Structural health monitoring of a curved segment of an elevated railroad

Abstract

A new Metro line was opened in 2012 in Mexico City. The elevated portion of this line is located in an area of high seismic risk with compressible soft soil. The monitoring and analysis of the structural response has been done for both transitory events and long-term conditions using two interdependent systems and two sets of sensors. Structural health is estimated using a set of key parameters calculated from sensors installed on a curved portion of the elevated railway. The structural health has been assessed by defining four damage levels that are delimited by two load states: service and design. Since the installation of the monitoring system, 14 seismic events, more than 50,000 train passes and four years of long-term effects have been recorded. This paper presents the damage level observed and criteria used for its assessment. Also, the main observations derived from the analysis of data recorded by the monitoring systems over a four-year period are described. Structural properties and their change in time have been analyzed through a set of health indicators defined from the available sensors. Changes to these structural performance indicators have been also correlated to ambient temperature. Finally, the overall condition of the structure is assessed in light of the data recorded by the structural health monitoring systems.