Anzac Bridge SHM – Sydney | Australia

Context

The ANZAC Bridge is an eight-lane cable-stayed bridge located on the west side of Sydney. The bridge is 32.2m wide and the main span is 345m long. The reinforced concrete pylons are approximately 69m high and support the deck by two planes of stay cables. The bridge can carry a maximum of 180,000 cars per day and is a critical part of the infrastructure of the global Sydney road network. However, the stay cables were considered slightly under designed considering the current and potential fatigue loads.

Solution

Sixense were appointed to install a structural health monitoring system (SHM) for Transport for New South Wales to the bridge to check the behaviour of the stay cables on the long run for detecting at the early stage any potentiel degradation.

The monitoring system consists of two main systems:

• EverSense® This monitoring system – commissioned in 2011 – records the physical parameters related to the stay cables, such as dynamic vibrations caused by wind or traffic.
• EverSense® Acoustics – commissioned on 2013 – monitors and records abnormal sound emissions resulting from probable wire breaks of pre-stressed structures. It provides information that can be analysed to determine likely sources and locations of the origin of the breaks. This system also monitors the tensions in stay cables.

Data is continuously recorded and processed in real-time to trigger alarm in case of exceedance. In addtion, quarterly reports are provided to the owner highlighting the evolution of the structure.