Structural Monitoring: Auckland

Challenge

Auckland’s Ferry Terminal is a historic landmark on the waterfront. Over the 100 years since being built, the sea wall supporting the building was gradually eroded by constant sea movement and wash from ferries docking and leaving the port. Divers identified a three metre breach in the wall caused by the erosion and Auckland Transport brought onboard the engineering company CKL to carry out structural monitoring during the stabilisation and remedial works.

In addition to a Sokkia Total Station, which was used as a failsafe and gross error checking mechanism, CKL selected Senceive’s wireless Remote Condition Monitoring solution, which was introduced to them by the New Zealand Senceive Distributor; Position Partners. The wireless system would show, in near real-time, how the building would behave so that early warning alarms could be initiated quickly in order to safeguard workers.

Solution

 

Position Partners proposed installing six high precision triaxial tilt sensors along the sea wall, under the wharf. The mesh network formed by these wireless sensors relay data to a secure cloud server, via a solar powered cellular gateway. Registered users of Senceive’s WebMonitor visualisation software could then view the data.

Alert levels, which were defined by Auckland Transport, could all be remotely changed so that any movement could be prioritised and appropriately escalated. The system provided the clients with the reassurance needed with up to the minute data and, if required, the ability to change reporting rates and text alert trigger levels remotely.

Outcome

CLK and Auckland Transport were very satisfied with the results. The robust IP66/68 rated enclosure with protective antenna cap made it ideal for the harsh saline environment which the nodes were constantly exposed to, with the nodes appearing as new 18 months after installation. The long battery life of up to 12-15 years also allowed for the monitoring duration to be extended and eliminated the need for any kind of intervention or maintenance, which reduced the risk to site workers as well as saving CKL considerable amounts of labour and costs compared with manual monitoring of the structure.

The sea wall was successfully repaired and the Ferry Terminal continues to serve the Auckland community. Position Partners continue to offer local support in New Zealand, as Senceive’s Oceania Distributor, and offer full customer support and technical assistance.