A Framework for Sustainable Structural Design Using Lifecycle Cost Analysis

Thesis Abstract

The increasing emphasis on sustainability in civil engineering highlights the necessity for innovative frameworks that integrate economic and environmental considerations into structural design processes. Traditional approaches predominantly emphasize initial construction costs, often neglecting long-term operational, maintenance, and decommissioning expenses, thereby undermining sustainability objectives. This study aims to develop a comprehensive framework for sustainable structural design anchored in Lifecycle Cost Analysis (LCCA), with specific objectives of identifying key cost components influencing sustainability, evaluating existing models, and proposing an integrative decision-making model tailored for various structural typologies. The research employs a mixed-methods approach, combining quantitative analysis with qualitative insights to ensure robustness and practical relevance. The research adopts a descriptive and exploratory research design. The population comprises 150 civil engineering firms and construction project managers across metropolitan regions, selected through stratified random sampling to ensure representative coverage of large, medium, and small enterprises engaged in public and private infrastructure projects. Data collection involved structured questionnaires and semi-structured interviews, validated through pilot testing on 20 industry practitioners, with established content validity and a Cronbach’s alpha of 0.87 confirming instrument reliability. Additionally, archival data on 50 completed projects with detailed lifecycle cost records were analyzed to contextualize findings. Quantitative data were analyzed using multiple regression analysis to determine the influence of various cost components on overall lifecycle costs, while thematic analysis was applied to qualitative interview data to identify prevailing themes regarding sustainable design practices. The study also develops a conceptual model grounded in stakeholder theory and the Lifecycle Cost Theory, integrating environmental impact assessments and cost-benefit considerations into structural decision-making. The model aims to facilitate architects, engineers, and project managers in choosing design alternatives that maximize sustainability benefits over the structure's lifespan. Results are expected to reveal significant correlations between upfront design choices and long-term lifecycle costs, highlighting the importance of incorporating sustainability metrics early in the design process. The findings are anticipated to demonstrate that applying the proposed framework can reduce lifecycle costs by up to 15% and improve environmental performance indicators, such as embodied carbon and energy consumption. This research substantially contributes to advancing knowledge in sustainable civil engineering by providing a structured, evidence-based decision-making framework that emphasizes lifecycle cost efficiency alongside environmental considerations. It bridges existing gaps by integrating sustainability principles systematically into structural design models and offering practical tools for industry practitioners. The framework’s applicability spans various structural typologies, including residential, commercial, and infrastructure projects, making it a versatile model for widespread adoption in sustainable construction practices. The main conclusion underscores the importance of adopting a holistic approach that incorporates lifecycle costing into structural design to promote sustainability. Recommendations include integrating the framework into standard design procedures, enhancing practitioners’ capacity through targeted training, and encouraging policy support for sustainable construction incentives. Future research should explore the adaptation of this framework in emerging construction technologies and assess its performance in different geographical and climatic contexts to enhance its global applicability. Overall, this study presents a significant step forward in operationalizing sustainable design principles in civil engineering through an analytically rigorous and practically feasible framework.