Threshold Determination Using Bi-hazard Fragility Curves for the Evaluation of Structural Health Monitoring of USHER Technology

Abstract

Structural Health Monitoring (SHM) is not new in the field of structural engineering and its application goes from the monitoring to evaluation of bridges, dams, buildings, and other similar structures. As per National Structural Code of the Philippines (NSCP) Volume 1[1-4], the Implementing Rules of earthquake recording instrumentation of buildings has been continually advancing, but not in the case of bridges and dams. The objective of this paper is to apply the established sensor-driven accelerometer developed by USHER (Universal Structural Health Evaluation and Recording) system in the evaluation of Padre Jacinto Zamora Bridge in Manila; specifically, to determine the proper installation of the developed accelerometer in the identified critical parts of the bridge. SHM addresses the problem of structural integrity assessment and help in assuring repair cost to a minimal. SHM helps quantify the strength of a structure by identifying the damage. Often evaluations are made using visual inspection and by age consideration. Most of the time, the use of this type of evaluation tend to be expensive. Repairs are not directed to the damaged component alone but the whole structure. Hence, the expenditure expands. SHM with the application of Micro-Electro-Mechanical Sensors (MEMS) will allow gathering of data that can be converted in the form of the structure’s modal properties (i.e. natural frequency, mode shape, and damping ratio) [6, 7]. Structural health is then determined and be ready to compare it to the structural model simulation results. A method was developed to incorporate seismic fragility curves [5] to determine the thresholds for the evaluation of the structural health. Capacity spectrum method was utilized to derive the seismic fragility function. A Monte Carlo Simulation was used to derive the flood fragility curves.