Sustainability and Adaptable/Flexible Infrastructure
Infrastructure is basically intended for long-term operation and can be worth a large percentage of peoples' and governments' wealth. Future changes with large inherent uncertainties attached may cause infrastructure to face unanticipated circumstances in terms of demographic or technological changes resulting in changed needs and wants, or climate change manifested by increased temperatures, altered rainfall patterns or extreme weather events and sea level rise. This may lead to inefficient or obsolete infrastructure, creating the need for adaptation to ensure the continuing relevance of the existing infrastructure providing desired services to society. Infrastructure adaptation causing enormous expenditure, resource consumption and possible disruption to services represents a significant sustainability issue.Given that infrastructure can be adapted to change some way into the future, but with different extents of effort, expenditure and sustainability impacts, developers are caught in a dilemma as to whether to design infrastructure for adaptability or flexibility. As an alternative to conventional design, some adaptability features can be incorporated ab initio in infrastructure design with the view that adaptation may (but not necessarily) take place in the future, depending on future circumstances. Adaptation is thus a key issue with existing infrastructure, as well as the design and construction of new infrastructure.The literature acknowledges infrastructure adaptability to enhance sustainability, but falls short in valuing the sustainability and even the financial performance of adaptable infrastructure. The literature on infrastructure adaptability is also criticised as a result of some perceived confusion due to numerous, and sometimes divergent, interpretations and categorisations. Hence, this thesis i) adopts a holistic approach, giving infrastructure adaptability and flexibility a genuine, universal interpretation and clarifying its relationship with the concept of sustainability valuation; ii) quantitatively evaluates the sustainability of adaptable infrastructure using an existing, easy-to-use Real Options Analysis (ROA) combined with a Life Cycle Assessment (LCA) approach for social and environmental analyses; this approach is suitable for a comparative study between designed-in and non-designed-in adaptable infrastructure; iii) presents a new approach that advances the sustainability valuation of adaptable infrastructure; this approach extends ROA to the sustainability context using Social/Environmental Costing (SEC). Different case examples from the Australian context are utilised to illustrate the approaches proposed in the thesis.The thesis gives a conceptual benchmark and improves the understanding of infrastructure adaptability such that practical solutions for adaptation can be sought more effectively. In addition, it provides rational, easy-to-use methods for establishing the viability of adaptable infrastructure from a sustainability viewpoint. The methods are also compatible with those commonly used in practice, suitable for engineering applications and capable of accounting for investors' preferences. The thesis will thus be of interest to both academics and practitioners involved in the construction industry and contemplating prolonging the useful life of infrastructure through adaptation over time.
