Figure 47: Weather Summary on Feb 20, 2011 .......................................................... 107
Figure 48: Screenshot Showing Ice Accretion on VGCS............................................. 108
Figure 51: Ice Accumulation on Stays on Feb 22, 2011.............................................. 110
Figure 53: Example of Ice Shedding Alert................................................................... 112
Figure 54: Ice Falling from VGCS on Feb 24, 2011 ................................................... 113
Figure 56: Feb 24, 2011 Algorithm Performance Graph.............................................. 115
Figure 57 : Contribution of the Icing Criteria and Weather Stations ............................ 116
Figure 58: Solar Radiation Variation on Feb 24, 2011 ................................................ 117
Figure 59: Features of the Past Icing Events .............................................................. 119
Figure 60: Dec 12, 2007 Algorithm Performance Graph ............................................. 120
Figure 61: Mar 28, 2008 Algorithm Performance Graph.............................................. 122
Figure 62: Dec 17, 2008 Algorithm Performance Graph ............................................. 123
Figure 63: Jan 03, 2009 Algorithm Performance Graph.............................................. 124
Figure 64: Geokon 3800-2-2 Thermistor ..................................................................... 130
Figure 65: Naked Thermistor Bead (photo credits, John Flynn, Geokon Inc.)............. 130
Figure 66: Canary Systems Multilogger Software ....................................................... 131
Figure 67: Measurement trend of eight thermistors..................................................... 132
Figure 68: Thermistors kept in freezer......................................................................... 133
Figure 69: Thermistors immersed in water left to freeze ............................................. 133
Figure 70: Readings simultaneously noted by handheld GK 404................................ 133
Figure 71: Standard thermometer immersed in setup to record temperature.............. 133
Figure 72: Thermistor Characteristics at Freezing ...................................................... 134
Figure 73: Side View of Gage Locations at VGCS ...................................................... 135
Figure 74: Custon Thermistor Mount Fabricated for Installing on Stay Surface .......... 136
Figure 75: Thermistor Placed on East Side of Stay..................................................... 136
Figure 76: Thermistors Placed on Upper Side of Stay ................................................ 136
Figure 77: Far View of Thermistor Installation of Stay................................................. 137
Figure 78: Thermistor Cables Being Routed to Multiplexer Inside White Box ............. 137
Figure 79: Stay Sheath Cross Section Showing Thermistor Positions ........................ 138
Figure 80: Stay 20 Thermistors Temperature Trend ................................................... 139
Figure 81: Stay 8 Thermistors Temperature Trend ..................................................... 140
Figure 82: Characteristics for Stay 20 Thermistors on March 15 ................................ 143
Figure 83: Characteristics for Stay 20 thermistors on March 9 & 10 ........................... 144
Figure 84: Leaf Wetness Sensor functional diagram................................................... 145
Figure 85: Experimental setup of data logger CR1000 with LWS-L Leaf Wetness Sensor
.................................................................................................................................... 146

14
Figure 86: Droplets of Water Sprinkled on Leaf .......................................................... 146
Figure 87: LWS-L partially immersed in cup of water.................................................. 147
Figure 88: LWS-L immersed in cup left to freeze ........................................................ 147
Figure 89: LWS Wetness Test .................................................................................... 148
Figure 90: LWS Freezing Temperature Test............................................................... 148
Figure 91: Sunshine Sensor BF5 (side view) and Detailed Construction .................... 149
Figure 92: Sunshine Sensor BF5 Set Up on a Deck for Unobstructed Exposure to Solar
Radiation.....................................................................................................................150
Figure 93: Solar radiation characteristics over an extended period of 16 days ........... 151
Figure 94: A typical partly cloudy day chosen to see the daily solar radiation
characteristics ............................................................................................................. 152
Figure 95: A typical clear sunny day taken as example to see the daily solar radiation
characteristics ............................................................................................................. 153
Figure 96: Rain Tipping Bucket (from top left clockwise) distant view, top view and
inside view................................................................................................................... 154
Figure 97: Rain Bucket lab.......................................................................................... 155
Figure 98: Gessler Buret ............................................................................................. 155
Figure 99: Rain Bucket accuracy experiment (actual vs tipping volume) .................... 156
Figure 100: The Goodrich Ice Detector (external and function diagrams)................... 157
Figure 101: Ice Detector Mounted for Experiment....................................................... 159
Figure 102: Microcare Anti-Stat Freezing Spray ......................................................... 159
Figure 103: Probe before Spraying ............................................................................. 159
Figure 104: Probe After Spraying................................................................................ 159
Figure 105: Frequency/Ice thickness characteristics of 0872F1 during freezing spray
experiment .................................................................................................................. 160
Figure 106: Thickness measurement using calipers ................................................... 160
Figure 107: Google Earth Screenshot of Scott Park ................................................... 162
Figure 108: Experimental Setup.................................................................................. 163
Figure 109: Sensors on South-faced Specimen.......................................................... 164
Figure 110: Data Acquisition System .......................................................................... 164
Figure 111: SolidWorks Design for the UT Icing Tunnel.............................................. 165
Figure 112: UT Icing Tunnel........................................................................................ 165
Figure 113: Testing Section of the UT Icing Tunnel .................................................... 166
Figure 114: Misting System in the Testing Section ..................................................... 167
Figure 115: Panasonic HX_A100D Camera (Panasonic 2013)................................... 167
Figure 116: Mounting System of Testing Section........................................................ 168
Figure 117: Spraying a Mist of Water on North-faced Specimen ................................ 168
Figure 118: Pattern of Ice Accumulation on Outdoor Tests......................................... 169
Figure 119: Water beneath the Ice Layer before Shedding......................................... 169
Figure 120: Ice Shedding Steps .................................................................................. 170
Figure 121: Stay’s Behavior in Icing Test – 2/15 to 2/18 ............................................. 171
Figure 122: Stay’s Behavior in Icing Test – 2/20 to 2/22 ............................................. 171
Figure 123: Thermal Experiment Setup....................................................................... 173
Figure 124: Strands Configuration in Thermal Tests................................................... 173
Figure 125: Deicing Pattern in Thermal Test............................................................... 174
Figure 126: Accumulated Ice in Anti-icing Thermal Test ............................................. 174

15
Figure 127: Formation of Ice in Chemical Anti-icing Test............................................ 175
Figure 128: Drip Tube System used in Chemical Deicing Test ................................... 176
Figure 129: Hydrobead Sprayed on Half of the Specimen .......................................... 177
Figure 130: Water Droplets due to Hydrobead............................................................ 177
Figure 131: Specimen’s Behavior in Coating Test ...................................................... 178
Figure 132: Uncoated - 40 Micron - 0:00 min.............................................................. 179
Figure 136: Uncoated - 40 Micron – 1:00 min ............................................................. 180
Figure 142: Uncoated - 40 Micron – 10:00 min ........................................................... 182
Figure 143: Uncoated - 40 Micron – After Test ........................................................... 183
Figure 144: None Coating - 40 Micron – Shed Ice Sheet............................................ 183
Figure 145: Hydrobead-Coated Specimen.................................................................. 184
Figure 146: Hydrobead – 40 Micron – 0:00 min .......................................................... 184
Figure 156: Hydrobead – 40 Micron – 10:00 min ........................................................ 188
Figure 157: Hydrobead – 40 Micron – After Test ........................................................ 188
Figure 158: Hydrobead – 40 Micron – Shed Ice Sheet................................................ 189
Figure 159: PhaseBreak TP – 40 Micron – 0:00 min................................................... 189
Figure 165: PhaseBreak TP – 40 Micron – 2:00 ......................................................... 191
Figure 169: PhaseBreak TP – 40 Micron – 10:00 ....................................................... 193
Figure 170: PhaseBreak TP – 40 Micron – After Test................................................. 193
Figure 171: PhaseBreak TP – 40 Micron – Shed Ice Sheet........................................ 194
Figure 172: WeatherTITE – 40 Micron – 0:00 min ...................................................... 194

16
Figure 183: WeatherTITE – 40 Micron – 10:00 min .................................................... 198
Figure 184: WeatherTITE – 40 Micron – After Test..................................................... 198
Figure 185: WeatherTITE – 40 Micron – Shed Ice Sheet............................................ 199
Figure 186: Stay Specimens at Different Angles and Orientations.............................. 201
Figure 187: Data-logging System Setup...................................................................... 201
Figure 188: Sunshine Sensor Setup............................................................................ 201
Figure 189: Ice Detector Placed Right Beside Stay .................................................... 201
Figure 190: Stay Thermistors Zip-tied on Sheath........................................................ 201
Figure 191: Leaf Wetness Sensor Taped on top of Specimen.................................... 201
Figure 192: Ice Detector at Various Times Throughout the February 16 Experiment . 202
Figure 193: Leaf Wetness Sensor at Various Times Throughout the February 16
Experiment.................................................................................................................. 203
Figure 194: Ice Detector Characteristics (Toledo experiments on February 16) ......... 204
Figure 195: Characteristics of stay thermistors (Toledo, February 16)........................ 205
Figure 196: Leaf Wetness Sensor ice melting characteristics..................................... 205
Figure 197: LWS-LS with Different Slants................................................................... 207
Figure 198: Top & Side Thermistors Setup ................................................................. 207
Figure 199: Ice Detector Setup ................................................................................... 207
Figure 200: First Spray Shower................................................................................... 207
Figure 201: Garden Hose mount on ladder (left) & hand held (right) for experiment on
ice detector & leaf sensors.......................................................................................... 208
Figure 202: Ice Detector at Various Times during Experiment (Left and Middle during ice
accretion; right during deicing) .................................................................................... 208
Figure 203: Stay thermistor characteristics (Toledo experiments February 20 – 21) .. 209
Figure 204: Leaf Wetness Sensor Characteristics (Toledo, February 20 – 21)........... 210
Figure 205: Ice Detector characteristics (Toledo, February 20 – 21) .......................... 211
Figure 206: Tower Anchorage System........................................................................ 214
Figure 207: Rohn’s Weather Tower Drawing .............................................................. 215
Figure 208: Tower mounted near stay 19.................................................................... 215
Figure 209: Initial Plan by UT Research Team for Tower Mounting............................ 216
Figure 210: Leaf Wetness Sensor Zip-tied to Cross-arm ............................................ 217
Figure 211: Rain Bucket mounted on cross-arm using leveling bracket...................... 218
Figure 212: Sunshine Sensor attached to cross-arm with steel U-bolts ...................... 218
Figure 213: Ice Detector Mounted using Steal Worm Band Clamps ........................... 219
Figure 214: Ice Detector Mounted Close Up ............................................................... 219
Figure 215: Sensor Cable Conduit .............................................................................. 219

17
Figure 216: CR1000 Datalogger Setup Insider Tower Cabinet ................................... 219
Figure 217: Close up of Weather Tower...................................................................... 220
Figure 218: Completed New Weather Station Near Stay 19 ....................................... 220
Figure 219: Flowchart of existing Ice Accumulation Algorithm (Agrawal, 2011).......... 222
Figure 220: Flowchart for revised ice accumulation algorithm..................................... 224
Figure 221: Flowchart of existing Ice Shedding Algorithm (Agrawal, 2011) ................ 226
Figure 222: Flowchart for revised ice shedding algorithm ........................................... 227
Figure 223: Dashboard Main Panel............................................................................. 228
Figure 224: Example Snapshot of Weather Map, with Pop-up for Ice Detector .......... 230
Figure 225: Last 48 hour report of Solar Sensor (Global Radiation) ........................... 231
Figure 226: Last 48 hour report of Leaf Wetness Sensor............................................ 231
Figure 227: Stay 20 Thermistors plot (January 1 – July 1).......................................... 232
Figure 228: Stay 8 Thermistors plot (January 1 – July 1)............................................ 232
Figure 229: Ice Detector plot (June 1 – July 1)............................................................ 233
Figure 230: Leaf Wetness Sensor plot (June 1 – July 1)............................................. 233
Figure 231: Rain Tipping Bucket plot (June 1 – July 1)............................................... 234
Figure 232: Sunshine Sensor plot (June 1 – July 1).................................................... 234
Figure 233: Ice Detector & LWS Characteristics during Ice Event, December 9, 2013237
Figure 234: VGCS Icing camera view before noon ..................................................... 239
Figure 235: Ice Detector & Leaf Wetness Sensor characteristics on February 20 ...... 240
Figure 236: Ice detector & Leaf wetness Sensor characteristics on April 3................. 242
Figure 237: Rain Tipping Bucket & Leaf Wetness Sensor characteristics on April 3... 242
Figure 238: Solar Radiation & Stay Thermistor 8X08TWS characteristics on April 3.. 243
Figure 239: Leaf Wetness Sensor characteristics winter 2013/14............................... 245
Figure 240: Stay Thermistor characteristics winter 2013/14........................................ 245
Figure 241: Sheath thermistors warming faster than outer (March 4, 2014) ............... 246
Figure 242: Rain Tipping Bucket characteristics winter 2013/14................................. 247
Figure 243: Ice Detector characteristics winter 2013/14.............................................. 248
Figure 244: Solar radiation Sensor characteristics winter 2013/14 ............................. 249
Figure 245: Relative distribution of alarms triggered by new sensors ......................... 249
Figure 246: UT Icing Sensor Circuit ............................................................................ 253
Figure 247: Electro Spacing Area of the UT Icing Sensor........................................... 253
Figure 248: UT Icing Sensor Connected to Data Acquisition System ......................... 254
Figure 249: Dashboard of UT Icing Sensor................................................................. 254
Figure 250: 1-mm Electro Spacing UT Icing Sensor ................................................... 255
Figure 251: 7-mm Electro Spacing UT Icing Sensor ................................................... 255
Figure 252: Water Measurement................................................................................. 256
Figure 253: Ice Measurement ..................................................................................... 256
Figure 254: 75% Slush Measurement ......................................................................... 256
Figure 257: Ice Measurement at 6 mm thickness........................................................ 257
Figure 258: Ice Measurement at 13 mm thickness...................................................... 257
Figure 259: Ice Measurement at 19 mm thickness...................................................... 257
Figure 260: Resistance of Ice for 1-mm Electro Spacing Sensor ................................ 258
Figure 261: Dashboard Screenshot of Ice Measurement............................................ 258

18
Figure 262: Resistance of 75% Slush for 1-mm Electro Spacing Sensor.................... 259
Figure 263: Dashboard Screenshot of 75% Slush Measurement................................ 259
Figure 266: Resistance of 25% Slush for 1-mm Electrode Spacing Sensor................ 261
Figure 268: Resistance of Water for 1-mm Electro Spacing Sensor ........................... 262
Figure 269: Dashboard Screenshot of Water Measurement ....................................... 262
Figure 270: Resistance of Ice for 7-mm Electro Spacing Sensor ................................ 263
Figure 274: Resistance of Water for 7-mm Electro Spacing Sensor ........................... 264
Figure 275: Resistances for 6-mm Thickness and 7-mm Electro Spacing Sensor...... 265
Figure 276: VGCS Stainless Steel Specimens............................................................ 266
Figure 277: HDPE Specimen and Frame Structure .................................................... 266
Figure 278: North Facing Specimen with 120 Stands Inside....................................... 267
Figure 279: Sensors Setup on VGCS Specimen......................................................... 268
Figure 280: Sensors Setup on HDPE Specimen......................................................... 268
Figure 281: Cross Section and Sensor Setup Orientation of both Specimens ............ 268
Figure 282: UT Icing Sensor on HDPE Specimen....................................................... 268
Figure 283: MicroStrain V-Link.................................................................................... 269
Figure 284: MicroStrain TC-Link ................................................................................. 269
Figure 285: MicroStrain WSDA-Base (Signal Receiver).............................................. 270
Figure 286: V-Link and UT Icing Sensor ..................................................................... 271
Figure 287: Ice Testing................................................................................................ 271
Figure 288: Slush Testing ........................................................................................... 271
Figure 289: Water Testing........................................................................................... 271
Figure 290: UT Icing Sensor Initial Test ...................................................................... 272
Figure 291: Misting Water on VGCS Specimen .......................................................... 273
Figure 292: Ice Accumulation on VGCS Specimen..................................................... 273
Figure 293: Stay Behavior in Icing Experiment ........................................................... 274
Figure 294: Flowchart for Stand Alone System........................................................... 278

19
List of Tables
Table 1: Viable Technologies........................................................................................ 31
Table 2: Information Required to Revolve Uncertainties ............................................... 31
Table 3: Team Members Roles and Expertise .............................................................. 35
Table 4: Sheath Roughness Test Data ......................................................................... 40
Table 5: Most Viable Solutions for the VGCS................................................................ 50
Table 6: Uncertainties that Needed Resolved and Corresponding Sensors.................. 52
Table 7: Ice Accumulation Weather Conditions............................................................. 56
Table 8: Ice Falling Weather Conditions........................................................................ 57
Table 9 Weather Conditions for February 20, 2011 (Kumpf et. al, Weather Underground,
2011)............................................................................................................................. 61
Table 10: Interstice Temperature February 23.............................................................. 65
Table 11: Weather conditions for February 24, 2011 (Kumpf et. al, Weather
Underground , 2011) ..................................................................................................... 68
Table 12: Ice Accumulation Criteria .............................................................................. 74
Table 13: Ice Fall Criteria .............................................................................................. 74
Table 14: Sensor System at RWIS Stations.................................................................. 81
Table 15: Airport Information......................................................................................... 82
Table 16: Distances of Weather Stations from VGCS................................................... 83
Table 17: METAR and RWIS Precipitation Measurements for Ice Accumulation.......... 84
Table 18: Ice Accumulation Criteria .............................................................................. 85
Table 19: METAR and RWIS Precipitation Measurements for Ice Shedding ................ 85
Table 20: Ice Shedding Criteria..................................................................................... 86
Table 21: Final Ice Accumulation/Shedding Criteria...................................................... 86
Table 22: Weather Station Weights............................................................................... 89
Table 23: Dial States Explanation ................................................................................. 92
Table 24: Tools Used To Design Dashboard .............................................................. 104
Table 25: Dates for Past Ice Events that were Tested ................................................ 105
Table 26:Weather Statistics for December 12, 2007 Ice Event................................... 105
Table 27: Summary of Events when Ice Accumulation occurred in 2011.................... 106
Table 28: Interstice Temperature on February 23, 2011 ............................................. 111
Table 29: Station Comparison for the 2011 Winter ..................................................... 116
Table 30: Overall Performance of Dashboard on Past Icing Events ........................... 124
Table 31: Comparison of readings taken by all 3 methods.......................................... 133
Table 32: New Stay Thermistors List........................................................................... 138
Table 33: Sky Cover and Precipitation During the Period ........................................... 141
Table 34: Weather Report on March 15 ...................................................................... 142
Table 35: Wetness Test .............................................................................................. 146
Table 36: Impurity Test................................................................................................ 147
Table 37: Impurity Test................................................................................................ 147
Table 38: Rain Bucket Lab Experiment 1 with 5 Minute Sampling Rate...................... 155
Table 39: Rain Bucket Lab Experiment 2 with 30 Minute Sampling Rate.................... 156
Table 40: Caliper Test................................................................................................. 160
Table 41: Icing Sensors Initial Observations ............................................................... 161
Table 42: Approximated ice thickness comparison of coatings and droplet sizes....... 199
Table 43: Event History (February 16, 2013) .............................................................. 200

20
Table 44: Event History (February 20-21, 2013) ......................................................... 206
Table 45: Summary of VGCS Sensor Installation Trip ................................................ 217
Table 46: Ice Accumulation Station Functions ............................................................ 223
Table 47: Ice Fall Station Functions in algorithm......................................................... 226
Table 48: Chronology of winter 2013/2014 icing event triggers................................... 236
Table 49: Web Report Tool: Sample Icing Events and Comments, December 2013 .. 243

Chapte
Section
The Vete
Crossing
River in
and is co
2013). T
2007. T
span is a
above th
VGCS, w
develop
The VGC
steel sta
installati
need for
to the ot
convent
that is in
below. T
local eve

er 1: Intr
n 1.1: Bridg
eran’s Glas
g is a large
Toledo, Oh
onsidered a
The constru
The entire p
approximat
he bridge de
which is an
ment, carrie
Figure
CS has sev
ay sheathes
ons of a ne
r cable anch
ther. This a
ional ancho
nfinitely vari
This makes
ents or the
roduction
ge Backgro
ss City Skyw
cable-staye
hio. The VG
as the most
uction bega
roject cons
tely 1,225-fe
eck, and ha
important c
es three lan
e 1: Veteran’s
veral novel f
s, and the il
ew cradle sy
horage in th
llows the to
orage arran
able, an ex
the pylon v
time of the
n
ound
way (VGCS
ed bridge o
GCS is owne
t expensive
an in 2001 a
ists of 8,80
eet in lengt
as a single
connector f
nes of traffic
s Glass City
features: th
luminated g
ystem (Figg
he pylon by
ower to be m
gement. Th
xample of o
visible for m
year.
21
S), formerly
on Interstate
ed by the O
e project eve
and the brid
00 feet of ap
h, consists
plane of sta
for multimod
c and has th
Skyway (pho
he cradle sy
glass in the
g, 2005). T
y carrying st
more slende
he pylon is
ne lighting
miles at nigh
known as t
e 280 that c
Ohio Depart
er undertak
dge was ope
pproaches a
of a single
ays, seen in
dal transpo
housands o
oto credit wi
ystem for th
e pylon. The
This particul
tays from o
er than wha
illuminated
schemes c
ht and the p
the Maume
crosses ove
tment of Tra
ken by ODO
ened for se
and main s
pylon that
n Figure 1 b
ortation and
of vehicles c
ill be provide
he stays, the
e VGCS is o
ar system e
one side of t
at is possib
with intern
can be seen
pylon can be
ee River
er the Maum
ansportatio
OT (Wikiped
ervice in Jul
pan. The m
rises 216 fe
below. The
economic
crossing da
ed)
e stainless
one of two
eliminates t
the bridge d
le with a
al LED ligh
n in Figure 2
e lit to reflec
mee
n
dia,
y
main
eet
e
aily.
the
deck
ting
2
ct

Under so
accumu
then she
stay can
tempera
the road
lanes of
and falle
closure f
to the tra
to motor
presenc
Figures
event.
Figure 2: V
ome winter
lation can e
eds in semi-
n occur in le
atures and s
dway. Due
traffic. In s
en in the riv
for the dura
aveling pub
rists and de
e is determ
3 and 4 sho
Veteran’ Glas
r conditions
exceed a 1/
-cylindrical
ess than a m
solar radiati
to their aer
some instan
er. The po
ation of the
blic as well a
etermining ic
mined manu
ow ice accu
ss City Skyw
, ice forms
/2 inch and
sheets from
minute. Ice
ion. The sh
odynamic s
nces, large
tential of fa
ice persiste
as loss to e
ce presenc
ally, putting
umulation o
22
way’s Illumina
on the stay
may persis
m the cable
e shedding i
eets may fa
shape, they
ice sheets
alling sheets
ence. Lane
economic ac
e remotely
g ODOT pe
on the stays
ated Glass P
y cables of t
st for severa
e sheaths. S
is triggered
all over two
y can glide o
have cross
s typically re
closures re
ctivities. Fa
is problem
rsonnel in h
s and pylon
Pylon (ODOT,
the VGCS.
al days on t
Shedding o
by a comb
o hundred a
or be blown
sed all the la
equires lan
esult in the
alling ice is a
atic. Curren
harm’s way
of VGCS in
T, 2010)
Ice
the stays. Ic
of an individ
bination of r
and fifty feet
n across se
anes of traf
e or bridge
inconvenie
a safety haz
ntly, ice
y.
n the 2011
ce
dual
ising
t to
veral
ffic
nce
zard
icing

Figure 5
circled in
bridge (B
Figur
5, which was
n red, falling
Belknap, 20
re 3: Ice Accu
Figure
s captured
g into the th
011).
umulation on
4: Ice on the
during 201
hird lane of
23
n the East Si
e Pylon and t
1 ice fall ev
traffic while
ide of VGCS
the VGCS Gl
vent, shows
e vehicles a
(Baker, 2007
ass
s a large pie
are still trav

7)

ece of ice,
velling over the

Section
After fou
was und
VGCS.
available
the pote
impleme
The first
 Id
ic
 A
 E
te
 F
d
b
 D
re
im
As the p
develope
knowled
address
The Fina
n 1.2: Sum
ur icing eve
dertaken to
The resear
e technolog
ential techno
entation of a
t phase obje
dentify avai
cing problem
Assess the s
Examine the
echnology o
For each via
efine requir
udget for im
Develop a re
esearch tea
mmediately
project prog
ed in the fir
dge gained
the need to
al Phase II
Figure 5
mary of Go
nts in the fi
assist ODO
rch followed
gies, selecti
ologies whe
a monitoring
ectives wer
lable techn
m.
state of the
e advantage
on the VGC
able solutio
red validati
mplementat
eal-time icin
am in respo
y actionable
ressed, as
rst phase. T
concerning
o better und
objectives w
5: Large Piec
oals and O
rst two wint
OT in implem
d a phased
on of poten
ereas the se
g system a
re:
ologies and
art via liter
es, disadva
CS.
n, develop
on testing,
tion and de
ng condition
onse to a re
e by the brid
phase II wa
The objectiv
the state o
derstand th
were:
24
ce of Ice Alm
Objectives
ter seasons
menting an
approach.
ntial techno
econd phas
nd sensors
d procedure
rature review
ntages, and
a detailed d
perform a b
efine a time
n monitor. T
equest by O
dge operato
as undertak
ves for Pha
of the art an
e microclim
ost Hitting a
s of the VGC
icing mana
The first p
logies for th
se focused
s.
es that coul
w and cons
d applicabil
description
benefit/cos
frame for i
This object
ODOT to ma
ors.
ken. Phase
ase II altere
nd practice
mate on the
a Car
CS being o
agement pr
phase focus
he VGCS a
on the deve
ld potentiall
sultation wit
lity of each
of the impl
t analysis,
mplementa
ive was add
ake the rese
e II built on
ed to accoun
in anti/deic
bridge.

open, resea
rocedure fo
sed on revie
and costing
elopment a
ly solve the
th icing exp
identified
lementation
develop a
ation.
ded by the
earch
the backgro
nt for the
ing and to
arch
r the
ew of
of
and
e
perts.
n,
ound

25
 Collect data to resolve uncertainties in the bridge microclimate and the conditions
on the stays. To understand the icing behavior it was necessary to gain
knowledge about how and when ice was forming on the stays, stay sheath
temperatures and the local conditions on the bridge,
 Make a recommendation on two to four viable active solutions. This required
experiments on anti/deicing techniques as well as literature review and
discussion with experts.
 Improve the user friendliness, algorithms and error handling of the icing monitor.
 Develop of an ice presence and state sensor. No such commercial senor exists
and data about the ice persistence and water flow beneath the ice is essential to
understanding shedding.
Through experimentation, no practical active or passive anti/deicing solution was ever
identified, as discussed in Chapter 7 of this report. This ultimately led to a new overall
objective, which was to improve the monitoring of icing events in order to provide ODOT
with the best information to manage their response to an icing event.
The goals, objectives, and uncertainties will be provided in more detail in the following
chapter.
Section 1.3: Summary of Results
Past icing events were reviewed, the mechanisms for icing where explored, and the
basic conditions that are favorable to icing accretion and shedding were ascertained.
Historically, roughly two icing events occur each year. Icing on the VGCS occurs when
there is general icing in the area. There have been five major icing events on the VGCS.
The last of which was in February 2011.
Conditions are favorable for ice accretion when one of the following conditions occurs:
i. Precipitation with air temperature at the bridge below 32o
F, or
ii. Fog with air temperature at the bridge below 32o
F, or
iii. Snow with air temperature at the bridge above 32o
F.
The ice accretion rate is generally slow because during an ice storm precipitation rates
are low and much of the water runs off the stays. Once the ice accretes on the stays
and pylon, it may persist until shedding conditions occur. Temperatures above 32o
F
and/or solar radiation cause ice fall. Water flowing beneath the ice layer was observed
prior to the ice fall in 2011 and is thought to be a precursor to ice fall. If there is ice on
the stay, the weather conditions that cause ice fall are:
i. Air temperature above 32o
F (warm air), or
ii. Clear sky during daylight (solar radiation).
Given the unique features of the VGCS, the paucity of literature directly on point, and
the urgency of addressing the problem, an expert team was selected to address this
problem. The research team that had expertise in icing, icing instrumentation, icing test
facilities, the VGCS construction and VGCS instrumentation was formed to address the

26
issues of ice prevention and mitigation on the VGCS.
A comprehensive review all anti/deicing technologies that could be identified regardless
of their technology readiness level was performed. A matrix of over 70 potential
technologies was developed. The matrix describes the advantages and disadvantages
of each technology. To simulate icing events and use a test bed for experiments an
icing field station was designed and built. It had three full scale sheath specimens ten
feet long. One of these specimens included strand. The station had a local weather
station and a wireless data acquisition. The initial set of experiments verified that ice
accretion and shedding similar to that which occurs on the bridge could be replicated.
The icing station was then used for experiments on anti/decing chemicals, anti-icing
coating, heat for anti-icing and deicing, and tests of instruments.
The technologies that were the most viable were identified. They were:
i. Deicing/anti-icing chemicals which would not present a biohazard when
leached into the river such a sodium chloride; agricultural products, such as
beet based deicers, and calcium chloride
ii. Anti-icing coatings
iii. Heat. The VGCS stays are mostly hollow so there is a potential to internally
heat the stays.
Experiments to evaluate the efficacy of each viable technology were carried out. The
anti-icing chemical experiments showed that on the stainless steel surface of the sheath
the chemicals tested did not persist. The deicing experiments showed that the chemical
tested was not viscous enough to sheet across the sheath surface. These results are
consistent with the results in the literature. In addition, to not performing the desired
anti/deicing functions, chemicals would require a distribution system so they were
deemed impractical.
Several anti-icing coating were tested in the icing wind tunnel and at the icing
experiment station. The coatings did not significantly delay the onset of ice, which stuck
to the stay specimens and most did not change the shape of ice that shed. The coating
that was outdoors for an extended duration of time became opaque and gummy,
therefore, it would alter the appearance of the stays. These results are consistent with
the results in the literature. Additionally, coating would be difficult to apply so they were
deemed impractical.
Introductory heating experiments were carried out at the icing experiment station. The
heating was effective at deicing and partially effective at anti-icing. The requirement to
heat each stay would require an expensive heating system. At that point, heating was
deemed impractical so no advanced experiments or thermal analyses were conducted.
Thus, no active or passive system was identified which had sufficient level of promise to
justify detailed estimates of installation, operation or maintenance costs.
When it was judged that the regional weather information and the RWIS did not provide
enough information to assess the microclimate and icing behavior, a local weather
station was installed on the bridge. The combination of the existing sensors and the

27
local weather station gives a good picture of the conditions on the bridge. Prior to
deployment in the field, experiments on the sheathing specimens at the field station and
in the laboratory coupled with the literature review lead to the conclusion that the
proposed sensors functioned as desired and they were recommended for installation.
To make the research immediately actionable by ODOT operations, a real-time icing
condition monitor was developed. The research team designed a real-time monitoring
system to track icing conditions on the bridge with a straightforward interface so
information on the icing of the bridge was readily available to the bridge operators. This
monitoring system is referred to as the “icing dashboard” or simply “the dashboard”
because the information necessary to support ODOT operations is presented on one
simple visual display. When conditions favorable to icing occur the dashboard alerted
the research team. If the conditions favorable to icing persisted, ODOT was notified
and, as required, requests for verification of ice accretion were made.
The basis of this monitoring system is the smart mix of the automated algorithm and the
visual observations, which helped aid in training the system for more optimal
performance. The system uses an intelligent decision making process based upon
initial criteria from past weather data analysis with parameter adjustments made after
visual observations. Dashboard has done well in detecting ice accumulation each time,
but the analysis done on the algorithm results and onsite observations from research
team members and ODOT have been used to refine the algorithm as well as the
interface.
The dashboard has proven to be a valuable resource for the bridge operators as well as
a valuable tool for reviewing weather events. The automated ice detection and
monitoring dashboard for the VGCS was developed, implemented, successfully tested,
and has been transferred to ODOT.
No suitable sensor to detect the continued presence of ice or the transition from ice to
water exists. Therefore, development and field testing of a suitable sensor were
undertaken. The resistance based sensor detects the presence of ice and can
differentiate between ice and liquid water. The sensor is designed to be mounted on
the sheath and can detect the layer of water which forms beneath the ice just prior to
shedding. The sensor has been tested in the laboratory and at the icing experiment
station.
The transition of the dashboard to District Two has concluded. A local standalone
computer with the dashboard on it has been provided to the District. The standalone
version maintains the basic functionality of the dashboard algorithms and alert system
and provides links to the icing weather instrumentation on the bridge. A person at the
computer can monitor the conditions on the bridge and determine the causes of alerts.
Section 1.4: Organization of this Report
Chapter one described background information regarding the VGCS, introduced the
problem statement of helping ODOT operations with icing problems on the VGCS, and
gave summaries of goals and objectives as well as results.

28
Chapter two discusses goals, objectives and benefits as well as introduces the expert
team.
Chapter three describes phase I research, which involved investigating the VGCS stay
sheaths, performing a literature review regarding icing events on other structures as well
as potential anti/deicing technologies, constructing a technology matrix to narrow down
the numerous technologies to a few viable ones was constructed, and providing the
history of sensor presence on the VGCS.
Chapter four looks into the basic weather that gives rise to ice storms, the VGCS’s
weather history, lessons learned from previous icing events, and accretion and shedding
algorithms.
Chapter five thoroughly discusses the development and testing of the icing dashboard as
well as its initial results.
Chapter six looks into each of new sensors implemented onto the bridge as well as
describes both the laboratory and field tests performed on the new sensors.
Chapter seven discusses the experimental studies performed on the sheath specimens
at the outdoor icing experiment station located at the University of Toledo’s Scott Park
Campus. This chapter gives detailed analysis and discussion regarding the potential
technologies tested as well as the new sensors that were eventually implemented.
Chapter eight describes the design and implementation of the local weather tower on the
VGCS.
Chapter nine discusses the development of the University of Toledo ice presence and
state sensor.
Chapter ten looks into the transition as well as the near-term and long-term maintenance
of the icing dashboard.
Chapter eleven provides a conclusion and recommendations for future work.

29
Chapter 2: Goals, Objectives, Research Approach and Benefits
Section 2.1: Overview of Chapter
This chapter describes the overall goals of the project, the objectives that were
achieved to reach those goals, the approach that was taken to reach the objectives and
the benefits that accrued to ODOT from this project achieving its goals.
Section 2.2: Goal
Under some winter conditions, ice forms on the cables stays of the VGCS. Ice
accumulations have been observed at a thickness of 3/4”. The ice accumulation
depends on the temperature, precipitation and duration of the storm. The accreted ice
conforms to the cylindrical shape of the stay sheath. Thus, as the stays warm, the ice
sheds in curved sheets. These curved sheets of ice then fall up to two hundred and fifty
feet to the roadway below and may be blown across several lanes of the bridge deck
depending on wind conditions and/or ice sheet aerodynamics. The falling ice sheets
require lane closures and could present a potential hazard to the traveling public.
The overall goal of this research was to assist ODOT in implementing an icing
management procedure for the VGCS. This procedure may be active, passive or
administrative. Active procedures involve anti/deicing measures that are typically
powered and activated only when needed. Passive procedures operate without power
and are continuously available, and include coatings or other technologies that are
permanently in place. Administrative procedures focus on obtaining information about
the condition of ice on the stays and pylon and managing the response to icing incidents
with or without taking anti/deicing measures.
Section 2.3: Objectives
The research followed a phased approach. The first phase focused on review of
available technologies, selection of potential technologies for the VGCS and costing of
the potential technologies. The second phase focused on the development and
implementation of a monitoring system and sensors.
The original objectives of this study included the conceptual design and rough costing of
three to five reasonable options, which included active or passive anti-icing or deicing
approaches applicable to the VGCS, for ODOT. Investigation of a wide range of
technologies was completed. No practical anti/deicing technology was identified.
Therefore, the objective shifted to the monitoring of icing events in order to provide
ODOT with the best information to manage their response to an icing event. The original
objectives as well as the modification of objectives will be described below.
The initial overall objectives of this study were to present three to five reasonable options
to ODOT for ice protection on the VGCS as mentioned above. The highest priority was
to identify cost effective methods to prevent the formation of ice on the stays. If suitable
methods for ice prevention were not identified, the secondary objective was to identify
methods to safely and efficiently remove ice from the stays without damaging the
structure or causing additional safety concerns and delays to the public.

30
The first phase objectives were as follows:
1) Identify available technologies and procedures that could be used to solve the
icing problem. Sixteen potential technologies were identified. Fourteen ice
protection technology categories are acknowledged for anti-icing, deicing, and
ice detection in the work by Ryerson (Ryerson 2009). There are many
technologies from Ryerson’s work that are potentially applicable to the VGCS
cables, which include: chemicals; icephobic coatings; structure design; expulsive
techniques; heat; high-volume water, air, and steam; infrared energy;
piezoelectric methods; pneumatic boots; vibration and appropriate ice detection
methods. Proprietary methods such as pulse electro-thermal de-icing (PETD), a
technique incorporating nano-fibers and a piezoelectric system proposed for
aircraft will also be considered (Petrenko 2009; Prybyla 2009, and Near 2009,
respectively).
2) Assess the state of the art through a literature review and consultation with
the icing experts. Given the unique features of the VGCS, the paucity of
literature directly on point, and the urgency of addressing the problem, an expert
team is a superior way to quickly gain familiarity with the state of the art as well
as define testing procedures and identify available facilities.
3) Examine the advantages, disadvantages, and potential applicability of each
identified technology on the VGCS.
4) Identify the most viable solutions. It is expected that the most practical
solutions will be novel adaptions or combinations of existing solutions.
5) For each viable solution, develop a detailed description of the implementation,
define required validation testing, (either in situ or offsite), perform a benefit/cost
analysis, develop a budget for implementation and define a time frame for
implementation. Because we expect that the solutions will be novel, it is
anticipated that some validation testing will be required.
6) Issue an interim report providing a summary of the findings from steps 1
through 4 and the recommendations and economic analysis from step 5 (Nims,
2011).
The research from Phase I resulted in the identification of several viable technologies,
which can be seen in Table 1. These technologies fell into three separate categories,
which were chemical distribution, chemicals, and internal heating. The technologies
deemed viable for chemical distribution included the use of drip tubes or cable climbers
with supply hoses or tanks. The chemicals that were further investigated were sodium
chloride, calcium chloride, and agricultural products. As for internal heating, forced air,
air with piccolo tube, steam heating elements and electrical heating elements were
considered.

31
Table 1: Viable Technologies
Category Specific Technology
Chemical
Distribution
Drip Tube
Cable climber with supply hose or tank
Chemicals
Sodium Chloride, Calcium Chloride, Agricultural-based deicing
products
Internal Heating
Potential options to be explored are: forced air, air with piccolo tube,
steam heating element and electrical heating elements
As part of Phase I, any proposed implementation was investigated in such a way that the
implementation would be as “green” as possible. If any of the potentially viable solutions
identified above in 5) required the use of a local power source, then cleaner alternative
forms of energy, such as solar power, was investigated and utilized if possible. If the
recommendation involved the application of chemicals, then the potential environmental
consequences were considered and avoided if possible.
At an icing team meeting during Phase I work (the meeting notes are in the interim report
(add cite)), it was identified that there was insufficient information concerning the ice
accumulation conditions, the ice shedding conditions, the microclimate of the bridge and
the effectiveness of the viable technologies to reasonably cost alternatives. Thus, the
team and ODOT decided that the uncertainties listed in Table 2 needed to be resolved.
Table 2: Information Required to Revolve Uncertainties
Required Information Uncertainties to be resolved
Presence of ice and/or
liquid water on stay
It is difficult to be certain when ice is forming on the stay, how
fast it is accumulating and if it is persisting.
Stay Sheath
Temperature
The temperature of the stays during an icing event is unknown.
It is considered as one of the reasons for shedding.
Sky Solar Radiation
Solar radiation may contribute to ice shed. Solar radiation
raises the stay temperature and the temperature between the
ice sheet and the sheath.
Local Weather
Conditions
The bridge has its own microclimate: precipitation amount and
type, droplet size, wind speed, wind direction, visibility needs to
be determined on the bridge.
Heat flow along stay
and across a stay
section
Characteristics of the distribution of the heat along the stay from
air flow and through the stay cross section from a local source,
and the VGCS specific constants for thermal analysis, need to
be determined.
Efficacy of anti/deicing
chemicals
The efficacy of the chemicals, the effect of the chemicals on the
brushed surface of sheaths, and a practical method for applying
the chemicals are unknown.
Visual record of
conditions
Observation of the unquantifiable aspects of icing on the VGCS.
Aerodynamic effects of
drip tube
A drip tube is a possible chemical distribution system. How the
drip tube effects the aerodynamics of the stays.

32
In response to a request by ODOT at a project progress meeting to make the research
immediately actionable by ODOT operations, a real-time icing condition monitor was
developed. This monitoring system is referred to as the “icing dashboard” or simply “the
dashboard” because the information necessary to support ODOT operations is
presented on one simple visual display. The need to resolve the uncertainties in Table 2
and build on the capabilities of the dashboard led to a modification of Phase II research,
which was initially focused on the implementation of viable technologies.
Final Phase II objectives were as follows:
1) Collect data to resolve uncertainties in Table 2. Some of the data may come
from existing sensors while some of the data required new sensors (discussed
later in this report), laboratory experiments and on-site observation. The
collected information should be sufficient to allow accurate costing, resolve
uncertainties to reduce the risk of deploying an icing strategy that does not work,
and be useful for improving and updating the icing dashboard. The uncertainties
to be resolved and the reason for resolving the uncertainty is listed in Table 2
above.
2) Make a recommendation on two to four viable active solutions. To make a
decision on the viability on an active system, it is necessary to have a reasonable
estimate of the cost and the practical implementation strategy.
3) Improve the icing dashboard. The dashboard tracks the icing events in a
format that is easy to understand, is useful for managing icing incidents and
archives data. Local condition data that is collected from the bridge will be used
to increase algorithm intelligence and error handling. The improvements focused
on the enhancement of the visual display, refinement of the accretion and
shedding algorithms and incorporation of data for a local weather station on the
bridge.
4) Development of an ice presence and state sensor. No suitable sensor exists.
Therefore, development and field testing were undertaken.
5) Transition the dashboard board and local weather station to ODOT District 2
so that the functionality of the dashboard and the information from the icing
sensors is available to the operators of the VGCS.
As with Phase I, any proposed implementation was to be as “green” as possible. If the
recommended solution involved the application of chemicals, then the potential
environmental consequences of the chemical waste stream were addressed and “green”
alternatives for conventional chemicals were investigated and utilized.
The experimentation of the viable technologies will be thoroughly discussed in chapter 7
of this report. Through experimentation, no practical active or passive anti/deicing
solution was ever identified. This ultimately led to a new overall objective, which was to
improve the monitoring of icing events in order to provide ODOT with the best

33
information to manage their response to an icing event.
Section 2.4: Expert Team Approach to the Research
Because of the unique nature of the problem, the need for a quick response and the
specialized nature of the icing knowledge required, the VGCS icing problem has been
attacked with an expert team. The primary requirement was a team of researchers who
are experts in ice and professionals familiar with the bridge. These are supplemented by
team members who are expert in instrumentation, “green” energy and “green” chemistry.
The team includes national expertise in icing from the U.S. Army Cold Regions Research
and Engineering Laboratory and the NASA Glenn Icing Branch, expertise on the VGCS
design and instrumentation, and experts in green technology. This team will address the
unique features of the VGCS stays and provide recommendations to the Ohio
Department of Transportation for the most practical and cost effective ice sensing, anti-
icing and deicing systems for the VGCS.
An expert team was the best way to rapidly assess the state of the art. This approach
allowed the research team to confirm that a practical solution for ice anti/deicing for the
VGCS does not currently exists. The icing experts have identified the information that
must be collected and understood to design an effective anti/deicing solution. The
research team consists of the following members:
Jeff Baker, P.E., Independent consultant who was formerly the construction manager for
VGCS, familiar with all aspects of VGCS construction and operation; experience with
VGCS icing incidents.
Nabil Grace, Ph.D., College of Engineering Dean, University Distinguished Professor,
Lawrence Technological University; Director, Center of Innovative Materials
Research; director of the LTU Comprehensive Environmental Test Chamber which
has large scale icing test capacity.
Michael Gramza, P.E., ODOT lead, District Construction Engineer for District 2, and
former construction project manager of the VGCS.
Cyndee Gruden, P.E., Ph.D., Associate Professor of Civil Engineering, University of
Toledo; environmental engineer with expertise in management of deicing waste
streams.
Art Helmicki, Ph.D., Professor, Department of Electrical and Computer Engineering,
University of Cincinnati; Director, Applied Systems Research Lab, a designer of the
data collection system for the VGCS; expertise in sensor and signal processing.
Victor Hunt, Ph.D., Research Associate Professor, Department of Electrical and
Computer Engineering, University of Cincinnati; expertise in bridge instrumentation,
a designer of the existing VGCS instrumentation system.
Kathleen Jones, U.S. Army Cold Regions Research and Engineering Laboratory,
Expertise; expertise in static and dynamic loads on structures due to atmospheric

34
icing; leader of freezing rain survey team; wrote ice load section for ASCE7
Standard, Minimum Design Loads for Buildings and Other Structures.
Richard Martinko, P.E., Director UT-University Transportation Center and Intermodal
Transportation Institute; former deputy director of ODOT District 2, former assistant
director of ODOT, and former ODOT project principal of all phases of the VCGS
project.
Cyril Masiulaniec, Ph.D., Late Associate Professor, University of Toledo, Department of
Mechanical, Industrial and Manufacturing Engineering; expertise in icing and
thermodynamics.
Douglas Nims, Ph.D., P.E., PI of this project, Associate Professor of Civil Engineering,
University of Toledo; instrumentation and structural study of the VGCS;
management of engineering consulting and academic teams.
Tsun-Ming “Terry” Ng, Ph.D., Professor, University of Toledo, Department of
Mechanical, Industrial and Manufacturing Engineering; expertise in icing and sensor.
Currently, working on a study of icing on wind turbine blades..
Andrew Reehorst, NASA Glenn Icing branch; expertise in icing sensors; experience with
ice accumulation and icing test facilities.
Charles Ryerson, Ph.D., U.S. Army Cold Regions Research and Engineering
Laboratory, Manager of CRREL’s Icing Program, Deep; deep and broad experience
with aircraft and structural icing. Familiar; familiar with icing test facilities. His 2009
study on off-shore facilities is similar to this VGCS study.
Thomas Stuart, Ph.D., Professor of Electrical Engineering University of Toledo; expert
in power, PI of an ODOT funded research study of a solar installation near to provide
power to the VGCS site.
Mario Vargas, Ph.D., NASA Glenn Icing Branch, lead. NASA Glenn has an icing wind
tunnel and the researchers are familiar with the capabilities of icing test facilities.
Ted Zoli, S.E., Vice President of HNTB, expertise in icing; an extensive history of
working with icing issues including testing structures on Mount Washington.
Currently, he is engaged on two other cable stayed bridges with icing issues.

35
Table 3: Team Members Roles and Expertise
Team member
Icing
Expert
Local
Knowledge
Green
Expert
Brief Description of Primary Activity/Expertise
Jeff Baker X
Former construction manager for VGCS, familiar with all aspects of VGCS construction and operation, experience with
icing incidents.
Nabil Grace X
Lawrence Technological University (LTU).  Director of a unique low velocity wind/ freezing/icing/rain/load testing
facility.
Mike Gramza X ODOT lead, former project manager of VGCS, able to provide input on ODOT operation needs.
Cyndee Gruden X University of Toledo.  Expertise in management of de‐icing chemicals
Kathleen Jones X CRREL, national icing expert, leader in icing risk, member and former chair of ASCE‐7 committee on icing
Art Helmicki X
University of Cincinnati. Instrumented VGCS, expertise in instrumentation and testing, support for implementation
and testing costing
Victor Hunt X
University of Cincinnati. Instrumented VGCS, expertise in instrumentation and testing, support for implementation
and testing costing
Rich Martinko X University of Toledo.  Understanding of ODOT operations, administrative support
Cy Masiulaniec X Late of the University of Toledo.  Icing expertise, lead in performing thermal analyses and experiments.
Doug Nims X
University of Toledo.  Lead in administrative support.  Instrumented VGCS, lead in developing background
information for alternative, support for thermal calculations, lead in report writing and costing.
Terry Ng X University of Toledo.  Icing expertise, lead in sensor development and experiments.
Andy Reehorst X NASA Glenn, icing sensor expert
Charles Ryerson X
CRREL, national icing expert, recently completed oil platform study which is parallel to the present VGCS study,
familiar with other test facilities nationally
Tom Stuart X University of Toledo.  A lead in the design of the VCGS solar array, expertise in power management
Mario Vargas X
NASA Glenn lead, aircraft icing expert, intimately familiar with test facilities at NASA Glenn and familiar with other
test facilities nationally,
Ted Zoli X X
HNTB.  National icing expert, consultant on VGCS design and construction, experience with icing problems on existing
bridges

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