@article {bnh-5494, title = {Analysis of damage surveys of houses and preliminary input of VAWs}, number = {477}, year = {2019}, month = {04/2019}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

Significant financial loss in terms of cost of rebuilding or repair and loss of function of property (e.g. commercial activity, rental, relocation of residents, etc.), has been documented following recent severe tropical cyclones impacting the Australian coastal communities. These damage investigations estimate that the wind speeds in these events were less than the Australian building standard{\textquoteright}s design level wind speed for the regions impacted. Analysis of insurance claims data highlights issues with wind driven rain water damage. Additionally, investigations of the damaged buildings along with analysis of claims data reveals a high proportion of the losses are associated with contemporary construction as opposed to pre-current code buildings.\ 

Education and awareness of consequences of such failures (e.g. damage to property and risk to life) is required in all steps of the building process (regulation, design, construction, certification and maintenance) and by all parties (designer, builder, certifier, and owner).

}, keywords = {building risk, resilience, severe wind, VAWs}, author = {David Henderson and Daniel Smith and Korah Parackal and John Ginger} } @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-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-4790, title = {Large damage bills to buildings from cyclones can be reduced by small actions}, booktitle = {AFAC18}, year = {2018}, month = {09/2018}, publisher = {Bushfire and Natural Hazards CRC}, organization = {Bushfire and Natural Hazards CRC}, address = {Perth}, abstract = {

Recent severe tropical cyclones and storms impacting Australian cities and towns have resulted in large financial losses due to damaged buildings and property. Disruption to livelihoods during the repair/rebuilding prolongs recovery for the community. Damage investigations by the Cyclone Testing Station estimate the wind speeds for the majority of the regions investigated were less than the design wind speeds for contemporary construction (i.e. for buildings less than 35 years old). The damage building assessments show a significant proportion of the losses are due to contemporary buildings. This raises issues as to appropriateness of our building construction, Codes, engineering design practices, and ongoing maintenance.

}, author = {David Henderson and Daniel Smith and John Ginger} } @article {bnh-5162, title = {Analysis of rapid damage assessment data following severe windstorm events}, journal = {Australian Journal of Emergency Management}, volume = {32}, year = {2017}, month = {10/2017}, abstract = {

The Cyclone Testing Station (CTS) and partners have conducted forensic damage assessments in Australia following severe windstorm events for over four decades. The information collected is used for building science research that provides the evidence base needed for improvements to building codes and development of damage mitigation solutions. The Queensland Fire and Emergency Services (QFES) operate Rapid Damage Assessment (RDA) teams in the aftermath of major disasters (e.g. cyclone and bushfire) to collect and disseminate information on extent of damage to buildings in impacted communities. These data enables focused and coordinated response in the immediate aftermath of an event and better planning for event recovery. This paper explores the use of QFES RDA datasets in analysing the damaging effects of severe windstorm events. Two case studies are discussed: a supercell that hit Brisbane on 27 November 2014 and Tropical Cyclone Debbie that made landfall along the northern Queensland coastline in March 2017. Where possible, damage data are combined with hazard information (dual-Doppler radar horizontal wind fields) and their relationship is investigated. The analysis demonstrates that RDA data are not only useful in response and recovery phases, but also have value for research aiming to better understand building failures and reduce damage in future events.

}, url = {https://ajem.infoservices.com.au/items/AJEM-32-04-21}, author = {Daniel Smith and Richard Krupar III and David Henderson and M. S. Mason} } @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-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-5101, title = {Investigating a wind tunnel method for determining wind-induced loads on roofing tiles}, journal = {Journal of Wind Engineering and Industrial Aerodynamics}, volume = {155}, year = {2016}, month = {08/2016}, pages = {47-59}, chapter = {47}, abstract = {

Current design loads for roofing tile systems in the U.S. are determined based on a standardized wind tunnel testing method developed in the 1990s to examine wind-induced pressures on the upper and lower surfaces of the tile. The method neglects several key parameters that are well known to affect wind loading (e.g. wind angle, specimen shape, etc.). The research objective of this study is to investigate this method by [1] characterizing wind-induced surface pressure distributions on field tiles for varying wind angles of attack and [2] measuring load path intensity through mechanically fastened tile attachments. Surface pressure distributions were measured on three full-size, rapid prototyped roofing tile models with 256 pressure taps immersed in wind flows. The models are geometrically identical to low-, medium- and high-profile concrete roofing tiles that are widely used in high wind areas. Additionally, their real counterparts were instrumented with load cells to measure reaction forces at mechanical fasteners. The results highlight areas of the method that are lacking in specificity and shows that low-resolution pressure measurement may yield conservative parameters for low- and medium-profile tiles but is potentially not conservative for asymmetric (s-shaped) high-profile tiles.

}, doi = {https://doi.org/10.1016/j.jweia.2016.05.006}, url = {https://www.sciencedirect.com/science/article/pii/S0167610516302847}, author = {Daniel Smith and Forrest J. Masters and Arindam G. Chowdhury} } @article {bnh-2856, title = {Towards effective mitigation strategies for severe wind events}, journal = {The Australian Journal of Emergency Management}, volume = {31}, year = {2016}, month = {07/2016}, abstract = {

The need to mitigate the losses from severe wind events in Australia has been highlighted repeatedly over the last decade, paralleling that of the hurricane-prone south-east United States of America. The Northern Australia Insurance Premiums Taskforce final report released in 2015, along with numerous other studies and reports, emphasised that mitigation is the only rational solution to reducing loss and improving the current insurance affordability situation. Engineering solutions exist to prevent failures, however post-event observations highlight their lack of implementation. It follows that the current level of community engagement in mitigation activities in cyclone-prone regions of Australia must be improved if losses are to be reduced. This paper discusses issues of engagement and reviews literature and existing mitigation programs as background for a smartphone mitigation tool being developed in Queensland, Australia, and Florida, USA. The Northern Australia Insurance Premiums Taskforce final report can be found at:\ www.treasury.gov.au/ConsultationsandReviews/Reviews/2015/NAIP-Taskforce/Final-Report.\ 

}, url = {https://ajem.infoservices.com.au/items/AJEM-31-03-14}, author = {Daniel Smith and Connor McShane and Anne Swinbourne and David Henderson} } @article {bnh-2356, title = {Improving the resilience of existing housing to severe wind events: Annual project report 2014-2015}, number = {143}, year = {2015}, month = {02/11/2015}, 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} \  Categorize 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 = {143}, author = {Daniel Smith and David Henderson and John Ginger and Martin Wehner} } @article {bnh-2508, title = {Modelling cyclone loss mitigation using claims analysis}, year = {2015}, abstract = {

This paper follows from a series of recent studies conducted by the authors and Suncorp Group Limited which analysed insurance claims from Tropical Cyclone (TC) Yasi (Queensland, 2011) to determine typical drivers of insured loss (i.e. roofing failures, etc.) for residential housing. Using the claims data from TC Yasi, the benefits of mitigation were broadly estimated by reducing claim values based on survey results from builders and assessors on expected loss reduction in properties with mitigation features. This information was provided to Urbis (project consultant to Suncorp) for cost-benefit analysis of the projected benefits of mitigation over the next 50 years in Queensland. In this paper, the claims manipulation approach to modelling loss mitigation is presented and the results for TC Yasi are briefly discussed.

}, author = {Daniel Smith and David Henderson and Lucy M Terza} } @article {bnh-2507, title = {A vulnerability assessment tool for residential structures and extreme wind events}, year = {2015}, abstract = {

Studies of hurricane damage to residential buildings confirm that the risk of wind and/or water damage related losses can be mitigated via retrofit solutions. However, adoption of appropriate retrofits by homeowners has been limited despite its obvious benefits. For several reasons, including high cost of retrofitting, the practical difficulty of implementing upgrades, and other homeowner priorities, the level of structural retrofits remain low. This paper proposes a performance-based design approach to retrofitting, targeted for residential homeowners (and their construction team) to advise on incremental retrofits that ultimately result in desired performance targets for windresistant houses. To specifically engage the homeowner, a user-friendly smartphone application is developed that evaluates the wind resistance and vulnerability of existing homes. The app provides each homeowner an individualized vulnerability assessment, while engaging and educating them on the effects of structural systems and building characteristics on damage and on the options for retrofits and costs associated with the work. The vulnerability assessment is determined using a database of fragility curves, developed originally for the FEMA{\textquoteright}s HAZUS-MH program, and adapted for this use. The analysis yields the top three recommended retrofits for each house as-is, and its expected hurricane-induced economic losses compared against the predicted loss if all the retrofits were conducted. Beta trials of the mobile app will be conducted in at-risk coastal communities in Florida, USA. The authors suggest that direct engagement of homeowners in identifying wind mitigation techniques and solutions may yield more positive outcomes than traditional communication approach and it may eventually increase the number of building retrofits.

}, author = {Daniel Smith and David Roueche and Austin P Thompson and David O Prevatt} } @article {bnh-3458, title = {An historical perspective on the wind resistance of clay and concrete roofing tiles}, journal = {RCI Interface}, volume = {32}, year = {2014}, month = {11/2014}, pages = {22-35}, chapter = {22}, abstract = {

Tiles are one of the oldest forms of roof covering, with usage dating back more than 5,000 years. This article presents an historical overview of roofing tiles in four parts, spanning from early development to the last 40 years of advancements in research and design related to wind load resistance. Code provisions and testing standards are addressed throughout, with emphasis on provisions in the state of Florida. This article also provides a description of ongoing research at the University of Florida to investigate the wind resistance of clay and concrete roofing tile systems.

}, url = {http://rci-online.org/wp-content/uploads/2014-11-smith-masters-gurley.pdf}, author = {Daniel Smith and Forrest J. Masters and Kurtis R. Gurley} }