Scale Normalization of Geotechnical Sustainability Assessment Tool (Geo-SAT) Using Multiple Criteria Decision Analysis

Abstract

Owing to major worldwide issues like global warming, carbon footprint, natural resource depletion, etc., Sustainable Development (SD) has become an imperative topic of the current era, specifically in the construction industry due to its drastic impacts on resource usage and their depletion. Geotechnical engineering, being preliminary in any construction project, is of paramount importance for practicing sustainable development. Moreover, assessment of construction activities from the beginning is essential to determine their impacts on economy, society, and environment i.e., three pillars of sustainability. Therefore, to incorporate sustainability in geotechnical engineering, an indicator-based sustainability assessment tool called Geotechnical Sustainability Assessment Tool (Geo-SAT) was developed. Geo-SAT considers all its indicators generic and equal in weightage which results in skewness. Thus, the tool does not reflect the true effect of indicators on sustainability for any construction project. This creates a need for tool normalization in terms of scale. In this research, 32 engineering specific, out of 171 indicators of Geo-SAT have been scale-normalized using Multiple Criteria Decision Analysis (MCDA) technique. MCDA implies experts’ opinion in decision making which incorporated the grass-root level effects of sampled indicators for achieving sustainability. A questionnaire is developed for this purpose to record the experts’ assigned weightages for indicators across project life cycle stages of feasibility, design, award, mobilization, construction and monitoring. Multiple Attribute Value Theory (MAVT), a sub-technique under MCDA, is then used for analysis as it provides pairwise comparison between indicators and project life cycle stages. Using the resulted weighted averages, the existing Geo-SAT is normalized to an improved metric for the sustainability assessment of sixXI different construction projects of geotechnical importance i.e., dams, tunnels, slope stability, bridges, buildings, and pavements. The indicator of ‘quality control during construction’ weighted highest among all sampled indicators for all the project types with weighted percentages of 4.8%, 5.2%, 6.0%, 6.0%, 6.3% 6.4% for dams, tunnels, slope stability, bridges, buildings and pavements respectively. Likewise, certain project specific indicators are categorized under scale normalized Geo-SAT. These percentile and project specification of indicators will increase the reliability and reduce skewness of sustainability assessment and development.