Developing a risk assessment method for complex pipe jacking construction projects

Pipe jacking (PJ) construction is a highly complex and uncertain process so that performing an accurate risk assessment is essential to the success of a project This study presents an innovative risk assessment model which combines fuzzy inference with failure mode and effect analysis (FMEA) to improve the effectiveness of existing risk assessment methods for pipe jacking construction. The proposed model maps the relationship between occurrence (O), severity(S), and detection (D) with the level of criticality of risk events in three steps: fuzzification, fuzzy rule-based inference, and defuzzification. A case study of a PJ construction project for water transmission in Shanghai, China is presented to demonstrate and validate the proposed method. A total of 31 potential risks was identified according to the PJ construction procedure and two-round Delphi questionnaire surveys. By using the proposed fuzzy-FMEA approach, the most critical risks in the PJ construction process can be identified, in particular, the shaft structure construction, jacking operation, and steel pipe segments welding. The proposed method overcomes the inherent weaknesses of traditional FMEA method and provides a reliable and distinguishable risk ranking system by properly reflecting the complexity of PJ construction environment The study also provides a comprehensive risk identification and evaluation tool for industrial practitioners who manage or involve with PJ construction projects. (C) 2015 Elsevier B.V. All rights reserved.