Stopping bridges from cracking up

Research from the Queensland University of Technology has demonstrated that hidden cracks and fractures in the structure of bridges can be detected by monitoring vibrations over time.

QUT engineering researcher Henry Shih said variations in bridge vibrations could be a telling sign of its structural ‘health’.

‘It's not always possible to see damage to a bridge, but using vibrations it is possible to "see" what can't be seen,’ he said.

‘Changes in the physical properties of a structure, such as cracks and fractures in a bridge, will cause changes in its vibration. By monitoring these vibrations it is possible to detect any changes which may indicate bridge damage.’

QUT has undertaken research in bridge vibration for more than 10 years and this has involved monitoring vibrations in some of Brisbane's bridges. As a part of this on-going research programme, Shih will develop models to assess the damage in certain types of bridges.

‘Bridges form an important part of civil infrastructure and are normally designed to have long life spans. But changes in load characteristics, deterioration with age, environmental influences and random actions may cause damage to bridges,’ Shih said.