Barriers to Implementing Sustainable Engineering Solutions in Multidisciplinary Contexts: A Qualitative Study of Engineering Professionals in Tehran
This study aimed to explore the major barriers that hinder the implementation of sustainable engineering solutions in multidisciplinary project contexts from the perspectives of engineering professionals, project managers, sustainability consultants, and public-sector technical experts in Tehran. A qualitative descriptive design was adopted. Data were collected through semi-structured interviews with 24 participants selected through purposive maximum-variation sampling from engineering consulting firms, construction and infrastructure companies, environmental advisory units, energy-related organizations, and municipal technical bodies in Tehran. Participants had direct experience in designing, managing, evaluating, or implementing sustainable engineering solutions across multidisciplinary projects. Interviews continued until theoretical saturation was reached, which occurred after the twenty-first interview; three additional interviews were conducted to confirm conceptual adequacy. Interviews were audio-recorded with permission, transcribed verbatim, anonymized, and analyzed using thematic analysis. NVivo software was used to organize transcripts, develop initial codes, compare patterns across participant groups, and construct final categories. Analysis generated five main categories of implementation barriers: fragmented disciplinary logics and weak cross-functional communication; economic and procurement constraints; regulatory ambiguity and institutional inertia; limited sustainability knowledge, data, and lifecycle assessment capacity; and stakeholder misalignment, risk perception, and weak accountability. Participants emphasized that sustainable engineering solutions often fail not because of technical impossibility, but because engineering, financial, managerial, legal, and social actors evaluate project success through different criteria. High initial costs, short-term budgeting, uncertain incentives, fragmented approval procedures, limited access to reliable lifecycle data, and insufficient client demand weakened implementation. Sustainable engineering implementation in multidisciplinary contexts requires more than technical design competence. It depends on integrated governance, lifecycle-based evaluation, interdisciplinary communication, supportive regulations, financial incentives, stakeholder engagement, and organizational accountability. The findings suggest that sustainable engineering should be embedded into project planning, procurement, education, and performance evaluation systems rather than treated as an optional design feature.