Application Of FTA In Risk Analysis Of Civil Engineering

Construction is a complex and challenging process which, inevitably, is exposed to various elements of uncertainty. Construction risks may impact the project cost, schedule and scope in achieving a quality product on time and within budget. At present, the ability to identify and assess these construction risks is inadequate which is attributed to relatively lagging and incomplete information, but more importantly, is due to the lacking of an effective tool. Widely used in system reliability studies, Fault Tree Analysis (FTA) is one of the fundamental tools of reliability and risk analysis used to assess vulnerability and guide in redeploying resources to optimize the control of risk. FTA provides a mechanism for effective construction risks evaluations.This paper provides an overview on the theory and fundamental concept of FTA, examines the benefits, disadvantages and functionality of FTA, and presents a visual diagram and logic model to demonstrate FTA as a mechanism for qualitative and quantitative evaluation. FTA diagrams are developed for the two commonly used foundation support systems that have high number of construction accidents and injuries - Soldier pile and Soil nailing, as well as the most popular Soil-Mixed-Wall (SMW) support system. Both qualitative and quantitative evaluations are developed for Soldier pile which embarks a practical application of FTA in construction risks assessment. In reference to the philosophy behind the study of Failure, this paper examines the construction risks knowledge sharing possibility based on project characteristics, risk characteristics, and existing risk assessment tools. It is concluded that an effective approach to enhance the construction risk assessment ability is through the construction risk knowledge base processing, systematizing and sharing with the public while using FTA as a carrier for knowledge sharing. A preliminary FTA-based Risk Assessment System for Construction is established based on information technology using sub-divisional construction categories as the building blocks and FTA as the key evaluation model. This system has the ability to save, search, add and modify FTA model, to quickly produce a FTA model that matches with the actual construction project data, to automatically perform qualitative and quantitative evaluations of construction risks in the FTA model. This system is a breakthrough in applying the FTA theory to construction risks management and could be widely used in the construction industry.