"STRUCTURAL HEALTH MONITORING AND DAMAGE DETECTION OF A BRIDGE STRUCTURE"

Abstract

Bridges are essential links for transportation lifeline system. They should remain safe during and after devastating earthquakes. In this work dynamic measurements of the systems as they vibrate under the influence of ambient and service loads are used to characterize the structural condition at any given time. Damage is localized regardless of the environmental conditions that affect the structure's dynamic behavior. Based on these inferences a few methods that detects and locates the damage in civil structures which are used by researchers in this area are utilized by conducting an experiment on fixed beam, where in the free vibration response of the beam is used to calculate the modal parameters and hence damage indices are developed. By using the similar methodology while analyzing the data, the modal parameters of a railway bridge are extracted by conducting a health monitoring frame work with a gap of three months, where in establishing this procedure as a whole is the main aim of this dissertation. To extract modal parameters the data analysis is pursued using Frequency Domain Decomposition (FDD). The methodology is tested with eigen solution of a finite element model that represents a typical railway bridge. The research emphasizes realistic applicability to civil engineering structures in which only a few low vibrational modes can be measured with relatively high accuracy and also the higher modes are more sensitive to damage is being emphasized from this study. However, the proposed framework as a whole (or in part) is likely to perform well in other engineering