Paul Martin, Mayor of York Shire, previewing the project at the CRC 2017 Showcase.
End-user statements
Denese Smythe, President, Shire of York, WA
The research from Geoscience Australia and the University of Adelaide in this Bushfire and Natural Hazards CRC earthquake mitigation study on six York building types is of immense benefit to the town. The results will not only be useful for York, they will enable the refinement and adaptation of the retrofit information for wider application to similar buildings elsewhere in the state and nation.
It is a great example of what is possible when organisations work together for shared goals; to preserve life in natural disasters and preserve Australia’s built heritage and the economies that depend on it.
Steve Gray, Department of Fire and Emergency Services, WA
The collaboration and engagement of the project team has been pivotal in the success of this project. There are many actionable items that can be applied to support DFES in fulfilling its role as the agency responsible for earthquake in WA.
Summary
By developing earthquake impact scenarios and an exposure database, this project has demonstrated the benefits in retrofitting a heritage listed town with buildings vulnerable to earthquake.
The project is now informing the actual implementation of the retrofit activity in York through a succeeding project that is expected to refine and disseminate a broader range of information to inform retrofit activity in other high risk communities across Western Australia and Australia.
Background
Earthquake hazard was not fully recognised in Australian building design until the mid-1990s. This oversight has resulted in a legacy of vulnerable buildings that can be readily damaged in moderate to severe Australian earthquakes.
In particular, older unreinforced masonry buildings built with the architectural styles, materials and construction details used in the United Kingdom are particularly vulnerable. Australian earthquakes have highlighted the vulnerability of these building types. These include earthquakes in Adelaide 1954, Meckering 1968, Newcastle 1989 and Kalgoorlie 2010, all of which mostly damaged pre-WWII masonry buildings.
The proportion of the community building stock in this age and construction category can be quite significant in many low growth Australian regional towns and contribute disproportionately to the earthquake risk of a community. The damage to these buildings can also greatly add to emergency management logistics after a major earthquake and can impede the recovery of the community physically, economically and socially.
York is Western Australia’s oldest inland town with many older masonry buildings that are particularly vulnerable to earthquakes. These legacy structures are greatly valued by the community and draw many visitors to the town, including those attending the large annual events hosted by York. They have great heritage value and many of the buildings are on the state and national heritage registers. The heritage precinct they create contributes significantly to York’s economy, supporting the local businesses by the tourist spending they attract to the town. The risk posed by these buildings is exacerbated in York by the local seismic hazard, which is high compared to most other parts of Australia.
Understandably, improving the resilience of these buildings is of interest to property owners, the community, the Shire of York, the Western Australian Department of Fire and Emergency Services (DFES) and the WA Department of Planning, Lands and Heritage (DPLH).
This case study reports on a Bushfire and Natural Hazards Collaborative Research Centre project that developed information on the most effective means to address York’s high risk buildings. It has also sought to develop a better understanding of the logistics that would be faced by emergency services and the local shire council in a rare, but credible, earthquake event.
Research
The study commenced in January 2018 and was undertaken over a two year period. It involved the University of Adelaide and Geoscience Australia as the CRC research partners, and WA DFES and DPLH, and the Shire of York as the end users. The project had the following key components:
Develop a building, business and demographic exposure database for York with the attributes collected tailored for modelling earthquake impact and for quantifying avoided consequences in economic terms.
Examine the benefits and costs of retrofitting old URM buildings to improve the resilience of them to earthquake. This is to range in scale from individual households and businesses up to the community as a whole.
Prepare earthquake impact scenarios suitable for emergency management planning by DFES and the Shire of York.
Significantly, the project has also examined how the scenario impacts and losses to the community would change over 30 years with different credible rates of implementation of retrofit measures.
The work required the development of the three fundamental risk elements:
earthquake hazard
community exposure
building vulnerability
It assessed the economic loss measures associated with human injury, contents losses, rental income, commercial property leasing, and business activity. It also included the application of the semi-intangible value placed on human life to society.
Benefits
Benefits have included reduced post event logistics for emergency management and the Shire, reducing financial losses to building owners, businesses, the Shire and the State, and reducing injuries and fatalities. It has also demonstrated that retrofitting reduces the long term financial cost of earthquake hazard, thereby making risk transfer through insurance uptake more affordable.
The project has developed a range of retrofit measures for a suite of six building types. These measures have been demonstrated to reduce the physical vulnerability of each building. The project has also translated this vulnerability change into broader metrics that form an evidence base to inform decisions to retrofit.
The success of this project is greatly attributable to the alignment of six key factors. York has a high earthquake hazard by Australian standards, it has a high proportion of vulnerable masonry structures, the same structures are very valuable from a broader heritage perspective, the town’s economy is highly dependent on the visitors attracted to York to enjoy the older building stock, the town hosts many large annual events centred in its heritage precinct and the local stakeholders have been highly engaged and motivated to understand and address this risk.