Date of Award

6-2012

Degree Name

Master of Science in Engineering

Department

Civil and Construction Engineering

First Advisor

Dr. Xiaoyun Shao

Second Advisor

Dr. Haluk Aktan

Third Advisor

Dr. Upul Attanayake

Access Setting

Masters Thesis-Open Access

Restricted to Campus until

6-15-2013

Abstract

Bridge Structural Health Monitoring (SHM) has rapidly become one of the main interests in civil engineering field. Inexpensive and efficient SHM method utilizing Wireless Sensor Network (WSN) is helping to facilitate the selection of the bridges that require maintenance. The changes to structural properties (i.e. stiffness) caused by damage (i.e. corrosion) will change the structural responses (i.e. acceleration responses) to ambient motions. Modal analysis algorithms applied to the vibration responses acquired through WSN provide the modal properties (i.e. natural frequency, modal shape and damping ratio) that will change with the changes in stiffness indicating possible existence of damage. Three output-only modal analysis algorithms: Stochastic Subspace Identification (SSI), Auto-regressive Moving Average (ARMA) and Fast Fourier Transform (FFT) were evaluated based on their accuracy and efficiency in extracting modal properties using two case studies. FFT was found to be the most accurate and consistent algorithm. The extracted modal properties of the Holland Bridge agree with the ones obtained from the Finite Element (FE) bridge model. The extracted damping ratios from different algorithms were not consistent. Recommendations on future research in bridge SHM using WSN and modal analysis algorithms are provided.

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