Remote Health Monitoring for Asset Management

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Figure 5.9. Satellite photograph of the location of the test site where the prototype pile will be installed. ........................................................................................................................................ 34 Figure 5.10. Schematic diagram of wireless data connection for remote monitoring of test pile. ....................................................................................................................................................... 35 Figure 5.11. Schematic diagram of prototype test pile. ............................................................... 36 Figure 5.12. Photograph of Stealth computer used for data acquisition from temperature sensors. ....................................................................................................................................................... 37 Figure 5.13. Photograph of the test pile installation at Hinkson Creek. ...................................... 38 Figure 5.14. Temperature profile along the test pile for high, low and initial air temperatures. .. 39 Figure 5.15. Schematic diagram of test pile showing locations where heat was applied (top) and resulting temperature measurements along sensor array. ............................................................. 40 Figure 5.16. Standard deviation of temperature outputs for three time intervals: 24 hr. period, average of 24 hr. periods for 7 days, and standard deviation over a 7 day period. ....................... 41 Figure 5.17. Standard deviation of temperature data from sensors along the height of the pile. Plot shows the average 24 hr. standard deviation for 7 days, and error bars showing the dispersion (standard deviation) of the results. .............................................................................. 42 Figure 5.18. Plot showing temperature variations along the pile as a function of time over 15 days. .............................................................................................................................................. 43 Figure 5.19. 3-D plots of plots of pile temperature profiles showing local heating at air/soil interface. ........................................................................................................................................ 44 Figure 5.20. Screen capture from the test pile web site showing A) homepage and B) historical data. ............................................................................................................................................... 46 iii
Executive Summary This project explored the development of real-time bridge monitoring technology to be used for the effective asset management. The management of the almost 600,000 bridges in the National Bridge Inventory (NBI) provides a significant challenge to bridge owners and engineers. It is estimated that there are more than 90,000 bridges in the NBI that have unknown foundations, complicating decision-making in regards to maintaining the safety and operation of these critical assets. Additionally, there are more than 26,000 bridges in the U.S. identified as scour critical, such that erosion at the foundation of these bridges has the potential to lead to structural instability and bridge failure. As a result, there is a critical need to develop technologies to assess and monitor the condition of these bridges over time, to improve the information available to decision-makers such that effective asset management strategies can be employed. This project investigated the development of an instrumented pile that could provide real-time data on bridge scour, allowing for the remote monitoring of bridge conditions by key managers and engineers. The developed technology has the potential to identify hazardous conditions at a bridge site, such that managers and owners can be notified automatically and appropriate actions can be undertaken. The instrumented pile monitors the temperature along the length of a pile embedded in the soil in a river bed. Monitoring the temperature profile along the length of the pile shows the thermal variations that exist in the water and in the soil, as a means of estimating where the soil / water interface exists. If a scour hole develops in the area of the pile, the depth of the soil / water interface is consequently changed, and this change is detected by thermal variations detected along the length of the pile. This technology provides a practical means of managing a bridge asset by reporting on potentially dangerous scour conditions such that mitigation strategies can be employed. An innovative new sensor array technology was developed that improves the reliability of field measurements by eliminating the majority of the wires required to make the measurements. A low-cost digital temperature sensor was selected for this application. New manufacturing processes were developed to provide a sensor array that can be integrated into a pile to be embedded at the bridge site. These processes were developed to provide a rugged, fieldable sensor technology that could be applied under a variety of implementation schemes. Laboratory studies of prototype sensor arrays were conducted to determine the adequacy of the sensor for this application. Software was developed and tested that supports long-term monitoring of sensor outputs. A prototype pile was designed and constructed that utilized an array of 64 sensors along the length of the 20 ft. pile. The test pile was installed in Hinkson Creek, Columbia, MO. Software to support monitoring the test pile over the web was developed and implemented. Initial test results from the pile installation are included in the report. The test pile was successful in demonstrating the feasibility and operation of the newly developed sensor array technology. 1
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Page 3 and 4: FINAL REPORT RI07-002 Remote Health
Page 5: List of Figures Figure 2.1. Photogr
Page 9 and 10: States as a means of technology tra
Page 11 and 12: where the soil / water interface ex
Page 13 and 14: from a sensor, the micro-controller
Page 15 and 16: solder connections, simplify manufa
Page 17 and 18: Figure 3.5. Photonegative used for
Page 19 and 20: temperature changes that could be m
Page 21 and 22: Figure 3.11. Diagram of the 48 in.
Page 23 and 24: Two ceramic heatplates were used to
Page 25 and 26: stores the data at a specified rate
Page 27 and 28: TEMPERATURE(°C) 60 50 40 30 20 10
Page 29 and 30: 45 109 TEMPERATURE (ºC) 40 35 30 2
Page 31 and 32: 50 TEMPERATURE ( F) 50 55 60 65 70
Page 33 and 34: 5 Field Implementation of Technolog
Page 35 and 36: the array after the epoxy has been
Page 37 and 38: 33 91 31 TEMPERATURE (ºC) 29 27 25
Page 39 and 40: Figure 5.8. 3-D graph showing senso
Page 41 and 42: interval. A time interval of 15 min
Page 43 and 44: 5.13, a portion of the pile is inst
Page 45 and 46: several days. Temperatures increase
Page 47 and 48: Where is the sample mean and n is
Page 49 and 50: The data can also be observed as a
Page 51 and 52: to select a different time period f
Page 53 and 54: 6 Conclusions This research has exp
Page 55 and 56: REFERENCES 1. Richardson, E.P.-O.,

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