Advanced research for safe infrastructure
Professor Brian Uy and Scientia Professor Mark Bradford
When it comes to rehabilitation, structural engineers at UNSW are less concerned with mending broken bones and torn muscles, and more concerned with strengthening our ageing buildings and infrastructure – to keep us safe and to make the construction industry more sustainable.
In most modern construction projects there is a need to connect steel and concrete elements. In fact, composite steel-concrete beams have become the most widely used method of construction for steel framed bridges and buildings. In NSW, the Star City Casino, Sydney Olympic Stadium and the Hawkesbury River Bridge all use composite beams.
Unfortunately, many existing composite structures may not satisfy current load requirements and require retrofitting or “rehabilitation” to extend their design life, saysProfessor Brian Uy, Director of the UNSW Centre for Infrastructure Engineering and Safety (CIES).
According to a 2009 infrastructure report card produced by the American Society of Civil Engineers, approximately one in four rural bridges in the US, and one in three urban bridges, were deficient. In Australia, where the country’s last infrastructure report card was produced in 2010, and gave very poor ratings to both roads and rail, it’s likely that conditions are similar.
Replacing this infrastructure is costly and demolition means significant waste ending up in landfill. (According to the Green Building Council of Australia, roughly 40 percent of landfill waste can be attributed to construction activities).
Uy says the workaround is for engineers and architects to consider the whole lifecycle of a building or infrastructure project, and to design structures that can be more easily deconstructed and re-used, or rehabilitated.
“Steps that structural designers can take to maximize the potential for re-using steel infrastructure include using bolted connections in preference to welded joints and ensuring easy access to connections,” he says.
Uy and his team have developed an innovative method for connecting steel and concrete elements using blind bolts. He presented the findings in December 2013 at the International Conference on Structural Health Monitoring of Intelligent Infrastructure in Hong Kong.
“The paper has illustrated that the service and strength behaviour of these blind bolt-connection systems is similar or significantly improved to that of welded headed shear studs,” he says.
“These systems – which will see increased utilization in next-generation infrastructure – can facilitate improved structural health monitoring, as both the service and strength behaviour can be characterised.”
The CIES – which has an extensive portfolio of research topics – is also working on keeping structures safe from unexpected shocks, such as fires and explosions, earthquakes, and other extreme weather events.
Building and infrastructure design codes in Australia – and around the world – attempt to provide protection for structures against the effects of certain unforeseen events and natural disasters, but the level of protection is not known, says Uy.
Along with Scientia Professor Mark Bradford, he has been investigating the impact and blast load behaviour of hollow and concrete filled steel columns; and how the properties of these materials react to extraordinary strain rates.
In 2013, this research got a considerable boost when the Australian Research Council awarded CIES a Linkage Equipment and Facilities Grant to build the National Facility for Physical Blast Simulation. This facility means controlled blasts that once needed to be conducted in remote canyons, can now be safely conducted in laboratories with more sophisticated instrumentation to observe and measure the results.
Installation of the facility, which will support the research activities of 10 Australian universities, is currently underway at the School of Civil and Environmental Engineering’s Heavy Structures Lab at Randwick.
More information:
Professor Brian Uy
b.uy@unsw.edu.au
- See more at: https://www.engineering.unsw.edu.au/civil-engineering/advanced-research-for-safe-infrastructure#sthash.7xnTip1a.dpuf