There are over 30,000 small road bridges and many thousands more pedestrian bridges in Australia, many of which are coming to the end of their structural lives. The cost of replacing these bridges is colossal, and could impose a crushing burden on councils, which are responsible for the vast majority of these, mostly timber, bridges.
To complicate matters, the legal responsibilities for councils and road authorities have changed enormously with the decision by the High Court to abolish the concept of nonfeasance. While a number of Australian states have legislated to protect councils and other road authorities, the legal position has been dramatically altered and continues to evolve.
Bridges built decades ago now have to withstand far greater and heavier traffic, which is imposing greater risks and forcing councils and road authorities to search for cost effective solutions and to improve their management of their bridge assets.
The Fifth Australian Small Bridges Conference, a recent two-day event in Surfers Paradise, focused on the problem of small to medium bridges (which account for around 85% of the national structures stock). A knowledgeable audience of state and federal bridge, highway and rail engineers, managers, contractors and suppliers heard about significant new developments in policy and methods for maintaining their assets. Fiscal and technical challenges facing all levels of government were discussed and explored with practical solutions debated. One of the most significant challenges facing the Australian market is extending/managing the condition of its assets and this issue was high on the agenda at the conference and stimulated off-line discussion.
BridgeZone, a well established and leading provider of structural engineering consultancy services involving rope access, underwater and confined access inspection services, was invited to address the audience on the techniques it employs. Paul Marshall and Kimble West gave a well-received presentation and, through networking and active participation at the conference, it became apparent that the Australian market as a whole is carrying out very little difficult access inspection and virtually no systematic underwater inspection of bridges. In truth, most inspections seemed to be reactive. However, as risks increase – when, for example, the age and, more importantly, condition of an asset is acknowledged as a serious problem or when infrastructure new- build is slacking – asset management as a concept is‘on-the-rise’.
In Australia there are‘abseilers’and a number of commercial diving companies that provide a ‘service’, but none with an engineering inspection background. Feedback from the Australian visit revealed that many of the country’s contractors, consultants and client organisations believe BridgeZone has the expertise they badly need.
Sonar sounds interesting
Particular interest was shown in BridgeZone’s application of sonar technology for sub-surface scanning of underwater structures in conditions where normal visual inspections are not possible. Underwater environments are dynamic and complex and the sub-surface visual assessment of structures has long been a challenge for inspection engineers the world over. Introducing a sonar scanning capability was a natural progression for BridgeZone; the company has invested heavily in the technology and is already seeing a return through successful trials and contracts on a number of inspection projects in the UK, Ireland and Africa.
Surface operated, thus negating the need for diving, BridgeZone’s sonar scanning equipment is both light and versatile. The resulting high quality images provide clear definition to reveal critical structural defects such as scour pockets in exceptional detail even in very low visibility water. The images can then be interrogated to calculate approximate depths and areas of defects and scours, thus helping to quantify any necessary detailed dive examination and associated remedial works.
Encouraged by the overall experience at the conference, Bridgezone is now actively progressing collaboration with like-minded organisations in the Australian market. Based on its experience as a specialist provider of difficult access inspection of infrastructure assets in highways and rail in the UK, Europe and Africa, it aims to promote its effective and efficient methods for gathering crucial asset condition information using specialist access techniques.
As managing director Paul Marshall puts it: “Australia is most certainly a land of great opportunity. Following the intense schedule during our visit our overall perception was that this market is calling out for asset management support and our expertise was of real interest to many of our potential clients in both public and private sector organisations.”