Earthquake-Proof Skyscrapers?

Earthquake engineering is getting a lot more exposure recently, with websites like Gizmodo reporting on research into testing light wooden frames for large buildings – traditionally a material only used in small residential buildings in the Western world. It’s nothing new, of course, and with the world’s tallest timber building already residing in Melbourne we have a great opportunity to monitor real-world building response. It will be interesting to see how structures like these perform relative to their concrete counterparts when an earthquake eventually gives them a shake, and with strong motion accelerographs readily available we hope that building authorities start to look at instrumenting more buildings to monitor actual structural response and compare the data to the theoretical models used in the design process.

Structural Health Monitoring

Here is an interesting article from Queensland University of Technology about a structural health monitoring system embedded in one of its buildings. Buildings are typically noisy locations for seismic monitoring, but the recent earthquakes off Fraser Island were sufficiently large to be detected by this building monitoring system, although it should be noted that the earthquakes were also visible on dam monitoring seismographs operating as far away as Tasmania.

The Australian water industry, mainly driven by ANCOLD, is the most proactive in monitoring structures for earthquake response in Australia. AEES encourages other asset owners, including building owners and operators, to monitor their structures to better understand building performance during an inevitable earthquake.

A strong motion accelerograph mounted in an Australia dam

A strong motion accelerograph installed in an Australian dam

Shaking Up Australians’ Beliefs

Christchurch-masonryA 6.2 magnitude earthquake – the size of the destructive 2011 Christchurch earthquake – happens in Australia every 10 years, according to engineers and seismologists at the recent Australian Earthquake Engineering Society conference.

“Australians are unaware of the frequency with which earthquakes of this magnitude occur in our country. It is a rare but foreseeable scenario,“ said Dr Paul Somerville, President of the Australian Earthquake Engineering Society.

“The impact of such an earthquake on any one of our cities would be devastating given that few modern buildings in Australia are designed to adequately resist the ground motion arising from such large seismic events. The risk is even greater to older buildings.

“Whilst earthquakes occur infrequently, the risk as assessed by the insurance industry is high, given the high density and vulnerability of city buildings.

“In Christchurch many people were killed by falling masonry, especially parapet walls, and that is also a very likely scenario in Australian cities. Many were also killed in the collapses of poorly designed concrete frame buildings.

“Governments and city councils should take measures to mitigate these well-known risks. They should also foster an environment in which new construction follows design procedures and construction practices that provide the robustness and resilience that buildings require to withstand earthquakes.

“City councils will be at the forefront of response and recovery following the next earthquake, as was the Newcastle City Council after the destructive earthquake there 25 years ago this month.

“Council engineers have an important role to play. They should identify and foster the repair of hazardous buildings, especially schools and hospitals; establish good communication links with Emergency Management Australia; compile a list of trained Urban Search and Rescue engineers in their area; and make plans for earthquake response and recovery.

“The possibility of a large earthquake occurring in an Australian city is very real. The minimal costs of improving earthquake safety in our buildings are dwarfed by the massive economic losses and loss of life that could occur in Australian cities should we ignore the risk,” said Dr Somerville.