EA / ATSE joint seminar Engineering for Extreme Natural Events

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Engineers Australia

ATSE Joint Seminar

Earth, Wind, Fire, Water: Engineering for Extreme Natural Events

Thursday 15th September 2011

Western Australia Division

Engineers Australia WA Division

Earth, Wind, Fire, Water: Engineering for Extreme Natural Events 15 Sept 2011

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Earth, Wind, Fire, Water: Engineering for Extreme Natural Events

Abstract

This article describes the purpose, format, content, and recommendations arising from a half-day seminar held to consider the nature, role and future challenges of Engineering for extreme natural events. In particular the seminar concentrated on Engineering related to the four areas of earthquake (earth), high-speed winds (wind), bushfires (fire) and large-amplitude water waves (water). Bringing experts in the different areas together proved to be invaluable, no more so than in the concluding panel session. The interaction with the audience also highlighted areas of concern that had not previously been discussed. Several themes emerged that were general across the four different event areas, most especially the notion of risk and its meaning for different groups from Engineers through to the general public. This leads to the question of whether properties and infrastructure more subject to inundation, fire, seismicity or soil liquefaction have a higher cost for insurance, not be insurable or in some cases be declared unable to be sold. For such deliberations, it was agreed that an increased understanding and level of communication across the many different stakeholders is highly desirable.

1. Introduction

2011 has brought into sharp focus the forms and effects of extreme natural events. Earthquakes in Christchurch and Japan, tropical cyclones in Queensland Australia and the U.S Eastern Seaboard along with a virulent tornado season in the U.S, bushfires both nationally and around Perth, Western Australia, the Japanese tsunami in Sendai province and flooding in Brisbane, Queensland have caused significant fatalities and wrought much damage. The occurrence of extreme natural events seems to be increasing and climate change may be implicated. It is therefore timely that the role of Engineering in safeguarding life and property against the effects of extreme natural events should be considered and assessed.

Engineers Australia (EA) and the Australian Academy of Technological Sciences and Engineering (ATSE) combined to host a half-day seminar Earth Wind Fire Water – Engineering for Extreme Events held at Curtin University, Perth on the15th September 2011. This seminar linked to, and developed from, the seminar City to Cape – 2100 sea-level rise mounted by ATSE, EA and Curtin University on the 22nd July 2010 and its arising published report [1].

The theme of the seminar reported upon herein was the contributions of Engineering to controlling the adverse effects arising from extreme natural events: earthquake, storm, bushfire and inundation. In tandem, the seminar served to raise awareness of humanitarian engineering, EA‟s 2011 focus, as an crucial arm of Engineering through the preservation of life and property in the face of, and after, devastating natural events. The seminar also sought to communicate the special challenges associated with designing and preparing for extreme natural events. The seminar comprised four main presentations, each focusing on one of the extreme-event sub-themes under the shorthand titles, earth, wind, fire and water. These are reported upon in Section 2. Speakers were asked to establish the nature of the problem; highlight challenges for engineers, scientists, disaster managers and planners; suggest what could be done better; and to include reference to social or management challenges and the special plight of developing communities in such circumstances. While it was not expected that each of the four speakers could address all of these aspects, they were addressed in one form or another through the seminar presentations taken in their totality. The presentations were followed by a panel discussion that drew out common threads, identifying challenges and matters of concern, that apply broadly to Engineering and its role, responsibilities and contributions across all extreme natural events. This discussion and the recommendations that emerged from it are summarised in Section 3. In addition to EA and



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ATSE membership, the target audience of the seminar included people with a professional interest in the impact of the topic and the capacity to act on the subjects of the presentations including State government, local government, planners, academics, business and industry as well as the members of the general public.

The overall message that emerges is clear in that engineering education and practice needs to accommodate the prospects of a greater frequency and greater severity of natural disasters. Decision-makers, planners, engineers and architects need to work together to increase the rate of structural survival following earthquakes, cyclones, bushfires, deluges and coastal inundation. Regulators and the insurance industry need to consider limiting risk, recognising the compounding of hazard and frequency, and all parties need to re-embrace the Precautionary Principle, based upon sound data and well-established knowledge.

2. Findings Reported

What follows is a summary of key points that emerged from each of the four presentations. Note that the titles and abstracts of the presentation and speaker biographies are presented as Appendix 1, while the slides for each of the presentations and the iLecture (speaker audio synchronised with slides) of the entire seminar are available at [2].

2.1 Earth – Presenter: Dr David Brunsdon

This presentation highlighted the risks of failure, the need for risk management and the role of engineers. „Risk‟ is a function of both likelihood and potential damage. Its management can be summarised by the 4Rs of risk: reduction, readiness, response, recovery. Accounting for risk in design covers the spectrum: avoid, transfer, control, accept. The focus for Engineering is usually upon „control‟ whereas effective risk-management includes all four parts of the spectrum. Accordingly, Engineers need to increase their involvement more widely, especially in communicating and sharing their expertise with other professionals such as planners and architects.

Risk-reduction strategies for infrastructure development should be applied at each of three stages, these being (i) „Site yet to be developed‟ (site selection and planning with regard to potential hazards such as liquefaction and fall or collapse of geologic material), (ii) „[Site] Developed, but not built (applying necessary design considerations and building regulations), and (iii) „Built, existing infrastructure‟ (reviewing against standards). It was noted that the appropriate implementation of these strategies is being affected by sea-level rise for coastal developments.

The community tends to focus on the consequences of failure, whereas engineers tend to focus on the likelihood (e.g. the 100 year earthquake). These two outlooks need to be combined. For example, a rating of „low seismicity‟ indicates that the average time between events is large but it does not mean that all events are small.

The presentation highlighted some of the dilemmas of design for earthquakes. Buildings may need to have good escape systems, but the best way to survive an earthquake is by remaining within a resilient building during the shaking event, as falling masonry often renders the surroundings of the building unsafe. The escape system is needed to exit the damaged building after the event.

Building design needs to take into account post-disaster use; design for damage tolerance or design for damage resistance. For example, hospitals, assembly halls and emergency services buildings need to remain in operation after the event.



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Finally, the presentation addressed the role of Engineering in the aftermath of a severe earthquake, in the first instance triaging buildings in the affected area to aid search and rescue operations, assessing the safety of entry to „pancaked‟ buildings and, later, leading engineering work to permit entry to collapsed buildings in the search for survivors.

2.2 Wind – Presenter: Mr Charles Boyle

This presentation focused on the need to blend traditional and modern western knowledge to find building solutions for developing countries, using the Solomon Islands as an example. There is a tendency in the Solomon Islands to view European housing as „better‟ as a result of aspirations being set by former colonial administrations or present „Western‟ influences. However, such housing is costly, complex in construction and maintenance, and can be culturally intrusive. Instead, the appropriate use of local materials and techniques combined with western structural-engineering knowledge can produce greatly improved and culturally appropriate outcomes with buildings that are cyclone resistant.

Thus, for example, the lack of continuity between the floor, walls and roof of traditional buildings leads to complete loss of the building in high winds. A blended design that utilises corrugated steel roofing tied through the walls to the ground produces a far more resilient building, yet does not alter the traditional floor plan and can make use of many of the local materials (e.g. bamboo).

The presentation cautioned against „transitional‟ buildings that comprise an ad-hoc, or ill-considered, combination of local and western materials and designs. Correct hybrid building approaches need to be carefully engineered to yield techniques and material use that realise complementary benefits of the traditional and the modern. Hybrid technology requires a systematic approach that includes the documentation of traditional learning and skills, established wisdoms and local materials that will be trialled or adapted to work effectively with modern materials and techniques. In the subsequent design phase of hybrid buildings, prototyping trials (at all scales, from fixing techniques through to entire building) are essential. The roles of the administrating organisation, most effectively undertaken by NGOs, was emphasised to ensure continuity of process, dissemination and adoption of new hybrid techniques.

2.3 Fire – Presenter: Mr Ralph Smith

This presentation communicated the lessons learned from the Roleystone and Toodyay fires of recent years in Western Australia. However, many of the causes of and means to reduce damage are broadly applicable to other regions and situations. In particular, a range of data was presented that demonstrated two main points:

Reducing the fuel loads surrounding buildings, both the Building Protection Zone (BPZ) and Hazard Protection Zone (HPZ), by proper property management reduces the energy release rate to a point where the fire can be controlled using water. If this is not done, then the fire cannot be extinguished.

Regardless of the main building cladding materials (e.g. brick, iron), buildings are not fire resistant if there are any entry points for embers. The vast majority of houses lost in the fires studied were the result of ember attack some distance away from the main fire. Typical ember entry arises from rooftop evaporative air-conditioners, lack of boxed eaves and, often, a lack of common sense in the identification of vulnerabilities.

The risk of fire damage can be significantly reduced by following existing well-developed standards and easy-to-understand guidelines for property owners. A major challenge lies in



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persuading planners to adopt, councils to enforce and the public take the actions that can dramatically mitigate the effects of bush/forest fires.

2.4 Water – Presenter: Prof Chari Pattiaratchi

This presentation highlighted the destructive nature of a tsunami and the complicated nature of the phenomenon. Earthquake-induced waves are refracted and reflected by subsea topography and coastlines, leading to enormous variations in the strength of the waves as they strike different parts of the coast. Reflected waves may in fact lead to larger tsunamis that reach a coast many hours after the original incident waves. Understanding the topography of the extended region is therefore a key to identifying potential tsunami events.

Meteorological tsunamis can also be induced by storms moving across the surface of the ocean and these can be as important, through their frequency, as the more dramatic geologic tsunamis. Thus, along the coast of Western Australia a meteorological tsunami that generates a wave-height of one metre is very significant when it impacts the southern part of the state for which the tidal range is approximately only 0.5 metres. Clearly, the frequency of such tsunamis increases with the increased frequency of storm events associated with climate change.

The presentation described the advanced tsunami prediction models that are currently available to assist in early warning and prediction of the level of likely inundation resulting from tsunamis produced by both geological and storm events. Even with a predictive capability, implementing coastal and beach responses remains complex with appropriate actions depending upon a combination of factors that may be local to each particular region impacted by the tsunami.

Modelling and data-analysis also evidences the impact of sea-level rise on increasing the strength and frequency of tsunamis, noting that the current 100 year flooding event may be expected to occur on a monthly basis by 2050 if sea levels continue to rise at the rate they have been doing so over the last 100 years. Accordingly more effective communication to and understanding by planners and decision-makers for coastal regions is essential.

3. Discussion and recommendations

Several points were made during the discussions, with a focus on changes needed to the education of scientists and engineers, and of governments and regulators and the general public that utilise their services. Overall the key elements and recommendations are as follows.

There is no escape from natural disaster. From city centres to rural communities, from the coast to the mountains, there is the potential for natural disasters in one or more forms, be they inundation, earthquake, fire or storm. The effects of global warming are increasing the likelihood of extreme events related to all but earthquake. The magnitude and frequency of global natural disasters appears to be increasing and whatever the cause we need to engineer to reduce the impact of compounded effects.

The problems of designing and preparing for natural disasters cannot be completely solved using existing knowledge. This is true for developed and particularly true in regard to developing nations, where cultural factors and resource limitations may render modern „developed‟ technologies and practices inappropriate. Innovative thinking is needed, and a willingness to understand local techniques and materials, in order to blend effectively traditional and western knowledge. In developed countries, similar considerations may also apply. Throughout, however, the continuing policies of developers and regulators to encourage building of infrastructure close to the water table or a flood plain possibility must be reined in.



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Service to the community is to be encouraged. Apart from the obvious community and humanitarian outcomes, this is an ideal way for engineers, technologists and managers to understand the competing demands and influences that must be addressed in any truly effective solution.

Engineers and Scientists are not very well prepared for working with uncertainty. Clients are nearly always looking for the cheapest solution, but decreasing the risk of damage from natural disasters usually increases the costs. Such factors are often not taken into account as a result. Professionals should be more willing to lay out the risks and consequences, and to offer a range of solutions that mitigate risks at different levels.

Engineers need to understand and manage the balance between risk and consequence in their design work and decisions, and to broaden their involvement to all stages in the development of infrastructure. Current obstacles that need to be overcome include: Engineers usually communicate through indirect channels that may be insufficiently forceful; it is difficult for Society to understand „risk‟ as a parameter worked with by Engineers; media reporting and language can be misleading - for example, it is preferable to use „intensity‟ instead of „magnitude‟ in earthquake descriptions.

Government and insurance industry decisions can have a large impact on disaster mitigation, either by taking firm action to prevent development in areas prone to disaster (e.g. flood plains) or to make prohibitive the cost of insuring in risky situations.

4. Concluding Remarks The design of the seminar proved to be very effective for the delivery of its expected outcomes. Combining sometimes disparate disciplines that separately address Engineering for extreme natural events, and bringing together experts in these areas, served to identify factors, shortcomings and recommendations that cut across the different disciplines and which can perhaps be better tackled at an all-of-Engineering level. Overall, the seminar concluded that extreme natural events are becoming more frequent and that this warrants an increased focus on the concomitant engineering challenges both within developed and developing communities in order to find solutions that are technically effective while also being socially and commercially appropriate.

Acknowledgement

The authors and organisers of the seminar are grateful for the support of Curtin University for providing the seminar venue and administrative support through Ms Sucy Leong.

References

[1] R.J. Purdy, A.D. Lucey and R.E. Smith 2010. City to Cape: 2100 Sea-level Rise, Seminar Report, Pub.: The Australian Academy of Technological Sciences and Engineering, ISBN 978 1 921388 17 0. (Also available as a .pdf document at www.atse.org.au)

[2] D. Brunsdon, C. Boyle, R. Smith and C. Pattiaratchi, 2011. Presentation slides and iLecture for Earth, Wind, Fire Water: Engineering for Extreme Natural Events seminar. At: www.engineersaustralia.wa.events and www.atse.org.au

http://www.atse.org.au/

http://www.engineersaustralia.wa.events/

http://www.atse.org.au/



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Appendix 1:

Titles and abstracts of speaker presentations and author biographies

EARTH

Planning and Design for Earthquakes: Consequences and Opportunities

Mr Dave Brunsdon New Zealand Society for Earthquake Engineering

Engineers have a key role in reducing the risk to the community from extreme natural hazard events. While it is implicit in much of what professional engineers do on a day to day basis as they apply design codes, the wider context of this risk mitigation work is not always fully appreciated, particularly for complex hazards such as earthquake. The effective mitigation of urban earthquake risk involves consideration of the following elements:

Understanding of the components of seismic hazard, and in particular the threat of permanent ground deformation;

Conveying seismic risk to urban planners (what the consequences are of developing on at-risk land);

Ensuring that building codes provide for an appropriate level of seismic resistance, and function within an effective regulatory framework;

Having appropriate arrangements (both technical and regulatory) in place for assessing and strengthening potential at-risk older building stock;

Ensuring that both the construction and renewal of infrastructure assets includes seismic resilience considerations

A key enabler that sits across these elements is establishing and conveying the consequences of seismic hazards on the built environment. Professional engineers are uniquely placed to undertake this role, and indeed have the responsibility to do so. In the current climate of strong awareness of natural hazard threats, this represents a significant opportunity to make a difference. This presentation will cover each of these earthquake risk mitigation aspects, drawing upon the September 2009 Padang earthquake and the Canterbury earthquake series of 2010/11 as case study examples.

Biography Dave is a Fellow and Past-President of the New Zealand Society for Earthquake Engineering, and is a member of the Australian Earthquake Engineering Society and the Institution of Engineers Australia. He is a director of Kestrel Group Ltd, a New Zealand-based consulting practice specialising in strategic emergency management planning for local and central government agencies and infrastructure providers. In 2009, Dave led a team of NZ engineers to assist government agencies following the devastating Padang earthquake in Indonesia. In September last year he co-ordinated the building safety evaluation process immediately following the Darfield, Canterbury earthquake, and in February he led the NZ USAR Engineering team during the response to the Christchurch aftershock. He continues to be closely involved in activities relating to the building recovery process there.

WIND

Advancing Cyclone Resistant Construction Practices with Local Communities in the Solomon Islands Mr Charles Boyle Architect/Project Manager, Curtin University

While engineered timber frame construction can be formally designed quantified and quality controlled, traditional building practices are too varied in both the level of skill and quality of materials to be similarly



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assessed. Being as much an issue of social dynamics, anthropology and material culture, the latter falls as much within the domain of the architect as that of the structural engineer. While a high population growth, urban growth, land ownership and general development aspirations have seen Solomon Islanders aspire to better housing, the economic conditions of a country still recovering from what was in effect a civil war constrain affordability and educational opportunity. In the informal housing sector this typically sees traditional materials used to emulate modern timber framed building construction, or the use of modern building materials to traditional construction methods, an approach favoured for re-construction by the government following 1985 cyclone Namu and which stimulated Charles‟ interest in disaster mitigation through better building practice and his work with the Australian Overseas Disaster Response Organisation, Ausaid and UNIDO. The presentation will explore some of the dynamics of housing aspirations in Solomon Islands, and how traditional building methods and modern technology morph into hybrid forms of construction, and the significance this may have on the risks during cyclone events. Starting with a basic inquiry into traditional construction practices in Solomon Islands, Charles will discuss the work of Hybrid Technology, a not-for-profit NGO established in parallel with his own commercial architectural practice and how it developed small disaster-resistant buildings and explored discrete improvements to traditional buildings to successfully enhance cyclone resistance in Solomon Islands.

Biography UK trained and registered, Charles took up a position in a small architectural practice in Solomon Islands in the early 1980‟s. Following a major cyclone that killed over 100 people and destroyed several thousand homes, he assisted in the establishment of a local building materials council, and established a not for profit NGO “Hybrid Technology” to research and better understand traditional building practices and develop methods of building using local materials and available skills.

FIRE Lessons Learnt from the Recent Bushfires Mr Ralph Smith Branch Manager, Bush Fire & Environmental Protection, Fire & Emergency Services Authority of WA Since 2008 FESA has initiated a process following a bushfire event, were specialist staff analyse why houses were damaged and destroyed while other houses in the vicinity did not suffer any damage. In recent years, FESA has surveyed the bushland and houses in the Parkerville, Toodyay, Lake Clifton and Roleystone / Kelmscott fire affected areas. These surveys have been conducted on houses that were destroyed, houses that were damaged and houses that suffered no damage. The surveys have considered the building construction standards, as prescribed in Australian Standard 3959 Construction of buildings in bushfire-prone areas, the building protection zone (20 metre circle of safety), the hazard separation zone (up to 100 metres from the house) and the landscape zone vegetation, including the fuel load and the fire behaviour. Land use planning and the subsequent developments that occur have a significant effect on the emergency services that are required to try and protect those communities during a period of adversity. Frequently these developments occur in the bushland interface areas where there are continuous bushfire fuels within the landscapes. To assist developers, local government and State government agencies, FESA in partnership with the Department of Planning and the WA Planning Commission have developed and published Planning for Bush Fire Protection Guidelines. The 2010 guidelines have been developed in accordance with clause 6 of State Planning Policy 3.4 Natural Hazards and Disasters (SPP 3.4). The guidelines replace DC 3.7 Fire Planning and the first edition of Planning for Bush Fire Protection (2001), which were released by the WAPC and FESA in December 2001. A current and second edition of the Planning for Bush Fire



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Protection Guidelines, was released in 2010. The guidelines have been linked to Australian Standard 3959 – Construction of buildings in bushfire-prone areas which were published in 1999 and revised in 2009, 2010 and 2011. FESA provides advice on planning developments, separation distances between the house and the vegetation, construction standards, fuel loads and vegetation management. These are all factors in the survivability of houses attacked by a bushfire. The analysis by FESA seeks to identify why the houses are damaged or destroyed, if there are any weaknesses in the advice provided by FESA and how the damage or destruction can be avoided in the future.

Biography Ralph commenced working in the mid-1970s as a field officer with the Forests Department. Ralph worked for 26 years with the Forests Department and the Department of Conservation and Land Management. In 2001 Ralph moved to the Fire and Emergency Services Authority as the Manager of Wildfire Prevention. In 2004 Ralph was promoted to the position of Branch Manager of Bush Fire and Environmental Protection within the Fire and Emergency Services Authority. Ralph has extensive knowledge and understanding of bush fire behaviour and the impact that the fire behaviour can have on buildings and the environment. Ralph has served as an Australian Fire and Emergency Services Authorities Council (AFAC) representative on the technical working group for the “Australian Standard 3959 Construction of buildings in bushfire-prone areas”. Ralph has also been a co-author of the planning guidelines document “Planning for Bush Fire Protection” for both the 2001 and 2010 editions.

Ralph and his team have undertaken analysis of the complex bush fire behaviour and house loss assessments for all of the recent significant Western Australian bush fire events. Ralph was also invited to work with the Victorian‟s undertaking bush fire investigations during the Black Saturday fires. Ralph‟s work has been recognised with a number of State and National awards for bush fire arson prevention, and the research and publications associated with the “Bush Fire Management Guidelines for Western Australia”.

WATER

Coastal Hazards and the Design of Coastal Structures

Winthrop Professor Charitha Pattiaratchi University of Western Australia The importance and impacts of coastal hazards, particularly extreme events such as tsunamis and storm surges, has been illustrated very graphically through recent events such as the Japanese earthquake in March and Cyclone Yasi. During both of these events, extreme inundation of coastal areas occurred resulting in significant damage to infrastructure. In this presentation, different processes which contribute to coastal sea level variability leading to extreme events will be reviewed with an emphasis on Western Australia. It is shown that these processes occur over a range timescales ranging from seconds to centuries and are subject to long-term variability some of which, such as those due to astronomical tides, may be predicted. The action of the wind on the sea surface generates surface gravity waves with periods of the order of 10s. Although the swell waves are generated in the deeper ocean they have a major influence in coastal regions. Globally, the astronomical forces of the Sun and the Moon result in tidal variability with periods of 12 and 24 hours as well as tidal modulations with periods up to 18.6 years. In many regions, the effects of the tides dominate the water level variability – however, in regions where the tidal effects are small other processes also become important in determining the local water level. In this presentation, sea level data from Fremantle (tidal range ~0.5m), which has one of the longest time series records in the southern hemisphere, and other sea level recoding stations from Western Australia are presented to highlight the different processes ranging from seiches, tsunamis (generated through earthquakes and thunderstorms), tides, storm surges, continental shelf waves, annual and inter-annual variability. As the contribution from each of these processes is of the same order of magnitude they all contribute to the extreme sea levels.



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The majority of existing coastal infrastructure in Australia was designed to tolerate or at least survive occasional effects from extreme sea levels (e.g., 1 in 100 or l in 1,000 year prospects of inundation). As a result of coastal hazards, including mean sea level rise due to global warming, these designed tolerances will be exceeded with increasing frequency. The implications for changes in return periods on coastal infrastructure in Western Australia will be discussed.

Biography Charitha Pattiaratchi is a Winthrop professor of coastal oceanography at the School of Environmental Systems Engineering, the University of Western Australia. His research interests are in coastal physical oceanography and coastal sediment transport, using field and numerical modelling techniques. He obtained a BSc (joint honours in oceanography and applied mathematics), MSc and PhD (both in oceanography) from the University of Wales, Swansea, UK. He has been at UWA since 1988. Currently his affiliations includes Leader, Australian National Facility for Ocean Gliders, Node leader, West Australian Integrated Marine Observation System (WAIMOS), Chair, Numerical modelling, forecasting and scenario development working group of the Indian Ocean Tsunami Warning System, Chair, Physics of Estuaries and Coastal Seas International conference. He has supervised over 100 honours students and 30 postgraduate students and published over 100 refereed journal articles.

Note: Photograph of the speakers (during the panel session) below

(L to R): Prof Charitha Pattiaratchi; Mr Ralph Smith; Mr David Brunsdon; Mr Charles Boyle

Western Australia Division

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