Risk assessment of green infrastructure using failure mode and effect analysis: a case study of green wall projects across the project lifecycle

Sustainability is a fundamental principle in contemporary architecture. In this context, green walls (GWs) are a type of green infrastructure (GI) that provides sustainable design solutions, but they come with specific risks during the project lifecycle. The study aims to assess and prioritize the potential failure modes of GW projects across the project lifecycle by using Failure Modes and Effects Analysis (FMEA). To achieve that, design principles for GWs were discussed and classified according to the project’s lifecycle, and stakeholders for GW projects were analyzed. Then, 53 failure modes were identified, derived from GW's design principles across project phases. These failures were assessed according to severity, occurrence, and detection by creating an electronic questionnaire directed to various stakeholders. The questionnaire result was statistically analyzed, and failures were ranked after calculating the relative importance index (RII). Finally, failures were classified as high, medium, and low according to the Risk Scale Matrix. Results showed that the Monitoring and Controlling Phase is the most critical phase, where most of the high-ranked failures occur, followed by the Planning and Execution Phases with nearly equal percentages, then the Initiation Phase. This assessment outlines the failures related to the absence of implemented GW design parameters. Lifecycle-based FMEA analysis methodology enhances the technical reliability and sustainability performance of GW systems throughout their lifecycle and informs comprehensive construction risk studies. It highlights the stakeholders’ role in each project phase to assist decision-makers in prioritizing design considerations related to derived failure modes.