BRIGE: Continuous Structural Health Monitoring Framework for Bridge Structures

Tufts University, Medford MA

Investigators

Abstract

This Broadening Participation Research Initiation Grant in Engineering (BRIGE) provides funding for the development of a probabilistic continuous structural health monitoring framework. The novel framework will allow structural damage to be estimated as a loss of stiffness in probabilistic terms. The framework permits estimation of confidence in damage identification results as a function of uncertainty in the identified modal parameters which are directly calculated from continuous measurements. This new framework will be applied to a prototype footbridge (Dowling Hall Footbridge) located at the Tufts University campus. The footbridge is exposed to a wide range of environmental conditions and is large enough to exhibit complex structural behavior, providing an opportunity for a realistic assessment of structural integrity in the presence of varying environmental effects. As part of this framework, modal parameters of the Dowling Hall Footbridge are extracted based on the low-amplitude ambient vibration response measured using accelerometers and strain gages. Separation methods are then used to remove the effects of changing environmental conditions (temperature and relative humidity) from the identified natural frequencies. The continuous stream of identified natural frequencies, mode shapes, and their statistical characteristics are fed into a recursive Bayesian finite element model updating algorithm for probabilistic damage identification. If successful, the results of this research will improve the accuracy and confidence of damage detection algorithms, thus permitting enhanced monitoring and maintenance of infrastructure by providing a more effective engineering basis for better allocation of limited financial resources. In addition, the prototype continuous monitoring system provides a live, cross-disciplinary laboratory for integrated research and teaching in health monitoring of civil infrastructure systems. During this project, participation of students from underrepresented groups will be promoted through K-12 outreach and undergraduate research.