| The objective of this thesis was to compare different dynamic characterization approaches for full scale bridge structures to devise a rapid and reliable Structural Health Monitoring (SHM) program in the aftermath of a natural or manmade hazard. Present methods for structural condition evaluation of bridge structures rely heavily on on-site visual inspections of each structure by specially trained engineers and technicians. It has been proved in the literature that this current method is subjective, time consuming and manpower intensive, all of which are not suited for the critical conditions following a hazard event. This study focused on comparing three different full scale dynamic test methods on two in-service fundamentally different bridge structures to provide recommendations on achieving a reliable characterization of the structures, while keeping testing efforts at a minimum. The three dynamic field test included Operational Modal Analysis, or ambient vibration testing, and controlled input vibration testing using an instrumented impact hammer and an electro-dynamic mass shaker. The two bridge specimens tested were a Parker pony truss structure and a concrete deck on steel girders structure. The effectiveness and limitations of each dynamic testing and characterization strategies and data acquisition architectures, data processing techniques, and their optimal integration was systematically evaluated for each bridge structure. Specifically, modal flexibility was the main comparison tool within the dynamic testing, given that this parameter provides a global representation of the structure's response under dynamic loads such as traffic and ambient noise. It was concluded that Impact Vibration testing was the preferred dynamic characterization method for rapid and reliable for post hazard condition evaluation of both structures. |
