Date of Award

Fall 2012

Project Type


Program or Major

Civil Engineering

Degree Name

Master of Science

First Advisor

Erin Bell


The neutral axis of a composite bridge girder provides information relating to the health of both the girder and the concrete deck. Using bonded foil strain gauges, this location may be a useful Structural Health Monitoring (SHM) metric. SHM is an emerging tool that will create safer and more reliable bridge systems. By leveraging technology to investigate the way a structure behaves and degrades over time, the engineering community will gain valuable insight for developing more resilient bridges and can be alerted to damage when it occurs. This research used bonded foil strain gauges to determine neutral axis locations at the Bagdad Road over US Route 4 Bridge in Durham New Hampshire. The locations were determined to be between 32.35 to 32.39 inches and 30.45 to 33.08 inches from the bottom of the composite section. The value was reasonably close to the position located using transformed section properties of an undamaged section, calculated to be at 31.73 inches from the bottom of the section.

This thesis was also used as a means to record the SHM system design process and to evaluate equipment for potential future SHM research projects that the University of New Hampshire (UNH) may be involved with. The methods of installation and data processing are included. Finally, future work is recommended that may further develop strain-based SHM monitoring supported by conclusions based on information and observations collected throughout the research.