ENGINEERS from specialist firm Hevilifts used 10 Campbell Scientific CR10X dataloggers tomonitor the jacking of the M2 Medway Bridge during repair work.
The system alerted Hevilifts' engineers by mobile phone if any problems arose, freeing them up to work on other jobs.
Hevilifts' Jim Blair said: 'Using individuals to continuously monitor all the elements of the structure's performance would have been extremely time consuming and expensive. The CR10Xs did the job automatically and faultlessly in the very exposed conditions and they also enabled us to monitor the performance of our lifts.'
Main contractor Edmund Nuttall was strengthening the bridge's precast beams at their support points, which involved jacking the deck up at each of the 20 piers. Each carriageway of the bridge is a separate structure with four longitudinal beams supported on separate bearings. This meant that the jacking system had to lift eight beams simultaneously so that the traffic flows above were not affected.
Hevilifts monitored the jacks to check that no settlement was more than 2 mm.
At each pier, a group of 10 jacks were linked to a single pump. Each pair of jacks had a pressure transducer in a hydraulic circuit fitted and there were six linear transducers to monitor the deck movement.
A datalogger at each pier collected information from the pressure and linear transducers, feeding it on to a host PC in the site office. The PC monitored each logger at three-hour intervals, with any anomaly triggering an alarm. At the same, a message was sent to a Hevilifts' engineer on their mobile phone so that they could connect remotely and take the necessaryaction or advise people on site.