Subway Infrastructure Condition Assessment

Abstract

Public transit infrastructures nowadays face extensive deterioration and require large amount of capital expenditure to regain sufficient performance levels. According to one official U.S. government assessment, transit infrastructure is assigned a grade of D, which means “poor condition.” In the meantime, subway systems ridership is growing; therefore, it is crucial to assess the condition of such vital infrastructure, which greatly affects public safety. Transit providers need to create efficient management tools, including methodologies for the condition rating and performance evaluation of their assets. The objective of the present research is to develop a condition assessment model for subway stations and tunnels considering structural, electrical, and mechanical components. The condition is rated based on actual defects in which the Analytic Hierarchy and Networks Processes are utilized to estimate defect and component’s weights. A fuzzy scale is proposed to interpret the various condition grades. A customized Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method is utilized to develop an integrated infrastructure condition index for various components, stations, and tunnels. Data to determine weights were collected from experts through on-line surveys. The model is implemented in a case study, where the examined subway system reported good performance, and is tested through comparison with results obtained from existing models. This study is relevant to transit authorities, subway industry practitioners, and researchers.