SYSTEM IDENTIFICATION OF A PEDESTRIAN BRIDGE FOR STRUCTURAL HEALTH MONITORING

Abstract

Damage Detection and Structural Health Monitoring has always been of great importance for civil engineers. Vibration based Damage Detection have several advantages compared to Traditional Methods of Non Destructive Evaluation like GPR, Ultrasonic Testing as they give a global response and are feasible for large structures. Damage Detection requires a comparison between two systems states the baseline or ‘healthy state’ i.e. the initial modal parameters, and Damage Detection. System Identification is carried out on a Pedestrian Bridge, measuring the dynamic response using six MEMS triaxial accelerometers. An output only method of modal analysis, Frequency Domain Decomposition algorithm is used to obtain the modal properties i.e. natural frequencies and mode shapes. FDD algorithm is coded on MATLAB and then verified and validated using lab scale beam. The system identification results are compared with finite element model of the Bridge using the commercial software ABAQUS. Good comparison was found out between the FE model and SI results. Keywords: Vibration Based Damage Detection, System Identification, Finite Element Modelling, MEMS accelerometers, Frequency Domain Decomposition