Parallel 6 – Climate adaptation engineering for built infrastructure

Chair: Mark Stewart


 

Economic Assessment of Climate Adaptation Strategies for Design of New Housing (918)

Mark Stewart 1

  1. The University of Newcastle, Callaghan, NSW, Australia

An important climate adaptation goal is quantifying the costs and benefits of adaptation strategies (retrofitting, strengthening, enhanced designs) for built infrastructure – we define this as ‘climate adaptation engineering’. The paper will describe how risk-based approaches are well suited to optimising climate adaptation strategies related to the design and maintenance of new and existing infrastructure.

Risk-based decision support is described to assess the risks and economic viability of climate adaptation measures. An important aspect is assessing at what point in time climate adaptation becomes economically viable, and decision preferences for future costs and benefits (many of them intergenerational). Stochastic methods are used to model infrastructure performance, effectiveness of adaptation strategies, exposure, and costs. The concepts will be illustrated with current research of risk-based assessment of climate adaptation strategies including designing new houses in South-East Australia subject to extreme wind events. Increasing the design wind classifications in the AS4055-2012 for all new housing can lead to risk reductions of 50-70%, at a cost of little more than 2% of house replacement value. If risk reduction is over 70%, discount rate is 4%, and there is no change of climate, the break-even analysis shows that adaptation is cost-effective for Sydney if the adaptation cost is less than 3-5% of house replacement cost. This anticipatory adaptation measure will help pave the way for more efficient and resilient infrastructure, and help ‘future proof’ existing infrastructure to a changing climate.


 

Basalt fiber strengthening structural insulated panel subjected to windborne debris impact (919)

Wensu Chen 1 , Hong Hao 1 , Qingfei Meng 1

  1. Curtin University, Bentley, WA, Australia
With the climate change, cyclone intensity and occurrence increase. Typhoon Haiyan in 2013 with wind speed of 315 km/h devastated Philippines. It was found that windborne debris contributed to the devastating damages in many cyclones. The debris penetration through building envelope typically induces a differential internal pressurization which contributes to the increased loading of the building’s roof and leeward walls, ultimately leading to building failures. In the building industry, structural insulated panel (SIP) with oriented strand board (OSB) skins is becoming popular in the current and predicted market due to its sustainability feature. In the previous study by Chen and Hao (2014), SIP panels with OSB skins were tested according to the Australian Standard (AS/NZS1170.2:2011). It was found that all the tested specimens failed at impact velocities around10m/s, which is substantially lower than the required projectile impact velocity of 44m/s at Cyclone Region D. To increase the capacity of the existing SIP panels and minimize possible damage, engineering adaptation method should be explored to strengthen the panel in a “green” way whilst considering performance and cost. Basalt fiber, similar to carbon fiber and fiberglass, is a promising solution in terms of its shock resistance capacity and low cost. Laboratory tests will be carried out on the SIP panels strengthened by basalt fiber using a pneumatic cannon system. The perforation resistance capacity of strengthened panels will be assessed by comparing the previous testing results. The capacity of basalt fiber strengthened SIP panels in resisting windborne debris impact will be examined.

 


Loading of roof to wall connections in a timber structural system (920)

Navarathnman Satheeskumar 1 , David Henderson 1 , John Ginger 1

  1. James Cook University, Townsville, QLD, Australia
The roof to wall connection is designed to transfer the uplift and lateral loads during strong windstorms in a building structural system. In Australia, generally roof trusses are tied with triple grip connection to the wall top plate. Hence, this study focused on the roof to wall triple grip connection response loading. The numerical model analysis method is an alternative method to assess the roof to wall connection response and uplift capacity in design practice. A three dimensional (3D) triple grip connection model was assembled and subjected to static load by using ABAQUS (6.12-3) finite element software as shown in Figure 1. In addition this study investigated the single nail joint response to develop the roof to wall triple grip connection model. Moreover, this study sought to investigate the construction errors to predict the up lift capacity of roof to wall triple grip connections. This study has found the significant reduction in the uplift capacity of roof to wall triple grip connection, when it is assembled with construction errors (i.e. a nail missing on the truss and top plate).

Built Environment under Changing Climate: Enabling Adaptation by Standard, Planning and Policy Nexus Development (921)

Xiaoming Wang 1 , Samiul Hasan 1

  1. CSIRO, Highett, VIC, Australia
IPCC 5th Assessment Report on Climate Change for Policymakers further affirms the continuing trend of global warming and their observed geophysical effects (IPCC, 2013). Thus, it is important to understand the impacts of changing climates and increasing disaster risks on our built environment, in particular, develop adaptation pathways to mitigate the impacts through the nexus of climate-conscious design standards, planning and policies. Firstly, the implications of climate change to built assets is presented, and an approach to develop resilient engineering structures by enhanced design standards to maintain durability under changing climate is then introduced. Secondly, an integrated approach is demonstrated to develop timely and spatially targeted regional coastal planning to mitigate the impacts of coastal inundation under sea level rise and increasing extreme winds. Finally, a large-scale reactive and proactive intervention options to mitigate coastal inundation, extreme winds and bushfire at a national scale are examined in terms of cost and benefit for the development of national adaptation policies.

Application of phase change materials to improve indoor comfort during extreme heat waves in Australian cities (1095)

Sayanthan Ramakrishnan , Md Morshed Alam 1 , Xiaoming Wang 2 , Jay Sanjayan 1 , John Wilson 1

  1. Swinburne University of Technology, Hawthorn, VIC, Australia
  2. Commonwealth Scientific and Industrial Research Organisation (CSIRO), Melbourne, VIC, Australia

 Incorporation of phase change materials (PCM) into building envelope is found to be an innovative and effective way of decreasing the energy consumption and greenhouse gas emission in the building sector. In addition, isothermal energy storage nature of PCM could improve the occupant comfort and reduce the potential heat stress during extreme heat waves by cutting down the peak indoor temperature which, in turn, will result in reduced heat related mortalities. Therefore, this study investigated the effect of PCM in reducing potential heat stress risks in naturally ventilated residential buildings during heat waves using building simulation software EnergyPlus. The 2009 weather data of Melbourne, which is well known for the heat waves, has been used for the simulation. Discomfort Index (DI) has been used as an indicator for the heat stress which has three different categories: Mild, Moderate and Severe. From the simulation, it was observed that appropriate selection of PCM according to local climate conditions in combination with better ventilation design could reduce the hours of Discomfort Index by up to 32% and 29% in moderate and severe ranges respectively. But these figures were reduced to 7 % and 10 % for PCM enabled building without night ventilation. In conclusion, it is foreseeable that PCM with suitable phase transition properties would have potential for minimizing the effect of heat waves, on the occupant health and comfort in Australian residential buildings. However, proper building design is critical for the effective use of phase change materials.


Cost-Effectiveness of Climate Adaptation Strategies for the Design and Management of Timber Power Distribution Poles (922)

Mark Stewart 1 , Paraic Ryan 1 , Nathan Spencer 2

  1. The University of Newcastle, Callaghan, NSW, Australia
  2. URI Engineering Pty Ltd, Newcastle, Australia

There are approximately five million timber power distribution poles in service across Australia worth $11 billion. Annual maintenance costs exceed $30 million for the eastern states of Australia. The Australian power distribution network constitutes an important element of the country’s urban and coastal infrastructure. Despite the scale of this infrastructure asset, limited research has been carried out to better enhance maintenance and management efficiency. In particular, there is a paucity of research utilising probabilistic methods to examine the vulnerability and reliability of Australian timber power poles under a changing climate.

This paper sets out to examine the vulnerability and reliability of Australian timber power poles under current and future climatic conditions. The hazards of interest are storms and tropical cyclones, and timber decay – both of which may worsen due to a changing climate. Monte-Carlo stochastic methods are utilised to estimate spatial and time-dependent economic risks or expected losses up to the year 2100 for various climate change scenarios. Adaption strategies aimed at mitigating possible increases in damage risk due to climate change include larger pole sizes, changes in timber durability, changes in inspection frequency and techniques, and changes in pole replacement criteria. The cost-benefit analysis of these adaptation strategies considers material and installation costs, inspection, maintenance and replacement costs, and direct and indirect damage costs. It was found that net benefit is maximised by a range of adaptation strategies, and that the optimal strategy depends heavily on region specific vulnerabilities.