Wireless Testing of Jiangyin Suspension Bridge
The bespoke development of pioneering technologies in synchronised wireless data logging enabled modal testing of the 1,385m span Jiangyin Suspension Bridge which crosses the Yangtze River in Jiangsu province, China. This testing was to evaluated the health condition of the structure for JSTI Group, an engineering consultancy service based in China. The Vibration Engineering Section from University of Exeter developed and honed pioneering technologies to carry out modal testing on a super scale structure, developing a bespoke synchronised wireless data logging system which can be widely distributed across huge structures, whilst maintaining sub-microsecond synchronisation without logistically challenging cables or GPS antennae.
Four loggers, along with 12 force balance accelerometers and short signal cables, were synchronised to a fraction of a microsecond before a measurement, then distributed over the bridge deck and towers in a sequence of measurements to record ambient vibration signals. Over three days, 14 separate measurements were taken and, for each measurement, the master logger was left recording vertical and lateral vibrations continuously at two hanger locations on the east walkway. Meanwhile, other (slave) loggers were ‘roved’ to record for at least an hour synchronously at other locations on the east and west sides and inside the south tower.
The second major technology evaluated was the operational modal analysis planning and evaluation procedure developed by Professor Siu-Kui Au’s group as part of the BAYOMALAW collaboration with the University of Liverpool. Modal analysis, measuring how structures respond to vibrational excitation, can offer insight into the design and maintenance of resilient civil structures such as bridges and skyscrapers. However, the enormity of these structures means traditional, wired data loggers are simply not fit for this purpose.
Application to VSimulators
Results and information from this case study are beneficial in expanding knowledge on how to perform health monitoring of super structures. VSimulators, as a testing platform, enables the the vibration signals to be fed into the facility, to accurately replicate movement within the structure, combined with a virtual reality environment and consequently to support decision making. The replicated environment could be explored by users, contractors, and owners to provide a realistic understanding as to how the super structure feels and functions.
For full information on our work with JSTI Group in China at Jiangyin Suspension Bridge, please visit the vibration engineering webpage here.
Please contact us if you wish to discuss a similar idea or problem.