@article {bnh-8215, title = {Cost-effective mitigation strategy development for building related earthquake risk {\textendash} Melbourne case study}, number = {707}, year = {2021}, month = {09/2021}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

Earthquake hazard was not fully recognised in Australian building design until the mid-1990{\textquoteright}s. 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 (URM) 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 this building type. These events include the Adelaide Earthquake of 1954, the Meckering Earthquake of 1968, the Newcastle Earthquake of 1989 and the Kalgoorlie Earthquake of 2010, all of which damaged pre WWII masonry buildings in particular.\  Buildings of this style are present in the older centres of our major cities, and Melbourne has a very significant number of these. As shown in this research, in number nearly half of the buildings in the Melbourne central business district are of this type of construction. The damage to these buildings can greatly add to human casualties as a result of falling masonry elements. Further, the severity of damage and losses can impede the recovery of cities like Melbourne physically, economically and socially. Finally, many of these buildings have heritage value to communities that residents may want preserved.

This document reports on the final deliverable for Project A9 Cost-effective mitigation strategy development for building related earthquake risk of the Bushfire and Natural Hazards Collaborative Research Centre (CRC). It builds on the masonry component research of the University of Adelaide in this project and is a milestone for Geoscience Australia. The work follows the utilisation project entitled {\textquotedblleft}Earthquake Mitigation of WA Regional Towns: York Case Study{\textquotedblright}, that was jointly delivered by GA and the University of Adelaide. The utilisation project developed original condition and mitigated vulnerability models for six URM building types. In this project, these outcomes have been applied to the much larger Melbourne CBD exposure.

The project had the following key components:

The work required the development of the three fundamental risk elements of earthquake hazard, community exposure and building vulnerability. It also entailed the assessment of the economic loss measures associated with human injury, contents losses, rental income, commercial property leasing, and business activity. Additionally, it included the application of the semi-intangible value placed on human life to society. Each of these are described below.

Earthquake hazard

This study has drawn upon the latest understanding of the Melbourne region earthquake hazard by utilising the recently released National Seismic Hazard Assessment (NSHA 2018) (Allen et al, 2018a). The bedrock hazard from this assessment shows Melbourne to have a {\textquotedblleft}low{\textquotedblright} earthquake hazard by global standards but significant by Australian standards. The hazard is further amplified by the presence of the sediments deposited by the Yarra River.\  These soil effects increase the hazard, particularly those in the study region south of the Yarra River. The effects of soil amplification can double the severity of shaking in some areas.

Community exposure

The definition of the building assets in the study region utilised several sources. The available state government building data integrated into the National Exposure Information System (NEXIS) was accessed and supplemented by an engineering survey database developed and maintained by GA for the Australian Reinsurance Pool Corporation. This was further refined by a desktop review of all masonry buildings utilising available street level imagery. In total there were 1,543 buildings in the study region, and 687 of these were identified as URM.

The assessment of human activity was achieved by utilising research undertaken outside of this project. This research utilised a population model developed by downscaling a destination zone based telecommunication model with pedestrian counts, the Melbourne traffic control systems movement counts, and building floor area information. Using this work it was possible to define the local human exposure at the time of the scenario event, particularly those in damaged buildings and those potentially exposed to falling masonry during a rapid onset earthquake event.

Building vulnerability

The building vulnerability assessment work for the URM building stock was a direct utilisation of the six vulnerability types identified in the earlier York WA mitigation study. This included the vulnerability in present condition, and that with mitigation measures applied to the vulnerable elements. To complete the context, the vulnerability of other building types was attributed using a suite of models developed through an adaptation of US HAZUS models, reference to \ heuristically developed models from a GA facilitated UN workshop (Maqsood et al, 2014), and through heuristic adjustments by the project team. This vulnerability of non-URM buildings remained a constant in the study as mitigation of these buildings was not considered.

Economics of cost assessment

The economic assessment considered a broad range of measures. These ranged from the direct costs to property owner, building occupiers, and businesses through to health care costs and the partially intangible value placed on the loss of a human life. The aim was to provide scalable information on benefits versus cost to a range of decision makers and investors. Importantly, the measures where not comprehensive and so represent a lower bound to the actual avoided impacts mitigation achieves. For example, the cost of emergency response, clean-up and community recovery support were not considered. Neither was a macro-economic perspective developed to capture non-impacted businesses that would benefit from a stimulus in business activity such as in the construction industry, the supply of home appliances, soft furnishings and drapery. Significantly, the value of avoided heritage building loss was considered through the utilisation of metrics developed by a UWA led CRC project.

Scenario impacts and risks

The study considered a single rare earthquake scenario having an annual likelihood of 1/5,000 of causing the targeted bedrock shaking severity beneath the Melbourne CBD, or greater. This likelihoods corresponds with a 1\%, chance of this shaking severity being exceeded in the next 50 years. For the event the injuries and other losses within the scope of this study were assessed using the human exposure corresponding with 11:00am of Monday through to Thursday. The losses ranged from $737m for building damage only, through to $1.66b for the other monetary costs considered.\  The value of human life lost increased this to $3.97b. Where 25\% of the masonry building stock was retrofitted, over 30 years, these losses reduced by approximately 16\%.

The reduction in injuries if this event occurred in 30 years time was also evaluated. Serious injuries reduced by 16 and deaths by 98 persons. Urban Search and Rescue logistics would also reduce correspondingly.

In a similar manner, the long term financial risk of the Melbourne CBD study region was evaluated for building damage. It was presented as the average annualised loss for the URM building stock and for the entire study region buildings. It was also forecast 30 years into the future and the financial risk reduced by 38\% for the URM building stock and by 10\% across the entire study region buildings.

Discussion and outcomes

Earthquakes occur frequently in Australia with over 100 events greater than magnitude 3.0 (ML) recorded within the Australian continent every year by Geoscience Australia. The smaller and more frequent events are typically non-damaging, whereas the less frequent larger events can be very damaging when they occur close to a community. This plays out in the economics of strengthening older structures where the benefits of avoided building damage and contents losses through retrofit for earthquake are not a full offset for the significant costs.\  Other avoided costs associated with business losses, lost wages, health care costs, and the value placed on human life, do increase the sum significantly but are not realised by the property owner. While not all avoided costs were considered, this project indicates that the justification for retrofit based solely on a financial investment may be difficult to demonstrate for URM buildings in Melbourne.

As was also illustrated by the earlier York study, there are other considerations for the retrofit of URM buildings in the Melbourne CBD and in other older business districts in the city. If a rare earthquake occurred locally during a period of high public exposure there would be considerable loss of life. This research has shown that if a 5,000 year Return Period (RP) event (5.5 Mw) occurring on a business day approximately 100 people would die with close parallels to the 2011 Christchurch Earthquake outcome for masonry structures (42 fatalities). This may point to cheaper levels of retrofit with the objective of tying back elements that could cause casualties, rather than having the aim of avoiding economic loss.

Further, following a rare, but credible, earthquake high value heritage buildings would be lost. The research has shown that the willingness to pay by just the residents of the City of Melbourne LGA adds a notional 10\% of the total benefits of the mitigation program.

SUMMARY

The project has applied a range of retrofit measures for a suite of six URM building types developed as part of Project A9 to a very large population of URM building found in the Melbourne CBD. 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 project has also demonstrated the benefit of retrofit through a virtual retrofit of a major city CBD. These benefits include reduced post event logistics for emergency management and the local government, reducing financial losses to building owners, businesses, and reducing injuries and fatalities. It has also demonstrated that retrofit reduces the long term financial cost of earthquake hazard, thereby making risk transfer through insurance uptake more affordable. Finally, it has demonstrated how valuable heritage structures can be progressively preserved for the future by protecting them from future credible earthquakes.

}, keywords = {buildings, earthquake, Melbourne, mitigation, risk, strategy}, issn = {707}, author = {Hyeuk Ryu and Martin Wehner and Jaroslav Vaculik and Valdis Juskevics and Mark Edwards and Michael Griffith and Itismita Mohanty and Stuart Butt and Neil Corby and Trevor Allen and Robert Hewison} } @article {bnh-7922, title = {Improving the resilience of existing housing to severe wind events - final project report}, number = {656}, year = {2021}, month = {03/2021}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

This BNHCRC project titled:\  Improving the resilience of existing housing to severe wind events prescribes practical structural retrofits that will make improvements to the performance of Pre-80s (Legacy) houses in windstorms as well as measures to reduce damage and loss to contemporary houses.

Damage investigations carried out by the Cyclone Testing Station (CTS) following severe windstorms have typically shown that houses built prior to the mid-1980s in Australia perform worse than houses constructed to contemporary building standards, during windstorms. Given that these older houses are a significant proportion of the housing stock, practical structural upgrading based on the latest research may improve performance of housing and the economic and social wellbeing of a community.

Some details for structural retrofitting currently exist, but their uptake is limited, and there is also evidence that these are not carried out when houses require repairs following severe storms. Therefore, the issues of retrofitting legacy housing, including feasibility and benefit-cost are analysed in this project.

The primary objective of this study was to identify vulnerable legacy house types across Australia and develop cost-effective retrofits for mitigating damage during windstorms. These evidence-based strategies will (a) aid policy formulation and decision making by Government and industry, and (b) provide guidelines detailing various options and benefits to homeowners and the industry for retrofitting typical at-risk houses in Australia. The main aims were to:

This report presents an overview of the research approach used for this project including the selection of house types, the development of the VAWS software and the Internet-based guidelines. A case study is presented of the vulnerability and benefit cost assessment of one of the selected house types, with the complete set of results presented in the Appendices. These results show that tile roofed houses in cyclonic regions of Australia benefit the most from retrofitting for severe wind events. The benefit-cost ratios for these tile roof houses and other house types are expected to improve when accounting for intangible costs, which are currently not included in the analyses presented in this report. In addition, examples of the impacts and utilisation of this project including the Queensland Government Housing Resilience Program are also presented.

}, keywords = {cyclone, events, existing housing, resilience, severe, wind}, issn = {656}, author = {John Ginger and Korah Parackal and David Henderson and Martin Wehner and Hyeuk Ryu and Mark Edwards} } @article {bnh-6901, title = {Cost-effective mitigation strategy development for building related earthquake risk}, number = {565}, year = {2020}, month = {05/2020}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

The CRC project Cost-effective mitigation strategy development for building related earthquake risk\ is seeking to address the need for an evidence base to inform decision making on the mitigation of the earthquake risk posed by vulnerable Australian buildings. It aims to develop information related to more vulnerable Australian building types in the following areas:-

This report describes progress made against the last component which undertook some trial runs to estimate business income loss and rental income loss and provided a complete work plan for estimating direct health care cost.

The economic loss modelling approach aims to encompass the information needs of a range of decision makers. These view benefits through different {\textquotedblleft}lenses{\textquotedblright} and at differing scales. For this research they include:-

This report presents the methodological progress in estimating the proprietary and wage/salary income loss due to business interruption, direct health care costs and the casualty costs to society due to injury and loss of life in the context of the forthcoming Melbourne city case study. The report corresponds with the 30 June 2019 project milestone deliverable {\textquotedblleft}Reporting on Economic Evaluation of Mitigation Strategies and Building Level{\textquotedblright}.

}, keywords = {buildings, cost-effective, earthquake risk, mitigation strategy}, issn = {565}, author = {Itismita Mohanty and Mark Edwards and Hyeuk Ryu and Martin Wehner} } @article {bnh-7186, title = {Earthquake mitigation of WA regional towns: York case study - final report}, number = {596}, year = {2020}, month = {08/2020}, institution = {Bushfire and Natural Hazards CRC}, address = {MELBOURNE}, abstract = {

Earthquake hazard was only fully recognised for Australian building design in the early 1990{\textquoteright}s following the Newcastle Earthquake of 1989. This has resulted in a significant legacy of Australian buildings that are inherently more vulnerable to low to moderate earthquake generated ground motion. Having accessible knowledge of the most effective measures to retrofit older masonry buildings will enable and encourage the strengthening of buildings resulting in more resilient communities.

Western Australia has a region of elevated seismicity inland from Perth where there are located several older regional towns having a predominance of older unreinforced masonry (URM) buildings. In 1968 the town of Meckering was devastated by an earthquake (Gordon et al, 1980), which destroyed the town{\textquoteright}s URM building stock and damaged URM buildings in other neighbouring towns. The town of York, situated approximately 37km from the epicentre was also significantly damaged (Everingham et al, 1982). The combination of high hazard and vulnerability in this region points to a need for informed mitigation measures.

This project entailed undertaking a mitigation implementation study of York, Western Australia{\textquoteright}s oldest inland town, which has many valuable historical buildings that are vulnerable to damage by a large earthquake. This utilisation project sits beneath and draws upon the vulnerability and economic modelling research outcomes of the BNHCRC project {\textquotedblleft}Cost-effective Mitigation Strategy Development for Building related Earthquake Risk{\textquotedblright}. Utilising the outcomes of the project a range of mitigation strategies have been virtually applied to the town{\textquoteright}s URM buildings. This has enabled an assessment of the effectiveness of these interventions on community risk and emergency management (EM) logistics in the context of rare, but credible, earthquakes.

In this report the research and its outcomes are presented and discussed. Further, recommendations are made for future retrofit strategy implementation in York and more broadly in Western Australia. In particular, a new NDRP project is described that will build upon this BNHCRC project in testing the application of the measures in actual retrofit work undertaken in York. This BNHCRC project has been led by the University of Adelaide (UoA) with project partner Geoscience Australia (GA). The end users are the Shire of York and the WA Department of Fire and Emergency Services (DFES) with valuable contributions made by the WA Department of Planning, Lands and Heritage. Through the workshop activity reported there have also been valuable guidance from Engineering Heritage, WA, and the Insurance Australia Group (IAG).

}, keywords = {earthquake, mitigation, regional towns, york}, issn = {596}, author = {Martin Wehner and Hyeuk Ryu and Michael Griffith and Mark Edwards and Neil Corby and Itismita Mohanty and Jaroslav Vaculik and Trevor Allen} } @article {bnh-7300, title = {Improving the resilience of existing housing to severe wind events: annual report 2019-2020}, number = {607}, year = {2020}, month = {09/2020}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

This BNHCRC project titled:\  Improving the resilience of existing housing to severe wind events prescribes practical structural retrofits that will make improvements to the performance of Pre-80s (Legacy) houses in windstorms as well as measures to reduce damage and loss to modern homes.

The major activity carried out in 2019-20 by the CTS-JCU and GA has been refining the VAWS software package using detailed wind loading and structural response test data and conducting a benefit-cost analysis for a range of retrofit or mitigation options:\ 

The retrofit options for the ten selected house types are also being provided as guideline in a website that is being produced. In line with the project timeline, an alpha version of this tool will be presented to Stakeholders in the next Quarter with the intention of having the final version released at the end of the project.

This project continues to give advice to the Queensland Government Household Resilience Program which provides funding to low income eligible home owners to improve the resilience of their homes against cyclones. This program managed by the Queensland Department of Housing \& Public Works (QDHPW) commenced in late 2018 and has been extended through 2020. Eligible home owners can apply to receive a Queensland Government grant of 75\% of the cost of improvements (up to a maximum of $11,250 including GST. About 1700 houses have been retrofitted so far.\ 

}, keywords = {Housing, resilience, severe wind}, issn = {607}, author = {Korah Parackal and Martin Wehner and John Ginger and Hyeuk Ryu and David Henderson and Mark Edwards} } @article {bnh-6782, title = {Progress report on case study CBD precinct}, number = {552}, year = {2020}, month = {03/2020}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

The CRC Project A9 entitled {\textquotedblleft}Cost-Effective Mitigation Strategy Development for Building Related Earthquake Risk{\textquotedblright} is seeking to address the need for an evidence base to inform decision making on the mitigation of the earthquake risk posed by vulnerable Australian buildings. It aims to develop information related to more vulnerable Australian building types in the following areas:

This project also includes a case study to demonstrate the utility of the research with central Melbourne identified as the locality. Central Melbourne has a concentration of older unreinforced masonry buildings so the case study will examine the current risk posed by these and how they can be mitigated through application of the measures developed in this CRC project. Significantly this project will link to the concluding utilisation project on York and will integrate research outcomes on heritage value to be developed by the CRC project {\textquotedblleft}Economics of Natural Hazards{\textquotedblright} led by the University of Western Australia. This progress report describes the scope, the research elements and status of these, and the process by which they are being integrated into the final research outcomes. It also provides background to a requested variation to delay the final deliverable and associated CRC payment to enable other research outputs to be integrated.

This report corresponds with the 30 September 2019 project milestone deliverable {\textquotedblleft}Progress Report on Case Study CBSD Precinct{\textquotedblright}, BNHCRC reference 3.1.2.

}, keywords = {buildings, cbd, Decision making, earthquake risk, mitigation}, issn = {552}, author = {Hyeuk Ryu and Martin Wehner and Mark Edwards and Itismita Mohanty} } @article {bnh-5433, title = {Cost-Effective Mitigation Strategy Development for Building Related Earthquake Risk Annual Report 2017-2018}, number = {464}, year = {2019}, month = {03/2019}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {
This project arose out of the on-going research efforts by the group involving\ structural engineering academics at the Universities of Adelaide, Melbourne and\ Swinburne with Geoscience Australia experts all working towards seismic risk\ reduction in Australia. Most of the research team are actively involved in the\ revision to the Australian Earthquake Loads standard (AS1170.4) as well as being\ members of the Australian Earthquake Engineering Society which is a Technical\ Society of Engineers Australia. The devastating impact of the 2010{\textendash}11\ earthquakes in the Christchurch region on the New Zealand economy and\ society has further motivated this group to contribute to this CRC{\textquoteright}s aims of risk\ reduction for all natural hazards in Australia.\ This project addresses the need for an evidence base to inform decision making\ on the mitigation of the risk posed by the most vulnerable Australian buildings\ subject to earthquakes. While the focus of this project is on buildings, many of\ the project outputs will also be relevant for other Australian infrastructure such as\ bridges, roads and ports, while at the\ same time complementing other {\textquoteleft}Natural\ Hazards{\textquoteright} CRC project proposals for severe wind and flood.
}, keywords = {cost-mitigation, earthquake}, author = {Michael Griffith and Hossein Derakhshan and Elisa Lumantarna and Hing-Ho Tsang and John Wilson and Nelson Lam and Mark Edwards and Martin Wehner} } @article {bnh-5480, title = {Cost-effective mitigation strategy development for building related earthquake risk: progress report on economic loss modelling }, number = {472}, year = {2019}, month = {03/2019}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

The CRC Project A9 entitled {\textquotedblleft}Cost-Effective Mitigation Strategy Development for Building Related Earthquake Risk{\textquotedblright} is seeking to address the need for an evidence base to inform decision making on the mitigation of the earthquake risk posed by vulnerable Australian buildings.\  It aims to develop information related to more vulnerable Australian building types in the following areas:-

This report describes progress made against the last component which is directed at economic loss modelling.\  The work has been guided by, and is consistent with, the project team consensus achieved at a single day workshop convened at Swinburne University on the 23rd October 2015.

The economic loss modelling approach aims to encompass the information needs of a range of decision makers.\  These view benefits through different {\textquotedblleft}lenses{\textquotedblright} and at differing scales.\  For this research they include:-

In this report a background is provided on the motivations for this project.\  The current findings of an ongoing literature survey are presented, and the economic modelling frameworks proposed by the project team are described.\  This report corresponds with the Geoscience Australia component of the 30 June 2016 project milestone deliverable {\textquotedblleft}Progress Report on Economic and Damage Loss Models{\textquotedblright}.

}, keywords = {cost-effective, Disaster management, earthquake modelling}, author = {Itismita Mohanty and Mark Edwards and Hyeuk Ryu and Martin Wehner} } @article {bnh-5485, title = {Cost-Effective Mitigation Strategy Development For Flood Prone Buildings: Flood Damage Models For Floodplain Management Workshop}, number = {473}, year = {2019}, month = {03/2019}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

This document reports on the proceedings and outcomes of a flood vulnerability workshop held at RMIT University in Melbourne on 14 June 2018. The workshop was convened as part of a research utilisation project under the Bushfire and Natural Hazards Cooperative Research Centre (BNHCRC) project entitled {\textquoteright}Costeffective mitigation strategy development for flood prone buildings{\textquoteright}. Key workshop aims were to finalise the project scope with key stakeholders, establish a Project Steering and identify case study communities for consideration. The research utilisation project entails working with a variety of stakeholders with the aim of translating detailed flood vulnerability information into practical guidance for flood risk managers. It involves developing and testing a number of resolution options (from asset specific vulnerability assessments to more generalised methods) in a series of case studies. The workshop structure featured presentations and discussion following a logical flow from context setting, scope refinement and consensus through to governance and next steps. The key workshop aims described above were achieved and a series of {\textquoteleft}next steps{\textquoteright} were identified and documented in this report.

}, keywords = {building risk, cost-effective, Flood, flood risk, floodplain}, author = {Dale, K and Maqsood, T and Mark Edwards and Krishna Nadimpalli} } @conference {bnh-6385, title = {Earthquake Management Logistics for York, WA, Pre and Post Mitigation}, booktitle = {Australian Earthquake Engineering Society 2019 Conference}, year = {2019}, month = {12/2019}, address = {Newcastle}, abstract = {

Rare Australian earthquake events can cause extensive damage and present significant logistical challenges for emergency management agencies and local governments. Evidence of this can be seen from recent earthquake events that include the 2010 Kalgoorlie earthquake and the 1989 Newcastle earthquake of 30 years ago. Emergency managers do not experience damaging earthquakes on the same regular basis as storms, floods, and bushfires and therefore don{\textquoteright}t always fully understand the consequences they may face. Scenario modelling can provide insights to inform response and recovery by emergency management and recovery agencies as well as demonstrate how these impacts can be moderated by the retrofit of the most vulnerable building types.

The Shire of York is partnering with the WA Department of Fire and Emergency Services (DFES), the University of Adelaide and Geoscience Australia in a collaborative project that explores the current earthquake risk in the heritage town of York, Western Australia, and how the risk could be moderated through targeted retrofit. The project forms part of the Bushfire and Natural Hazards Cooperative Research Centre project {\textquotedblleft}Cost-effective Mitigation Strategy Development for Building Related Earthquake Risk{\textquotedblright}. This paper describes the approach taken and the predicted consequences modelled for a range of credible earthquake scenarios. Significantly, based on the recommendations from a stakeholder workshop in York on the 9thAugust 2018, it is also assessing how these consequences would be moderated in future decades through two rates of retrofit uptake in the town. This work is informing emergency management planning by DFES and the Shire of York. It is also illustrating the benefits of targeted community level retrofit to address the risk posed by the community building types most vulnerable to earthquakes.

}, keywords = {earthquake, Emergency management, modelling, retrofit, senario}, url = {https://aees.org.au/wp-content/uploads/2019/12/70-Hyeuk-Ryu.pdf}, author = {Hyeuk Ryu and Mark Edwards and Martin Wehner and Stephen Gray and Michael Griffith and Jaroslav Vaculik and Neil Corby and Trevor Allen} } @conference {bnh-6506, title = {Flood vulnerability functions: detailed vs generalised approach }, booktitle = {AFAC19 powered by INTERSCHUTZ - Bushfire and Natural Hazards CRC Research Forum}, year = {2019}, month = {12/2019}, publisher = {Australian Institute for Disaster Resilience}, organization = {Australian Institute for Disaster Resilience}, address = {Melbourne}, abstract = {

Flood vulnerability functions for buildings (often called stage-damage functions) relate flood damage to the depth of inundation in the building. These functions are generally used in assessing flood risk and in evaluating cost-effective mitigation strategies for flood risk management. Flood vulnerability models are usually developed for a certain location by following empirical, analytical or heuristic procedures. They can be developed for a representative building type (detailed approach) or representing a mix of building types (generalised approach).

Geoscience Australia (GA) has developed a suite of flood vulnerability functions for a range of building types (detailed approach) that covers residential, commercial, industrial and community building land use types. These functions are best used in detailed micro level studies and are applicable to the highest resolution of building exposure information with flood vulnerability directly attributed to individual buildings.

This paper describes research with the National Flood Risk Advisory Group (NFRAG), the Australian Institute for Disaster Resilience (AIDR), state and local governments and industry to translate detailed vulnerability information into practical guidance for flood risk managers undertaking studies under the floodplainspecific management process as outlined in the AIDR Handbook, Managing the Floodplain: A Guide to Best Practice in Flood Risk Management.

This research derives generalised vulnerability functions for a mix of building and land use types. The generalised curves can be utilised at meso or macro level study and are intended to be applied at a resolution of built environment information readily available to floodplain managers.

Download the full peer reviewed research proceedings\ from the Bushfire and Natural Hazards CRC Research Forumhere.

}, keywords = {emergency management., Floods, land use, risk management, Vulnerability}, url = {https://knowledge.aidr.org.au/resources/australian-journal-of-emergency-management-monograph-series/}, author = {Maqsood, T and Dale, K and Mark Edwards and Krishna Nadimpalli} } @article {bnh-5432, title = {Impact-Based Forecasting for the Coastal Zone: East Coast Lows- Annual Report 2017/2018}, number = {463}, year = {2019}, month = {03/2019}, pages = {1-28}, type = {Report}, keywords = {Built Environment, Forecasting, Severe Weather}, issn = {463}, author = {Harald Richter and Craig Arthur and Serena Schroeter and Martin Wehner and Jane Sexton and Beth Ebert and Mark Dunford and Jeffrey Kepert and Shoni Maguire and Russell Hay and Mark Edwards} } @article {bnh-6276, title = {Improving the resilience of existing housing to severe wind events - annual report 2018-19}, number = {524}, year = {2019}, month = {12/2019}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

This project will provide practical structural retrofits that will make a significant improvement in the performance of Pre-80s (Legacy) houses to wind loads. The major activity carried out in 2018-19 by the CTS-JCU and GA has been progressing the VAWS software package using wind loading and structural response and other test data:

This project has also provided advice to the Queensland Government Household Resilience Program which provides funding to help eligible home owners improve the resilience of their homes against cyclones. This program is managed by the Queensland Department of Housing \& Public Works (QDHPW) and commenced in late 2018. Eligible home owners can apply to receive a Queensland Government grant of 75\% of the cost of improvements (up to a maximum of $11,250 including GST. About 2000 houses have been retrofitted.

}, keywords = {building resilience, cyclones, Emergency management, engineering, Housing, severe wind, storms, structural design}, issn = {524}, author = {John Ginger and Korah Parackal and Martin Wehner and Hyeuk Ryu and David Henderson and Mark Edwards} } @article {bnh-5434, title = {Improving the resilience of existing housing to severe wind events in Australia Annual Report 2017-2018}, number = {465}, year = {2019}, month = {03/2019}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

This project will propose practical structural upgrading solutions based on the latest research that will make a significant improvement in the performance of Pre-80s (Legacy) houses that are impacted by severe windstorms. The project has analysed existing structural retrofitting details available for some forms of legacy housing and has found that uptake is limited, even when these houses require major repairs following severe storm events. The work carried out in 2017-18 has focussed on developing cost-effective strategies for mitigating damage to housing from severe windstorms. The major activity has been progressing the VAWS software package by Geoscience Australia (GA) using wind loading and structural response data and other test data obtained by the CTS-JCU:

{\textbullet} Residential structures (i.e. Houses) have been categorized into types based on building features that influence windstorm vulnerability using CTS and GA housing survey data. Two house types were selected and incorporated in the VAWS package. The structural response (i.e. damage progression) with increasing wind speed has been modelled and validated. Testing carried out as part of BNHCRC supported thesis projects have provided additional data.

{\textbullet} Retrofit options and cost-benefit modules will be added to the VAWS model by GA and made available for trialling by end users and stakeholders (i.e. homeowners, builders, regulators, insurers). End-users and stakeholders will be asked to evaluate VAWS and suggest amendments and provide feedback on practicality and aesthetics of potential upgrading methods for these house types. Cost effective guides will be developed for vulnerable house types.

{\textbullet} Case studies will be used to evaluate effectiveness of proposed retrofit solutions for risk reduction. Economic assessment using the same case studies will be used to promote (via the stakeholders and end users) uptake of practical retrofit options.

}, keywords = {housing structure, resilience, severe wind}, author = {David Henderson and John Ginger and Daniel Smith and Martin Wehner and Hyeuk Ryu and Mark Edwards} } @conference {bnh-6027, title = {Mitigating earthquake risk in Australia}, booktitle = {2019 Pacific Conference on Earthquake Engineering and Annual NZSEE Conference}, year = {2019}, month = {09/2019}, abstract = {

Earthquake risk is not limited to tectonic plate boundary countries. While less frequent, significant earthquakes can occur in intraplate countries like Australia which can have severe consequences. For Australia this is particularly the case as earthquake hazard has not been recognised in the design of buildings and community infrastructure for most of the country{\textquoteright}s settled history. Significant risks exist where community assets are by their nature inherently vulnerable to strong ground shaking. This paper describes three initiatives that are assisting Australian emergency management, infrastructure managers and local government to prepare for and mitigate these risks.

The first of these highlights how the characteristics of geological hazards differ from severe meteorological hazards. The very non-linear nature of impact severity with longer average recurrence interval earthquakes is demonstrated and how this information is supporting emergency management planning including capacity sharing between Association of Southeast Asian Nations (ASEAN) countries in the region is described. Secondly, the paper describes how this research is developing knowledge of the factors behind the vulnerability of critical infrastructure facilities and the options to mitigate these. The software tool System for Infrastructure Facility Resilience Analysis (SIFRA) is described which enables infrastructure facility components to be examined in the context of physical vulnerability, system criticality, repair cost and restoration time. Finally, a utilisation project of the Bushfire and Natural Hazards CRC working with the local government of York Shire in Western Australia (WA) is described. The project is providing information on the effectiveness of targeted retrofit of the heritage town of York to rare earthquakes and how this action by property owners can be incentivised.

}, keywords = {earthquake, mitigation, Vulnerability}, url = {http://db.nzsee.org.nz/2019/Oral/8C.05\%20Edwards.pdf}, author = {Mark Edwards and Muhamman Rahman and Hyeuk Ryu and Martin Wehner and Neil Corby and Michael Griffith and Jaroslav Vaculik} } @article {bnh-6333, title = {Model for assessing the vulnerability of Australian housing to windstorms - VAWS}, number = {529}, year = {2019}, month = {12/2019}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

Modelling the vulnerability of houses in windstorms is important for insurance pricing, policy-making, and emergency management. Models for Australian house types have been developed since the 1970s, and have ranged from empirical models to more advanced reliability based structural engineering models, which provide estimates of damage for a range of wind speeds of interest. This report describes the development of a software program: Vulnerability and Adaption to Wind Simulation (VAWS), which uses probability based reliability analysis and structural engineering for the loading and response coupled with an extensive test database and field damage assessments to calculate the damage experienced by selected Australian house types.\ \ 

}, keywords = {building resilience, cyclone, Emergency management, engineering, severe wind, wind modelling}, issn = {529}, author = {Korah Parackal and Martin Wehner and Hyeuk Ryu and John Ginger and David Henderson and Mark Edwards} } @conference {bnh-6407, title = {Modelling the vulnerability of a high-set house roof structure to windstorms using VAWS }, booktitle = {Bushfire and Natural Hazards CRC Research Day AFAC19}, year = {2019}, month = {12/2019}, address = {Melbourne}, abstract = {

Modelling the vulnerability of houses in windstorms is important for insurance pricing, policy-making, and emergency management. Vulnerability models for Australian house types have been developed since the 1970s and have ranged from empirical models to more advanced reliability based structural engineering models, which provide estimates of damage for a range of wind speeds of interest. This paper describes recent developments in the engineering based vulnerability modelling software: {\textquoteleft}Vulnerability and Adaption to Wind Simulation{\textquoteright} (VAWS), which uses probability based reliability analysis and structural engineering for the loading and response coupled with an extensive test database and field damage assessments to calculate the damage experienced by selected Australian house types. A case study is presented to demonstrate the program{\textquoteright}s ability to model progressive failures, internal pressurization and debris impact.

}, keywords = {debris, simulation, structures, VAWs, Vulnerability, wind}, url = {https://knowledge.aidr.org.au/resources/australian-journal-of-emergency-management-monograph-series/}, author = {Korah Parackal and Martin Wehner and Hyeuk Ryu and John Ginger and Daniel Smith and David Henderson and Mark Edwards} } @conference {bnh-6384, title = {Modelling the vulnerability of old URM buildings and the benefit of retrofit}, booktitle = {Australian Earthquake Engineering Society 2019 Conference}, year = {2019}, month = {12/2019}, abstract = {

The Shire of York is partnering with the WA Department of Fire and Emergency Services (DFES), the University of Adelaide and Geoscience Australia in a collaborative project that will examine the opportunities for reducing the vulnerability of the township of York to a major earthquake. The project forms part of the Bushfire and Natural Hazards Collaborative Research Centre (BNHCRC) project {\textquotedblleft}Cost-effective Mitigation Strategy Development for Building Related Earthquake Risk{\textquotedblright}. The township of York has a number of valuable historical buildings that contribute greatly to the town{\textquoteright}s economic prosperity and, at the same time, are vulnerable to earthquakes.

One of the benefits of retrofitting an old building is the reduction in physical building repair required following a damaging earthquake. To evaluate this benefit it is necessary to know the vulnerability of the unmitigated building and how this changes following retrofit.

This paper describes the approach taken to quantitatively estimate the vulnerability of unmitigated and retrofitted pre-WW1 unreinforced masonry (URM)buildings typical of the buildings found in York. Challenges in estimating vulnerability are discussed. Vulnerability curves are presented for one of six generic building types subjected to a range of retrofit scenarios and the economic benefit of each retrofit scenario is presented and discussed.

}, keywords = {earthquake, retrofit, URM, Vulnerability}, url = {https://aees.org.au/wp-content/uploads/2019/12/02-Mark-Edwards.pdf}, author = {Mark Edwards and Martin Wehner and Hyeuk Ryu and Michael Griffith and Jaroslav Vaculik} } @conference {bnh-4783, title = {Community strategy development for reducing earthquake risk in Western Australia}, booktitle = {AFAC18}, year = {2018}, month = {09/2018}, publisher = {Bushfire and Natural Hazards CRC}, organization = {Bushfire and Natural Hazards CRC}, address = {Perth}, abstract = {

While the earthquake hazard in Australia is generally low by world standards, its severity does include higher hazard in some regions. This is the case in the Yilgarn region east of Perth as highlighted by the 1968 Meckering Earthquake and the observed seismic activity of the region in the last seventy years. Where building construction has not considered earthquake hazard the risk to communities can be significant. This is an issue for the township of York which is WA{\textquoteright}s oldest inland settlement and has a high proportion of heritage buildings that are vulnerable to earthquake. The presence of high risk buildings of this type is a challenge for local government, emergency management and other government agencies with a role in community recovery after disasters.
In the Bushfire and Natural Hazards CRC (BNHCRC) a project called Cost-effective mitigation strategy development for building related earthquake risk is developing information on cost effective strategies for retrofitting vulnerable buildings. The project scope has been augmented to examine the effectiveness of a range of strategies for addressing high risk structures. This is a collaborative study involving a partnership approach between state and local government along with academic and government researchers under the BNHCRC. The project will utilise the mitigation approaches developed by the CRC within a range of potential roll-out options to virtually retrofit the town of York. The net benefits of each will be assessed considering avoided damage, impacts on occupants, lost rental income, and disruption to business activity and households.
In this presentation the motivation for this collaborative effort will be discussed in the context of an improved understanding of natural hazard risk in WA, the increasing focus on investing in risk mitigation as opposed to response and recovery, and the shared interest of both State and Local government to promote resilience in vulnerable communities. The outcomes of a broad stakeholder workshop convened in York on the 9th August 2018 will be described in which strategies for providing incentives for risk reduction were identified. The importance of risk information in informing property owners and communities is discussed and the need to address their apprehension in addressing vulnerability with heritage listed structures. Finally, the value of broader measures of avoided community impacts beyond the direct monetary in decision making is highlighted and the linkages being made to another BNHCRC project called Economics of natural hazards that will enable intangible (non-market) values to be included in a quantitative manner.

}, author = {Stephen Gray and Paul Martin and Mark Edwards and Michael Griffith and Hossein Derakhshan} } @article {bnh-5199, title = {Cost-effective mitigation strategy development for building related earthquake risk: reporting on economic loss models}, year = {2018}, month = {12/2018}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

This report forms part of the output from Project A9 entitled {\textquotedblleft}Cost-Effective Mitigation Strategy Development for Building Related Earthquake Risk{\textquotedblright} within the Bushfire and Natural Hazards Cooperative Research Centre.

Earthquakes have the potential to cause widespread damage to Australian communities and the economic activity that occurs within them. Recent earthquake events have illustrated this, including the Newcastle Earthquake (1989) and the Kalgoorlie Earthquake (2010). This potential is largely due to the fact that much of the Australian building stock has not been designed nor constructed with adequate consideration of earthquake hazard.\ 

Mitigation intervention is needed to reduce this risk but an evidence base is lacking to inform investment. In particular, there is a need for economic measures of the benefits of retrofit as an offset to the sometimes large costs
of upgrading structures for earthquake. This need exists in many other countries.

As part of this research an extensive literature review has been published to inform the best approach for assessing the costs of business interruption and the losses associated with injury and death. Frameworks have also been developed for a range of Australian decision makers. Decision makers include building owners, owners of both business premises and the business within, local government, state government and national government. The scale of decision making metrics range from individual building level up to business precinct level exposures and the interdependence of building performance within them. The information and models required as inputs into the framework have been identified along with how these will be met, either with outputs from this CRC project, or from other sources.

This report builds on the previous work and provides the experimental estimates for different components of economic loss that might occur in the event of an earthquake scenario. These are specifically business income loss, rental income loss and health care expenditure. The report considers these in the context of the future Greater Melbourne region (excluding Mornington Peninsula) as a case study.\ 

Current research on the economic loss modelling is on track. Future work will estimate the actual business interruption loss values for assessing precinct level economic activity disruption.

}, issn = {435}, author = {Itismita Mohanty and Mark Edwards and Hyeuk Ryu and Martin Wehner} } @conference {bnh-4792, title = {Impact-based forecasting for the coastal zone}, booktitle = {AFAC18}, year = {2018}, month = {09/2018}, publisher = {Bushfire and Natural Hazards CRC}, organization = {Bushfire and Natural Hazards CRC}, address = {Perth}, abstract = {

Strong surface wind gusts and heavy rain are meteorological hazards that are predominantly produced by storms such as east coast lows, tropical cyclones or thunderstorms. Interest in these hazards from a response agency point of view lies in their impact on the natural and built environment. At present, weather forecast models still predict mostly {\textquoteright}raw{\textquoteright} meteorological output such as surface wind speeds at certain times, or rain accumulations over a specified period. This model output needs to be combined with exposure and vulnerability information to translate the forecast hazard into predicted impact.

The Bushfire and Natural Hazards CRC project Impact-based forecasting for the coastal zone: East-Coast Lows attempts to demonstrate a pilot capability to deliver impact forecasts for residential housing from an ensemble of weather prediction models runs. The project is a collaborative effort between the Australian Bureau of Meteorology and Geoscience Australia.

The project is initially focusing on the wind and rainfall impact from the 20-22 April 2015 east coast low event in NSW. The wind and rainfall hazard data are provided by a 24-member ensemble of the ACCESS model on a 1.3 km grid, with damage data acquired from NSW State Emergency Services (SES) and the Emergency Information Coordination Unit (EICU) for the 2015 event.

We will show that the multi-hazard nature of an east coast low event makes attributing the observed building damage to a single hazard difficult. Wind damage to residential housing in this case is largely due to tree fall. This {\textquoteright}damage-byintermediary{\textquoteright} mechanism requires not just the knowledge of building properties in an exposed area, but also additional knowledge of the surrounding vegetation and its response to strong winds. We will discuss enhancements to the SES/EICU damage survey templates that would lead to improvements in the development of the hazard-damage relationships.

}, author = {Harald Richter and Craig Arthur and Serena Schroeter and Martin Wehner and Jane Sexton and Beth Ebert and Mark Dunford and Jeffrey Kepert and Shoni Maguire and Russell Hay and Mark Edwards} } @article {bnh-4212, title = {Cost-effective mitigation strategy for building related earthquake risk: annual project report 2016-17}, number = {348}, year = {2017}, month = {09/2017}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

The 1989 Newcastle Earthquake caused damage to 70,000 properties, with an associated total economic loss of AU$ 4 billion. Consistently, the insurance industry has estimated the economic risk posed by a moderate earthquake in any of the capital cities in Australia to be of the order of billions of dollars. A major reason for this risk is that Australia has not designed buildings for earthquake-induced forces until 1995 so that a large portion of our building stock is seismically vulnerable.

As demonstrated in Christchurch, New Zealand, in 2010-11, a magnitude 6 earthquake can have a devastating impact on a city and country (damage rebuild estimated at ~ 20\% national GDP!) even though buildings there have been designed for earthquakes for many decades.

This project includes collaborative research from 4 partner institutions to establish:

  1. The relative vulnerabilities to earthquake shaking of the most common forms of building construction in Australia;
  2. What earthquake retrofit techniques worked and what didn{\textquoteright}t as a starting point in developing a {\textquoteleft}menu{\textquoteright} of economically feasible seismic retrofit techniques that could be used in Australian cities;
  3. With industry end-user support, conduct proof of concept tests on some of the most promising seismic retrofit techniques on buildings scheduled for demolition by the SA state government;
  4. Use the new damage and economic loss models developed over the first 3 years of this project to undertake a seismic risk assessment case study of the Melbourne metro area; and
  5. Advance a series of end user focused research utilization projects in the areas of improved building regulation, community risk reduction, design profession guidance and insurance industry engagement with their policy holders. These will include an Earthquake Mitigation Case Study for the historic town of York in Western Australia and Development of a Rapid Visual Screening procedure for Australian buildings

Finally, using the new damage loss models and costings for seismically retrofitting buildings, make recommendations for the development of seismic retrofit guidelines and policy based on the strong evidence base developed.

}, issn = {348}, author = {Michael Griffith and Hossein Derakhshan and Elisa Lumantarna and Hing-Ho Tsang and Helen M. Goldsworthy and John Wilson and Nelson Lam and Mark Edwards} } @article {bnh-3798, title = {Cost-effective mitigation strategy for building related earthquake risk: final report on economic loss modelling}, number = {246}, year = {2017}, month = {07/2017}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

This report forms part of the output from the Cost-Effective Mitigation Strategy Development for Building Related Earthquake Risk project within the Bushfire and Natural Hazards Cooperative Research Centre.

Earthquakes have the potential to cause widespread damage to Australian communities and the economic activity that occurs within them. Recent earthquake events have illustrated this, including the Newcastle Earthquake (1989) and the Kalgoorlie Earthquake (2010). This potential is largely due to the fact that much of the Australian building stock has not been designed nor constructed with adequate consideration of earthquake hazard.

Mitigation intervention is needed to reduce this risk but an evidence base is lacking to inform investment. In particular, there is a need for economic measures of the benefits of retrofit as an offset to the sometimes large costs of upgrading structures for earthquake.

This need exists in many other countries. As part of this research a literature survey of research published internationally is underway to inform the best approach for assessing the costs of business interruption and the losses associated with injury and death. The findings of this work to date are described and are informing the research program.

This report also describes the frameworks developed for a range of Australian decision makers. Decision makers include building owners, owners of both business premises and the business within, local government, state government and national government. The scale of decision making metrics range from individual building level up to business precinct level exposures and the interdependence of building performance within them. The information and models required as inputs into the framework have been identified along with how these will be met, either with outputs from this CRC project, or from other sources.

The research on the economic loss modelling has produced a functional model. Future work will add refinements to the model such as casualty cost modules adapted from published material. In the succeeding year business interruption loss models will be developed and framework/methodology developed for assessing precinct level economic activity disruption.

}, issn = {246}, author = {Itismita Mohanty and Mark Edwards and Hyeuk Ryu and Martin Wehner} } @article {bnh-4216, title = {Improving the resilience of housing to severe wind events: annual project report 2016-17}, number = {342}, year = {2017}, month = {09/2017}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

Damage investigations carried out by the Cyclone Testing Station (CTS) following severe wind storms have typically shown that Australian houses built prior to the mid-1980s do not offer the same level of performance and protection during windstorms as houses constructed to contemporary building standards. Given that these older houses will represent the bulk of the housing stock for many decades, practical structural upgrading solutions based on the latest research will make a significant improvement to housing performance and to the economic and social well-being of the community.

Structural retrofitting details exist for some forms of legacy housing but the uptake of these details is limited. There is also evidence that retrofitting details are not being included into houses requiring major repairs following severe storm events, thus missing the ideal opportunity to improve resilience of the house and community. Hence, the issues of retrofitting legacy housing, including feasibility and hindrances on take-up, etc., must be analysed.

The primary objective of this research is to develop cost-effective strategies for mitigating damage to housing from severe windstorms across Australia. \ These evidence-based strategies will be (a) tailored to aid policy formulation and decision making in government and industry, and (b) provide guidelines detailing various options and benefits to homeowners and the building community for retrofitting typical at-risk houses in Australian communities. Specific task items include:

}, issn = {342}, author = {David Henderson and Daniel Smith and John Ginger and Martin Wehner and Hyeuk Ryu and Mark Edwards} } @article {bnh-3861, title = {Launceston flood risk mitigation assessment - June 2016 floods: suburb of Newstead}, number = {339}, year = {2017}, month = {10/2017}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

Launceston is floodprone and located within the Tamar River floodplain at the confluence of the Tamar, North Esk and South Esk Rivers in Tasmania. Launceston has been subjected to 35 significant floods since records began, with the 1929 flood considered to be the worst (Fullard, 2013). A new Launceston Flood Authority was established in 2008 to design, construct and maintain existing and new flood levees. To replace the existing deteriorated levees a flood mitigation initiative was completed in 2016 to provide Launceston with reliable flood protection up to the 200 year Annual Recurrence Interval (ARI) event (Fullard, 2013).

However, this flood mitigation initiative did not extend to Newstead, a suburb in the east of Launceston, with the suburb consequently not protected from floods. Therefore, a new levee was proposed to protect the properties in Newstead from future floods. The cost of the proposed levee was estimated to be $580,000 along with an annual maintenance cost of $10,000 (Fullard, 2016).

Geoscience Australia was funded to undertake a project to conduct a Cost Benefit Analysis (CBA) of the proposed flood levee in Newstead as a variation to its current project (BNHCRC, 2017a) within the Bushfire and Natural Hazards CRC (BNHCRC). The project stakeholders included the CRC, Tasmanian Department of Premier and Cabinet, Tasmanian State Emergency Service, the City of Launceston, Launceston Flood Authority and Northern Midlands Council.

This report provides the details of the CBA of the proposed flood levee along with consideration of several other mitigation options as researched within the BNHCRC flood mitigation project.

}, isbn = {978-0-9941696-8-6}, issn = {339}, author = {Maqsood, T and Martin Wehner and Itismita Mohanty and Neil Corby and Mark Edwards and Fiona L Gibson and Rogers, Michael J.} } @article {bnh-3803, title = {Launceston flood risk mitigation - June 2016 floods}, number = {257}, year = {2017}, month = {10/2017}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

With Launceston experiencing severe flooding in June 2016, this project reviewed the costs and benefits of mitigation work (upgraded levees) which began in 2010. Flood mitigation is an expensive exercise, and this research highlights the benefits through avoided impacts of the flood levee mitigation program, against the cost of construction.

Findings show that the upgrading of the levee system, completed in 2014, resulted in avoiding losses of about $216 million (had the pre-existing levees failed), which is approximately four times the total investment in the new levee system. This investment in building the new levee system was found to be a sound economic decision based on the estimated costs at the time of decision making, alongside improved estimates of benefits from this study. The actual benefits of these mitigation works to the community extend beyond the direct benefits as assessed in this project, to the intangible and indirect benefits that have not been included.

It was found that sea level rise scenarios would only have a limited impact on building losses. However, the combined impact of sea level rise and increased rainfall intensity due to climate change on the total losses may be significantly greater and could be further investigated.

The study assessed:

}, isbn = {978-0-9941696-7-9}, issn = {257}, author = {Maqsood, T and Martin Wehner and Itismita Mohanty and Neil Corby and Mark Edwards} } @article {bnh-4148, title = {Testing of simulated flood effect on the strength of selected building components}, number = {334}, year = {2017}, month = {06/2017}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

This report presents the results of tests conducted to ascertain the resilience of selected building components to floodwater exposure. The experimental test programme was part of the Bushfire and Natural Hazards Collaborative Research Centre (BNHCRC) project entitled {\textquotedblleft}Cost-effective mitigation strategy development for flood prone buildings{\textquotedblright}.

The motivation for this project arises from the experience and observations made during the recent flooding in Australia in 2011 and 2013, which caused widespread devastation in Queensland. The objective of the project is to address the vulnerability of existing residential building stock in Australian floodplains and is targeted at assessing cost-effective mitigation strategies to reduce the vulnerability.

Geoscience Australia as the lead researcher for the project selected the Cyclone Testing Station at James Cook University in Townville, Queensland, to conduct the experimental tests. These tests aimed to address knowledge gaps in the areas of strength and durability implications of selected components of a typical brick veneer slab-on-grade house due to immersion.

The experimental programme was developed in consultation with insurance industry loss assessors from two major companies and was scoped in recognition of the available budget. The objective of the testing was to identify whether the selected components remain serviceable following inundation and subsequent drying or whether replacement was required.

The experimental programme examined the resistance to inundation of three common building components as outlined below. For each component, a number of samples were tested to attempt to provide some understanding of the variation of resistance. For each component some specimens were tested dry without wetting and some were tested after drying following inundation. For Component 3, some specimens were also tested wet immediately after inundation.

The results of the tests showed that flooding did not have any significant effect on the pull-out strength of the bond of the ceramic floor and wall tiles to their substrate, nor on the racking strength of the OSB wall sheet bracing. There was a nominal strength reduction of 10\% for the HDF wall sheet bracing when tested after wetting and drying cycle.

However, there was a significant reduction (~46\%) in load carrying capacity of the timber joists when tested in the wet condition. These results suggest that the samples whilst in the wet stage may be compromised due to reduced strength capacity and stiffness. However, if allowed to dry then the specimen could recover to nominally 96\% of average strength capacity and stiffness. Moreover, it was observed that the moisture content level after the test returned close to pre-inundation level within a week and therefore contributed to recover the strength and stiffness.

The results of the testing will inform recommendations on mitigation measures within the BNHCRC flood project. The results will also inform the selection of building materials for new construction in flood-prone areas.

}, issn = {334}, author = {Maqsood, T and Martin Wehner and Mark Edwards and Simon Ingham and David Henderson} } @article {bnh-3421, title = {Cost-effective mitigation strategies for residential buildings in Australian flood plains}, journal = {International Journal of Safety and Security Engineering}, volume = {6}, year = {2016}, pages = {550-559}, chapter = {550}, abstract = {

In recent years, floods have impacted many Australian communities. The floods have resulted in significant logistics for emergency management and considerable costs to all levels of government and property owners to undertake damage repair and enable community recovery.

These impacts are fundamentally the result of inappropriate development on floodplains and a legacy of high risk building stock in flood-prone areas. The Australian Bushfire and Natural Hazards Collaborative Research Centre project entitled {\textquotedblleft}Cost-effective mitigation strategy development for flood-prone buildings{\textquotedblright} aims to address this issue and is targeted at assessing mitigation strategies to reduce the vulnerability of existing residential building stock in Australian floodplain area.

This paper presents the outcomes of this ongoing project. Key tasks of the project include: (1) a classification of residential building stock, (2) a review of flood mitigation strategies, (3) vulnerability assessment of typical building types with and without mitigation, and (4) benefit cost analyses of all retrofit options for a range of severity/likelihood of flood hazard covering a selection of catchment types. The work will provide information on the optimal retrofit strategies in the context of Australian construction costs and catchment characteristics.

The research will also entail experimental testing of preferred materials to ascertain their resilience to flood water exposure. The outcome of this research will be an evidence base to inform decisions about mitigating the risk posed by buildings on floodplains. The information will be targeted to all levels of government, insurance industry and private property owners.

}, doi = {10.2495/SAFE-V6-N3-550-559}, url = {https://www.witpress.com/elibrary/sse-volumes/6/3/1349}, author = {Maqsood, T and Martin Wehner and Dale, K and Mark Edwards} } @conference {bnh-2953, title = {Development of flood mitigation strategies for Australian residential buildings}, booktitle = {AFAC16}, year = {2016}, month = {08/2016}, publisher = {Bushfire and Natural Hazards CRC}, organization = {Bushfire and Natural Hazards CRC}, address = {Brisbane}, abstract = {

Globally floods cause widespread damage and loss of life and property. An analysis of global statistics conducted by Jonkman (2005) showed that floods (including coastal flooding) caused 175,000 fatalities and affected more than 2.2 billion people between 1975 and 2002. In Australia, floods cause more damage on an average annual basis than any other national disaster (HNFMSC, 2006). The fundamental causes of this severity of damage and the key factors contributing to flood risk, in general, are the vulnerable buildings constructed within floodplains and land-use planning.\ Recent events in Australia (2011, 2013 and 2015) highlighted the vulnerability of housing to flooding which originates from inappropriate development in floodplains. While there is a construction standard issued by the Australian Building Code Board (ABCB, 2012) for new construction in some types of flood-prone areas, a large proportion of the existing building stock has been built in flood-prone areas across Australia (HNFMSC, 2006). Flood losses from the recent events highlight the requirement of implementing effective and efficient mitigation measures to reduce losses in future.

}, author = {Maqsood, T and Martin Wehner and Dale, K and Mark Edwards} } @article {bnh-3087, title = {Improving the resilience of existing housing to severe wind events: Annual project report 2015-2016}, number = {224}, year = {2016}, month = {09/2016}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

Damage investigations carried out by the Cyclone Testing Station (CTS) following severe wind storms have typically shown that Australian houses built prior to the mid-1980s do not offer the same level of performance and protection during windstorms as houses constructed to contemporary building standards. Given that these older houses will represent the bulk of the housing stock for many decades, practical structural upgrading solutions based on the latest research will make a significant improvement to housing performance and to the economic and social well-being of the community.

Structural retrofitting details exist for some forms of legacy housing but the uptake of these details is limited. There is also evidence that retrofitting details are not being included into houses requiring major repairs following severe storm events, thus missing the ideal opportunity to improve resilience of the house and community. Hence, the issues of retrofitting legacy housing, including feasibility and hindrances on take-up, etc., must be analysed.

The primary objective of this research is to develop cost-effective strategies for mitigating damage to housing from severe windstorms across Australia.\  These evidence-based strategies will be (a) tailored to aid policy formulation and decision making in government and industry, and (b) provide guidelines detailing various options and benefits to homeowners and the building community for retrofitting typical at-risk houses in Australian communities. Specific task items include:

{\textbullet} \  Categorise residential structures into types based on building features that influence windstorm vulnerability using Geoscience Australia and CTS survey data. From these, a suite will be selected to represent those contributing most to windstorm risk

{\textbullet} \  Involve end-users and stakeholders (i.e. homeowners, builders, regulators, insurers) to assess amendments and provide feedback on practicality and aesthetics of potential upgrading methods for a range of buildings. Cost effective strategies will be developed for key house types

{\textbullet} \  Vulnerability models will be developed for each retrofit strategy using survey data, the authors{\textquoteright} existing vulnerability models, and the NEXIS database of Australian housing characteristics. Case studies will be used to evaluate effectiveness of proposed retrofit solutions in risk reduction. Economic assessment using the same case studies will be used to promote uptake of practical retrofit options.

}, issn = {224}, author = {Daniel Smith and David Henderson and John Ginger and Martin Wehner and Hyeuk Ryu and Mark Edwards} } @article {bnh-2702, title = {Preliminary report on economic loss modelling}, number = {164}, year = {2016}, month = {05/2016}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

This report forms part of the output from entitled {\textquotedblleft}Cost-Effective Mitigation Strategy Development for Building Related Earthquake Risk{\textquotedblright} within the
Bushfire and Natural Hazards Cooperative Research Centre.


Earthquakes have the potential to cause widespread damage to Australian communities and the economic activity that occurs within them. Recent earthquake events have illustrated this, including the Newcastle Earthquake (1989) and the Kalgoorlie Earthquake (2010). This potential is largely due to the fact that much of the Australian building stock has not been designed nor constructed with adequate consideration of earthquake hazard.
Mitigation intervention is needed to reduce this risk but an evidence base is lacking to inform investment. In particular, there is a need for economic measures of the benefits of retrofit as an offset to the sometimes large costs of upgrading structures for earthquake.


This need exists in many other countries. As part of this research a literature survey of research published internationally is underway to inform the best approach for assessing the costs of business interruption and the losses associated with injury and death. The findings of this work to date are described and are informing the research program.


This preliminary report also describes the frameworks developed for a range of Australian decision makers. Decision makers include building owners, owners of both business premises and the business within, local government, state government and national government. The scale of decision making metrics range from individual building level up to business precinct level exposures and the interdependence of building performance within them. The information and models required as inputs into the framework have been identified along with how these will be met, either with outputs from this CRC project, or from other sources.


Current research on the economic loss modelling is on track. Future work will complete the literature survey and develop casualty cost modules adapted from those published for use in this project. In the succeeding year business interruption loss models will be developed and framework/methodology developed for assessing precinct level economic activity disruption.

}, issn = {164}, author = {Mark Edwards and Itismita Mohanty and Hyeuk Ryu and Martin Wehner} } @article {bnh-1537, title = {Cost-Effective Mitigation Strategy Development for Flood Prone Buildings Annual Report 2014}, year = {2015}, abstract = {

This annual report has been completed as a component of the Cost-Effective Mitigation Strategy Development for Flood Prone Buildings project.\ 

}, author = {Maqsood, T and Martin Wehner and Mark Edwards and Dale, K} }