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Insurance loss drivers and mitigation for Australian housing in severe wind events

Daniel J. Smith1, David J. Henderson1, John D. Ginger1 1Cyclone Testing Station, College of Science, Technology, and Engineering, James Cook University, Townsville, email: [email protected], [email protected], [email protected]

ABSTRACT: Damage investigations conducted by the Cyclone Testing Station (CTS) following severe wind events have typically shown that Australian homes built prior to the mid-1980s do not offer the same level of performance and protection during severe wind events as homes constructed to contemporary building standards. A direct relationship between observed damage modes and societal cost is needed to inform cost-benefit analysis of retrofit mitigation solutions. Policy data from one insurer in the North region of Australia during (2011) were analyzed to identify correlations between claim value, typical damage modes, and construction age. Preliminary results suggest that ancillary damages (i.e. fabric shade coverings, roofing vents, wind-borne debris impacts on wall cladding, etc.) contribute significantly to overall loss for all ages of housing construction. In addition, the frequency of severe structural and water ingress damages is shown to be higher for legacy housing in a region subjected to wind speeds below design level. Structural retrofitting details exist for some forms of legacy housing in Australia but the utility of these details is limited. Hence, the issues of retrofitting legacy Australian housing, including practicality, economy, etc. must also be analyzed. A recently conducted survey of building industry representatives in Australia indicates that the utility of current retrofitting guidelines is inhibited by cost and facultative status. The details of the survey are discussed herein.

KEY WORDS: ICWE14; Resilience; Retrofitting; Legacy housing; Standards Australia; Insurance; Claims Analysis; Structural upgrades; Wind Resistance; Cyclone Yasi.

1 INTRODUCTION 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. 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 analyzed. The primary objective of this research is to develop cost-effective strategies for mitigating damage to housing from severe windstorms across Australia. 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. Tropical resulted in extreme damage to housing in December 1974, especially in the Northern suburbs of Darwin [1]. Changes to design and building standards of houses were implemented during the reconstruction. The Queensland Home Building Code (HBC) was introduced as legislation in 1982 with realization of the need to provide adequate strength in housing. By 1984 it is reasonable to presume that houses in the cyclonic region of Queensland were being fully designed and built to its requirements [2-4]. Damage investigations of housing, conducted by the Cyclone Testing Station (CTS) in Northern Australia from cyclones over the past fifteen years have suggested that the majority of houses designed and constructed to current building regulations have performed well structurally by resisting wind loads and remaining intact [5-12]. However, these reports also detail failures of contemporary construction at wind speeds below design requirements, in particular for water-ingress related issues. The poor performance of these structures resulted from design and construction failings, poor connections (i.e. batten/rafter, rafter/top plate) (Figure 1 and Figure 2), or from degradation of construction elements (i.e., corroded screws, nails and straps, and decayed or insect-attacked timber). Hence, the development of retrofit solutions for structural vulnerabilities are critical to the performance longevity of all ages of housing. Damage surveys invariably reveal some failures due to loss of integrity of building components from aging or durability issues (i.e., corrosion, dry rot, insect attack, etc.). The CTS conducted a detailed inspection of houses built in the 1970s and 1980s in the tropics [13]. Although the majority of surveyed houses appeared in an overall sound condition, the majority had potential issues like decay of timber members, corrosion at a connections, missing/removed structural elements, etc. The damage survey after

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Cyclone Yasi showed substantial corrosion of roof elements in houses less than 10 year old [6]. This study confirmed that retrofitting for improved wind resistance is only part of the process. Ongoing maintenance is also an important part of improving community resilience in severe weather. Considering the prevalence of roofing failures due to inadequate upgrading techniques, current building industry literature for upgrading the wind (and water-ingress) resistance of existing Australian housing were reviewed. In parallel, a brief internet-based questionnaire was distributed to a wide range of Australian building industry constituents in order to identify specific limitations of current upgrading guidelines. The results of the survey are discussed in the current paper. A recently conducted analysis of insurance claims data from Cyclones Yasi (2011) and Larry (2006) in the North Queensland coastal region of Australia is also discussed. The primary objective was to extract insights on typical vulnerabilities in Australia residential housing during cyclonic wind events. Preliminary findings of the analysis are discussed herein, emphasizing comparisons to typical damage modes observed from post-event damage assessments.

Figure 1. Wind-induced failure of a new (< 1 year) metal cladding roof on an old house at the rafter to top-plate connection during (2015) in , Australia.

Figure 2. Wind-induced failure of a metal cladding roof (left) at the batten to rafter connection (right) during Cyclone Marcia (2015) in Yeppoon, Australia.

2 POST-EVENT DAMAGE OBSERVATIONS Following Cyclone Yasi in 2011, Boughton et al [6] showed that homes correctly designed and constructed to the Australian building standards introduced in the 1980s generally performed well under wind load actions. Damage survey results indicated that in the most highly affected areas, ~3% of post-1980s homes experienced significant roof damage, in contrast to ~15% for pre- 1980s homes. Greater than 20% of the pre-1980s housing experienced significant roof loss in some areas. The relatively low incidence of roofing damage to post-1980s buildings indicates that modern building practices are able to deliver higher performance for the roofing structure in severe wind event conditions. A damage survey following [7] showed that although wind-induced structural damage was minimal for 95% of contemporary housing, many contemporary houses experienced water ingress damage from wind-driven rain. A survey conducted by Melita [10], details building envelope failures during Cyclone Larry. Approximately 75% of post-1985 homes experienced

14th International Conference on Wind Engineering – Porto Alegre, Brazil – June 21-26, 2015 3 water ingress through breaches in the building envelope (i.e. broken windows, punctured cladding, failed fascia or guttering, etc.). In many cases replacement of internal building components and owner contents were required. These observations are similar to those of other other post-event damage assessments in Australia (e.g. [11], [12], [8], and [5]). Consistent findings include: • In general, contemporary construction performance for single family residential housing was adequate under wind loading • Significant structural damage to legacy housing was typically associated with loss of roof cladding and/or roof structure. There were many examples of legacy housing with relatively new roof cladding installed to contemporary standards (i.e. screwed fixing as opposed to nailed) but lacking upgrades to batten/rafter or rafter/top-plate connections, resulting in loss of roof cladding with battens attached • Corrosion or degradation of connections and framing elements initiated failures • Where wind-induced structural failures were observed for contemporary housing, they were often associated with either poor construction practice or the application of an incorrect site design wind speed • Breaches in the building envelope (i.e. failed doors and windows, debris impact, etc.) exacerbated failure potential from increased internal pressures • Extensive water ingress damages were observed for structures with and without indication of exterior building damage These observations suggest the majority of contemporary houses remained structurally sound, protecting occupants and therefore meeting the life safety objective of Australia’s National Construction Code (NCC). However, contemporary homes did experience water ingress (resulting in loss of amenity) and component failures (i.e. doors, soffits, guttering, etc.) with the potential for damage progression to other buildings, thus failing to meet specific objectives and performance requirements of the NCC.

3 INSURANCE CLAIMS ANALYSIS A direct relationship between observed damage modes and societal cost is needed to inform cost-benefit analysis of retrofit mitigation solutions. Policy data from one insurer in the North Queensland region of Australia during Cyclone Yasi (2011) were analyzed to identify correlations between claim value, typical damage modes, and construction age. This was achieved by extracting qualitative and quantitative insights from aggregated insurance policy data from one insurer at the time of the event. The aggregated data included information on policies both with and without a claim for Cyclone Yasi. A more detailed analysis that addresses topographic effects, etc. on the wind field at policy level will be completed as a next step (current results are preliminary). Loss Ratios The claims data was subdivided by loss ratio (i.e. claim value / insured value) into five bins (Table 1). Bins were specified based on a general range of damage modes observed for a corresponding range of loss ratios. These relationships were determined by a review of 180 assessor’s reports for claims of varying loss ratio. The loss ratio bins are used broadly to discuss correlation between damage severity and construction age of housing in the Townsville region.

Table 1. Loss ratio bins for Cyclone Yasi insurance claims analysis (one insurer) with typical damage modes extracted from assessor’s reports (note: typical damages for higher loss ratio bins also include all damages from lower ratio bins). Loss Ratio Bin Description Typical Damage 0 No claim filed N/A Minor roofing issues and water ingress, minor 0 – 0.09 Minor damage debris impact damage, fencing, fabric shade coverings, roofing vents, etc. Moderate roofing and water ingress, ceiling 0.1 – 0.49 Moderate damage damage, broken fenestration, exterior cladding, etc. Severe roofing failures, extensive water ingress 0.5 – 0.99 Severe damage damages, interior components damage and broken fenestration, etc. Severe roofing failures, extensive water ingress Severe damage > 1.0 damages, interior components damage and broken /underinsured fenestration, etc.

The “No claim filed” bin refers to the number of policies that did not file a claim following Cyclone Yasi and hence are assumed to have avoided damage. The “Minor damage” bin refers to claims with small loss ratio (< 10%), which was generally associated with ancillary damages (i.e. fabric shade coverings, fencing, roof vents, etc.) and minor water ingress damages. The “Moderate damage” bin refers to claims with moderate damages typically to roof cladding, the building interior, etc. due to wind load and water ingress. The “Severe damage” bin refers to claims with relatively large loss ratios associated with damages typically including severe roofing failures, large-scale water ingress damage to building interior, etc. The “Severe damage/underinsured” bin refers to claims with loss ratios greater than one (i.e. claim exceeds policy limit). This bin was created to characterize the number proportion of housing that suffered complete failure. Damages observed for claims in this bin were typically extreme

14th International Conference on Wind Engineering – Porto Alegre, Brazil – June 21-26, 2015 4 cases of the damage modes described for the “Severe damage” bin. Figure 3 shows the spatial distribution of properties falling within the four non-zero loss ratio bins for the North Queensland coastal region and the estimated wind field near the point of landfall for Cyclone Yasi.

Figure 3. North Queensland coastal region impacted by Cyclone Yasi (2011) with distribution of claims subdivided by four loss ratio bins (claim value/insured value) and wind field estimation [6]. Loss ratios increase directly with wind speed. The frequency of large loss ratios (i.e. large claims) was greatest, in geographic locations nearest the point of landfall (i.e. Cardwell, Mission Beach, etc.) where wind speed estimates were 210-240 km/h [6]. However, claim frequency was significant for the entire North Queensland region, even in areas of relatively low wind speed estimates (i.e. ~135 km/h in Townsville, ~90 km/h in ). A total of 26% (14,282) of policies in the area affected by Cyclone Yasi (North Queensland coastal region) filed a claim. Approximately 86% (12,296) of those claims were within the “Minor damage” loss ratio bin. Claims in this loss ratio bin represent 29% of the total claims payout cost accrued by one insurer for Cyclone Yasi in the North Queensland coastal region. Approximately 12% (1,665) of claims in the North Queensland coastal region were the “Moderate damage” loss ratio bin, contributing 44% to the total payout cost for one insurer. The majority of claims this size were filed in the areas subjected the highest wind speeds (Figure 3). Severe damage claims (including underinsured bin) represented at total of 27% of the total claim-related losses for one insurer in the North Queensland coastal region. Typical damage modes for claims of this size generally more extreme versions of those described for the “Moderate damage” bin (i.e. severe roofing failures, interior damage from water ingress, fenestration damage, etc.). The contributions to overall cost from moderate to severe claims typically associated with roofing and building envelope failures, indicate that a mitigation program emphasizing structural roofing and opening protection upgrades may significantly reduce the frequency of relatively large claims and thus decrease societal cost. Townsville Analysis Region To isolate a relatively high population of housing subjected to a similar range of wind field characteristics (i.e. velocity, direction, and duration) and rain fall intensity, preliminary analysis emphasized the Townsville region. Peak 3-second gust wind speed measured at the Townsville airport weather station (10 m) was 135 km/h during Cyclone Yasi. Figure 4 shows the spatial distribution of construction ages for policies in the city centre of the Townsville region. For clarity, the greater Townsville area of modern housing suburbs to the North, West, and South are omitted. A total of 23,878 policies from the North Queensland coastal region were included in the Townsville region, 30% of which filed a claim associated with Cyclone Yasi.

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Figure 4. Spatial distribution of residential property construction age in the city centre area of the Townsville region for policy holders from one insurer during Cyclone Yasi (2011) . The inland moving housing development of the central Townsville area over time is clearly shown. In general, for the main part of the city, the housing stock near the coastline is of an older construction age. This is an important consideration for risk modelling. Wind conditions near the coast will generally be more severe than inland areas during cyclonic events. Figure 5 shows the loss ratio for claims across the central Townsville area. Considering wind speeds during Cyclone Yasi were just above 50% design level for the region, there was a high amount of claims distributed throughout the city and across all age groups. “Minor damage” claims were dominant and occurred uniformly throughout the region. Their occurrence appears to be independent of housing age and proximity to the coast. However, moderate and severe loss ratio claims are more prevalent in areas near the coastline where older housing is also more prevalent.

Figure 5. Spatial distribution of claims subdivided by four loss ratio bins (claim value/insured value) in the city centre area of the Townsville region for policy holders from one insurer during Cyclone Yasi (2011).

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Table 2 shows the relative contributions of claims in each loss ratio bin as a proportion of the total number of claims filed in the Townsville region. As suggested by Figure 5, the majority of claims (~94%) were within the “Minor damage” loss ratio bin (0- 0.09). The sum of claim values from Cyclone Yasi for the Townsville region was $AUD 63.5 million (one insurer). Minor claims (e.g., fencing, fabric shade coverings, garage doors, minor impact damages to wall cladding, etc.) comprised 60% of the total claims cost of for the Townsville Region. For “Moderate damages” (0.1-0.49) in the Townsville Region, 390 claims were filed (i.e. 5% of the Townsville regions claims contributed 32% of the total claims cost). These claims were generally associated with moderate damage to the roofing structure, water ingress damages to the building interior, etc. and occurred in an area where wind speed estimates were significantly less than design level (240 km/h). This supports the need for improved building standards for both upgrading of older housing and maintenance and certification for newer construction. Table 2. Frequency and cost statistics for the four non-zero damage levels and claims from one insurer in the Townsville Region during Cyclone Yasi (2011). Loss Ratio % Total Claim Cost # Claims % Claims 0-0.09 60% 6851 94% 0.1-.49 32% 390 5% 0.5-.99 6% 27 <0.5% >= 1.0 2% 5 <0.1% Total 100% 7273 100%

Figure 6 shows the relationship between claim ratio and age of construction for homes in the Townsville Region. Each percentage represents the proportion of claims in that loss ratio bin relative to the total number of claims for the age grouping. The five construction time periods were selected based on the progression of typical housing material and construction characteristics in Queensland [14]. 100% 1.8% 3.5% 2.3% 1.8% 1.0%

27.1% 25.6% 30.1% 32.8% 37.5%

50%

70.8% 73.4% 66.0% 64.8% 60.7%

0% <1925 1925 - 1959 1960 - 1975 1976-1981 1982 - 2011

RIF - 0 CLAIM - 0 - 0.09 CLAIM - 0.1 -0.49 CLAIM - 0.5-0.99 CLAIM - >= 1.0

Figure 6. Building age vs loss ratio bin (see legend) contributions to the total number of claims filed in relation to Cyclone Yasi for the Townsville region (note: “CLAIM 0.5-0.99” and “CLAIM >1.0” bin proportions are <1% and therefore labels are omitted from this figure for clarity). The loss ratio trends for the Townsville region are similar to those for the North Queensland coastal region. This is due in large part to the relatively high population in Townsville, which is included in the North Queensland coastal region. Preliminary findings include: 1. Post-1980s housing had a lower frequency of claims (all sizes) and a lower proportion of moderate/severe claims than pre- 1980s housing

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2. However, the proportion of moderate damage claims for post-1980s housing (25.6%) is significant in comparison to older housing (27-37%) considering the design level (240 km/h) of contemporary construction in relation to Cyclone Yasi wind speed estimates for the Townsville region. As evidenced by post-event damage observations (Section 2), the majority of contemporary houses remained structurally sound, protecting occupants and therefore meeting the life safety objective of Australia’s National Construction Code (NCC). However, contemporary homes did experience significant water ingress (resulting in loss of amenity) and component failures (i.e. doors, soffits, guttering, etc.) with the potential for damage progression to other buildings, thus failing to meet specific objectives and performance requirements of the NCC 3. Housing constructed between 1925 and 1981 in the Townsville region did not perform as well as housing constructed either before or after this time period. Post-event damage observations in the area support this trend. Materials in pre-1925 houses may be less prone to water damages due to construction materials of the time period (e.g., water recedes through timber floors, asbestos/timber ceilings are water-resistant, etc.). Many of these older homes are also more likely to be upgraded structurally or renovated because of increased market value, historic value, etc. Figure 7 provides an example of roofing loss observed for a home constructed in the 1960s in Townsville after Cyclone Yasi. 4. The proportion of policy holders that did not file a claim (“RIF-0” e.g., 70.8%, 66.0%, 64.8%, etc.) were lower for the Townsville region than for the North Queensland coastal region (data not shown) for all ages of housing (i.e. likelihood that a claim was filed in the Townsville region was higher than for the entire Cyclone Yasi affected area, despite the relatively low wind speeds that were generated in the area.

Figure 7. Loss of roofing in 1960s housing in Townsville, Australia following Cyclone Yasi (2011).

4 CURRENT PROVISIONS FOR UPGRADING There are existing guidelines for upgrading of older houses in the form of handbooks (HB132) published by Standards Australia in 1999 [15-16]. However, the success of these handbooks has not been effective in light of recurring severe wind damage to older structures. These details and methods were reviewed to consider reasons for lack of use. To further investigate, an online survey was distributed nationally to members of Building Codes Queensland (BCQ), Housing Industry Association (HIA), Master Builders Association (MBA), Australian Institute of Building Surveyors (AIBS), BNHCRC, and AFAC. Objectives of the survey were to estimate the extent of HB132 usage and determine what other references/practices (if any) are used in retrofit construction. From research and informal interviews with builders, regulators, and homeowners it was apparent that common themes of limited knowledge of and access to appropriate retrofitting literature may be a factor. This information helped inform the basis of the survey which was 12 questions and included both short answer and multiple choice responses. The breakdown of question topics was as follows: a) participant occupation/location (3 questions), b) typical retrofit practices and literature (3 questions), c) format preference for literature (1 question), and d) knowledge of upgrading literature (4 questions). The survey was distributed via email or social media to the members of each participating organization. A total of 245 survey responses were collected. Participants were not required to answer all questions. The occupations of 221 participants were predominantly certifiers (65%), regulators (24%), and builders (10%). Other occupations included engineers (5%), architects (3%), homeowners (3%), and roofers (<1%). Additional responses (36 total) were collected via an “other occupation” comment box that included building inspectors, designers, and surveyors. The state/territory in which participants performed their occupation was recorded for 244 participants. The majority of responses were from Queensland (38%) and New South Wales (20%). A significant number of responses were also recorded for (14%), (11%), and (10%). Responses from , Australian Capital Territory, and totaled approximately 3% each.

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Participants were asked to provide their formatting preference for occupational reference literature. Over 62% of participants prefer access to both hardcopy and electronic versions of reference materials, 28% prefer electronic only, and 10% prefer hardcopy only. Based on these results, an effective guide for construction retrofit techniques should be developed with strong consideration of both electronic and hardcopy distribution. AS 1684 Residential Timber Framed Construction is a four-part Australian Standard covering design criteria, building practices, tie-downs, bracing and span tables for timber framing members. It is the primary reference publication for housing throughout Australia during new construction projects. Although the standard does not address retrofit construction practices, the survey results indicate it use for reference during structural upgrading of existing timber framed residential structures. In order to determine the extent to which this occurs, participants were asked if AS 1684 is referenced during alteration or reroofs to timber framed structures. Of the 240 responses recorded for this question, over 84% claimed to use AS 1684 (Figure 8). In contrast, when participants were asked whether or not they were familiar with HB132, 91% responded they were not. Therefore, nearly all of the Australian residential construction industry is utilizing a reference document that is not designed for retrofitting and furthermore are unaware that a document for retrofitting does exist.

84% Yes No 91%

16% 9%

AS 1684 HB 132

Figure 8. Proportions of building industry personnel that reference (“Yes”) or do not reference (“No”) AS 1684 Residential Timber Framed Construction (Australian Standard for new construction) and HB 132 Structural Upgrading of Older Houses (non-mandatory reference guidelines for upgrading existing structures). If participants indicated they were familiar with HB132, they were asked to comment on utility of the document. Of the 22 responding participants, 27% found HB132 “very useful”, 36% found it “somewhat useful but could be improved”, and 36% found it “not useful at all”. When asked why they found HB132 useful or not, typical responses included “details are not architecturally acceptable to clients” and “the cost of each part of HB132 is $70, as it is only an advisory document, this is a disincentive for its use”. Participants were asked to identify what improvements could be made to HB132. A total of 19 responses were recorded. Most indicated that the cost of access to HB132 is too expensive. Furthermore, because HB132 is a handbook as opposed to a statutory document, there is reduced motivation for purchasing it. One response suggested moving the retrofit details “into AS1684 so more people know about them”. The survey results suggest that in order to enhance reference literature for structural upgrading of existing Australian housing, future development of retrofitting guidelines must consider cost, enforcement, literature format, and architectural acceptability of structural details.

5 CONCLUSIONS The preliminary analysis of insurance data indicate that roofing, water ingress, and fenestration damages are the most dominant drivers of loss during cyclones and can occur in housing of all ages. These findings are supported by observations from post-event damage assessments. The data indicate that housing constructed between 1925 and 1981 is at a relatively higher risk of structural damage, in particular to roofing systems. However, a significant proportion of contemporary housing also experienced loss of amenity via structural and water ingress damages, indicating that modern housing did not perform as expected per the National Construction Code (NCC) in some cases. Poor construction practice and the application of incorrect site design wind speed are also known to occur in contemporary construction. The HB132 survey data provides valuable insight into factors limiting the success of retrofitting literature. Results indicate that utility of current retrofitting guidelines is inhibited by cost and non-mandatory status, both of which should be considered the development of a comprehensive mitigation program. A targeted mitigation program that reduces vulnerability to structural and water ingress damage modes, can reduce insured losses in Australian housing of all ages. Such programs should emphasize the importance of implementing a home maintenance routine in the long-term (e.g., repairing corroded metal supports, monitoring roof cladding tie-downs and water-tightness, replacing degraded timber, etc.) and cyclone preparation in the short-term (e.g., removing shade coverings, pruning trees, removing debris and unsecured items from the yard, etc.).

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ACKNOWLEDGMENTS The authors would like to thank Suncorp Group Limited and the Bushfire and Natural Hazards Cooperative Research Centre. Additional thanks to Master Builders Association (MBA), Building Codes Queensland (BCQ), Housing Industry Association (HIA), Australian Institute of Building Surveyors (AIBS), and the Australasian Fire and Emergency Service Authorities Council (AFAC) for project support and assistance in distributing the online survey.

REFERENCES [1] Walker, G. (1975). Report on Cyclone Tracy – Effect on buildings – Dec 1974. Australian Dept of Housing and Construction. [2] Standards Australia (2011), AS/NZS 1170.2:2011 Structural design actions Part 2: Wind actions, Standards Australia, Sydney NSW, Australia. [3] Standards Australia (2011), AS 4055 Wind Loads for Housing, Standards Australia, Sydney, NSW. [4] Standards Australia (2010), AS 1684.3:2010 Residential timber-framed construction – Cyclonic areas, Standards Australia, Sydney, NSW, Australia. [5] Boughton, G. & Falck, D. (2007) George: Damage to buildings in the Port Hedland area. Cyclone Testing Station. Townsville, James Cook University. [6] Boughton G., Henderson D., Ginger J., Holmes J., Walker G., Leitch C., Somerville L., Frye U., Jayasinghe N. and Kim P., (2011) Tropical Cyclone Yasi: Structural damage to buildings, Cyclone Testing Station, James Cook University, Report TR57. http://www.jcu.edu.au/cts/research_reports/index.htm [7] Henderson, D., Ginger, J., Leitch, C., Boughton, G. and Falck, D. (2006) Tropical Cyclone Larry – Damage to buildings in the Innisfail area. Cyclone Testing Station. Townsville, James Cook University. [8] Henderson, D. & Leitch, C. (2005) Damage investigation of buildings at Minjilang, Cape Don and Smith Point in NT following Cyclone Ingrid. Cyclone Testing Station, Townsville, James Cook University. [9] Henderson, D.J., Leitch, C., Frye, U., Ginger, J.D., Kim, P., Jayasinghe, N.C., (2010). Investigation of Housing and Sheds in Procerpine, Midge point, and Airlie Beach, Following Tropical Cyclone Ului. Cyclone Testing Station, James Cook University, Townsville.TR 56. [10] Melita, B. (2007) Performance of Housing Envelope in Tropical Cyclone Larry. School of Engineering. Townsville, James Cook University. [11] Reardon, G., Walker, G. & Jancauskas, E. D. (1986) Effects of Cyclone Winifred on Buildings. CTS. Townsville, James Cook University. [12] Reardon, G., Henderson, D., Ginger, J., (1999). A structural assessment of the effects of Cyclone Vance on houses in Exmouth WA Cyclone Testing Station. 1999, James Cook University, Townsville.TR48. [13] Henderson, D. & Somerville, L. (2012) TIO Housing survey (Built 1975 to 1980). TS859, Cyclone Testing Station, Townsville, James Cook University. [14] Henderson, D. and Harper, B. (2003). Climate Change and Tropical Cyclone Impact on Coastal Communities’ Vulnerability. CTS Report TS582 for Dept Emergency Services and Dept Natural Resources and Mines, Queensland Government. http://www.longpaddock.qld.gov.au/about/publications/vulnerabilitytocyclones/stage4.html [15] Standards Australia (1999). HB 132.1:1999 Structural upgrading of older houses, Part 1: Non-cyclonic areas, Standards Australia, Sydney, NSW [16] Standards Australia (1999) HB 132.2:1999 Structural upgrading of older houses - Part 2: Cyclone areas, Standards Australia, Sydney, NSW

14th International Conference on Wind Engineering – Porto Alegre, Brazil – June 21-26, 2015