The ODOT Bridge Inspection Manual ( ODOT, 1973)was used to rate the condition of the AWB (Burgess & Nipple, Inc., 2008). Condition rating for protective coating system of suspension components was 6 indicating greater than 5% and less than 10% of the total protective coating system has failed. The main cables individual rating was 2, which is classified as fair condition and the suspension part of the bridge was classified as satisfactory with rating of 6. The following are the locations suggested to be inspected thoroughly based on deficiency in main cables with water retention being prime cause:
• Downstream Cable at panels: 5, 7-11, 14-18, 23, 25, 27, 30, 32-35, 39, 41-46, 48, 49, 51, 55-58, 60, 63
• Upstream Cable at panels: 5-8, 10, 20, 37, 41, 43, 44-47, 50, 55-60, 62
The most recent inspection was the one carried out in November, 2012. Modjeski and Masters (2013) performed the inspection in accordance to NCHRP-534 (Mayrbaurl & Camo, 2004). The inspection was carried on total of four panels from where a total of 13 wire samples were cut and taken for laboratory testing. While conducting tensile test on these sample wires, the ultimate failure strain was not recorded. Therefore, the ‘Ductile Wire Method’ of cable strength prediction could not be applied and the ‘Brittle Wire Method’ was used to estimate the factor of safety of the main cables. However, as there is no evidence of wire break, the wires are possibly more ductile than assumed and ‘Brittle Wire Method’ could have underestimated the safety factor. The samples from only 4 panels were statistically unreliable based on NCHRP-534.
The Cable Strength Evaluation Report (Modjeski & Masters, Inc., 2013) estimated the controlling factor of safety to be 2.41 which will rea...
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...ial secondary/ noise acoustic emission sources and lastly, the fifth experiment simulates a wire break which is the primary source under concern.
Chapter 4 – Review of Data from AWB: The knowledge gained from literature review and laboratory experiments has been utilized in analysis of recorded data from AWB. Description on the installed AE system is presented. A detail analysis of the data from June 2013 for both north and south cable is presented followed by a summary of analysis results from previous four months. It also includes data analysis from the invasive inspection period of 2012.
Chapter 5 – Conclusions: This chapter summarizes the results from the study and provides recommendation for future works. Suggestions for improvement of the monitoring system are provided. In addition, insights are provided for developing improved laboratory testing strategies.
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