Life Cycle Sustainability Assessment For Multi Criteria Decision Making In Bridge Design A Review

Sustainable design of infrastructures has become a major matter of study since the recent establishment of the Agenda 2030. This paper provides a systematic literature review on the use of multi-criteria decision making techniques used so far for the sustainable design of bridges. Special attention is put as well on how the reviewed studies assess the sustainable performance of bridge designs along their life cycle from the economic, the environmental and the social perspective. Although SAW and AHP are recurrently used in the sustainable assessment of bridges, the analysis of the most recent articles show that the application of TOPSIS and PROMETHEE techniques are gaining increasing relevance for such purpose. Most of the studies focus on the research of the construction and the maintenance stage of bridges. However, a need for further analysis is identified when it comes to the assessment of the impacts resulting from the End of Life cycle stage of bridges from a sustainable point of view. The use of intuitionistic and neutrosophic logic have been detected as emerging alternatives to the fuzzy approach of decision making problems.

Given the great impacts associated with the construction and maintenance of infrastructures in both the environmental, the economic and the social dimensions, a sustainable approach to their design appears essential to ease the fulfilment of the Sustainable Development Goals set by the United Nations. Multicriteria decision-making methods are usually applied to address the complex and often conflicting criteria that characterise sustainability. *e present study aims to review the current state of the art regarding the application of such techniques in the sustainability assessment of infrastructures, analysing as well the sustainability impacts and criteria included in the assessments. Analytic Hierarchy Process is the most frequently used weighting technique. Simple Additive Weighting has turned out to be the most applied decision-making method to assess the weighted criteria. Although a life cycle assessment approach is recurrently used to evaluate sustainability, standardised concepts, such as cost discounting, or presentation of the assumed functional unit or system boundaries, as required by ISO 14040, are still only marginally used. Additionally, a need for further research in the inclusion of fuzziness in the handling of linguistic variables is identified.

This paper proposes a methodology for the assessment of the sustainability among three different structural design alternatives for a single-family home. The response associated with each alternative has been measured using 43 indicators considering all stages of the life cycle. A decision-making model is carried out on the basis of a neutrosophic group analytical hierarchy process (NAHP-G) capturing the maximum information in terms of credibility, inconsistency and indetermination.

The present paper proposes a neutrosophic AHP completion methodology to reduce the number of judgments required to be emitted by the decision maker. This increases the consistency of their responses, while accounting for uncertainties associated to the fuzziness of human thinking. The method is applied to a sustainable-design problem, resulting in weight estimations that allow for a reduction of up to 22% of the conventionally required comparisons, with an average accuracy below 10% between estimates and the weights resulting from a conventionally completed AHP matrix, and a root mean standard error below 15%.

Essential infrastructures such as bridges are designed to provide a long-lasting and intergenerational functionality. In those cases, sustainability becomes of paramount importance when the infrastructure is exposed to aggressive environments, which can jeopardise their durability and lead to significant maintenance demands. The assessment of sustainability is however often complex and uncertain. The present study assesses the sustainability performance of 16 alternative designs of a concrete bridge deck in a coastal environment on the basis of a neutrosophic group analytic hierarchy process (AHP). The use of neutrosophic logic in the field of multi-criteria decision-making, as a generalisation of the widely used fuzzy logic, allows for a proper capture of the vagueness and uncertainties of the judgements emitted by the decision-makers. TOPSIS technique is then used to aggregate the different sustainability criteria. From the results, it is derived that only the simultaneous consideration of the economic, environmental and social life cycle impacts of a design shall lead to adequate sustainable designs. Choices made based on the optimality of a design in only some of the sustainability pillars will lead to erroneous conclusions. The use of concrete with silica fume has resulted in a sustainability performance of 46.3% better than conventional concrete designs.

The use of novel materials and new structural concepts nowadays is not restricted to highly technical areas like aerospace, aeronautical applications or the automotive industry, but affects all engineering fields including those such as civil engineering and architecture. The included contributions highlight the latest developments in design and manufacturing. Most high-performance structures require the development of a generation of new materials, which can more easily resist a range of external stimuli or react in a non-conventional manner. Particular emphasis is placed on intelligent structures and materials as well as the application of computational methods for their modelling, control and management. The book also addresses the topic of design optimisation. Contributions cover numerical methods, different optimisation techniques and new software. Optimisation problems include those related to the size, shape and topology of structures and materials. Optimisation techniques have much to offer to those involved in the design of new industrial products, as the appearance of powerful commercial computer codes has created a fertile field for the incorporation of optimisation in the design process of all engineering disciplines. The performance of structures under shock and impact loads is another area covered. The increasing need to protect civilian infrastructure and industrial facilities against unintentional loads arising from accidental impact and explosion events as well as terrorist attacks is reflected in the sustained interest worldwide. While advances have been made in recent decades, many challenges remain, such as developing more effective and efficient blast and impact mitigation approaches or assessing the uncertainties associated with large and small scale testing and validation of numerical and analytical models. The overall aim is to move towards a better understanding of the critical issues relating to the testing behaviour, modelling and analyses of protective structures against blast and impact loading. The studies contained in this volume were presented at the International Conference on High Performance and Optimum Structures and Materials Encompassing Shock and Impact Loading and address issues involving advanced types of structures, particularly those based on new concepts, and shock and impact resistance.

Environmental Life Cycle Assessment (ELCA) that was developed about three decades ago demands a broadening of its scope to include lifecycle costing and social aspects of life cycle assessment as well, drawing on the three-pillar or ‘triple bottom line’ model of sustainability, which is the result of the development of the Life Cycle Sustainability Assessment (LCSA). LCSA refers to the evaluation of all environmental, social and economic negative impacts and benefits in decision-making processes towards more sustainable products throughout their life cycle. Combination of environmental and social life cycle assessments along with life cycle costing leads to life cycle sustainability assessment (LCSA). This book highlights various aspects of life cycle sustainability assessment (LCSA).

The recently established Sustainable Development Goals call for a paradigm shift in the way that buildings and infrastructures are conceived. The construction industry is a major source of environmental impacts, given its great material consumption and energy demands. It is also a major contributor to the economic growth of regions, through the provision of useful infrastructure and generation of employment, among other factors. Conventional approaches underlying current building design practices fall short of covering the relevant environmental and social implications derived from inappropriate design, construction, and planning. The development of adequate sustainable design strategies is therefore becoming extremely relevant regarding the achievement of the United Nations 2030 Agenda Goals for Sustainable Development. This book comprises 11 chapters that highlight the actual research trends in the construction sector, aiming to increase the knowledge on sustainable design practices by highlighting the actual practices that explore efficient ways to reduce the environmental consequences related to the construction industry, while promoting social wellbeing and economic development. The chapters collect papers included in the Special Issue “Trends in Sustainable Buildings and Infrastructure” of the International Journal of Environmental Research and Public Health.