A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Acoustic monitoring of post-tensioned bridges
In recent years much experience was gained with continuous acoustic monitoring of monostrands and stay cables. There is little experience, however, with monitoring of post-tensioned bridges with bonded tendons because of the structural complexity and the lower energy released when a wire breaks. To evaluate the diagnostic performance the acoustic monitoring system SoundPrint has been installed in April 2004 on a road bridge. This bridge, the Ponte Moesa, was built in 1952 and is one of the first prestressed concrete bridges in Switzerland. It is longitudinally prestressed and has two spans of 30 m. Insufficient grouting and de-icing salts among other causes have led to deterioration and wire breaks. Blind tests have been conducted generating artificial wire breaks by means of electrolytic corrosion-cells. Additionally, several spontaneous wire breaks occurred. The signal of a wire break can be distinguished from other acoustic events such as noises from expansion joints, bearings, traffic and other ambient sources. To evaluate the practicability of acoustic monitoring the results were compared with those of a conventional invasive examination and those of potential mapping. The diagnostic performance of the continuous acoustic monitoring system SoundPrint was evaluated with blind testing. Even in a noisy environment the system was able to identify and locate wire breaks in fully grouted and partially grouted tendons. Invasive inspections confirmed spontaneous wire breaks that were also detected during the monitoring. The results of half-cell potential measurements matched with the monitoring. Almost all located spontaneous wire breaks concentrated in one area with higher likelihood of corrosion.
Acoustic monitoring of post-tensioned bridges
In recent years much experience was gained with continuous acoustic monitoring of monostrands and stay cables. There is little experience, however, with monitoring of post-tensioned bridges with bonded tendons because of the structural complexity and the lower energy released when a wire breaks. To evaluate the diagnostic performance the acoustic monitoring system SoundPrint has been installed in April 2004 on a road bridge. This bridge, the Ponte Moesa, was built in 1952 and is one of the first prestressed concrete bridges in Switzerland. It is longitudinally prestressed and has two spans of 30 m. Insufficient grouting and de-icing salts among other causes have led to deterioration and wire breaks. Blind tests have been conducted generating artificial wire breaks by means of electrolytic corrosion-cells. Additionally, several spontaneous wire breaks occurred. The signal of a wire break can be distinguished from other acoustic events such as noises from expansion joints, bearings, traffic and other ambient sources. To evaluate the practicability of acoustic monitoring the results were compared with those of a conventional invasive examination and those of potential mapping. The diagnostic performance of the continuous acoustic monitoring system SoundPrint was evaluated with blind testing. Even in a noisy environment the system was able to identify and locate wire breaks in fully grouted and partially grouted tendons. Invasive inspections confirmed spontaneous wire breaks that were also detected during the monitoring. The results of half-cell potential measurements matched with the monitoring. Almost all located spontaneous wire breaks concentrated in one area with higher likelihood of corrosion.
Acoustic monitoring of post-tensioned bridges
Akustische Überwachung von nachgespannten Brücken
Fricker, S. (author) / Vogel, T. (author)
2006
9 Seiten, 10 Bilder, 2 Tabellen, 9 Quellen
Conference paper
Storage medium
English
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