Fuzzy Risk Assessment Model for Prefabricated Bridge Construction Projects

Prefabricated construction is widely adopted in developing countries for infrastructure projects; however, the risks associated with prefabricated bridge projects are understudied. Therefore, this research aimed at identifying and assessing risks in prefabricated bridge construction projects, followed by the development of a risk assessment model. Risk factors associated with prefabricated bridge projects were initially identified through a comprehensive literature review and structured interviews with experts. Risk perceptions of industry practitioners and experts in Sierra Leone were collected using a questionnaire survey and case studies. Qualitative analysis of risks revealed a total of 21 critical risk factors (CRFs) where the top-five risk factors indicate uncertainties in the supply chain. These risks include ‘poor supply chain integration,’ ‘inadequate supplier capacity,’ ‘error in installation of precast component,’ ‘complex rectification and rework,’ ‘lack of experience of contractor in prefabrication,’ and ‘poor information sharing between stakeholders.’ Application of factor analysis revealed four underlying critical risk groups (CRGs) which embody the CRFs in the categories of ‘execution risks,’ ‘material and logistics risks,’ ‘stakeholder and supplier risks,’ and ‘economic and financial risks.’ A fuzzy synthetic evaluation (FSE)-based risk assessment model was developed which yielded an overall risk score of 3.67, while integrating all the CRFs, indicating an increased level of risk associated with the implementation of prefabricated bridge projects in Sierra Leone. Validation of the FSE model for risk assessment of three prefabricated bridge construction projects yielded a mean absolute percentage error (MAPE) of 11.758% and confirmed its utility for estimation of risks with high precision. This strongly indicates the robustness and reliability of the model for practical application in risk assessment of prefabricated bridge construction projects. This study provides decision-makers and contractors with a unique risk register for prefabricated bridge construction projects and offers valuable information regarding the critical risks that require careful consideration.