Strain-based monitoring methods for beam-like structures

Abstract

In this thesis Structural Health Monitoring (SHM) is defined as the process of periodically

or continuously measuring structural parameters over time and the consequent

analysis, with the aim of providing actionable information on structural performance.

This work is motivated by the need for network-wide SHM of typical structures.

Strain based SHM methods are explored with the main focus on the location of neutral

axis and the deformed shape of beam-like structures. SHM methods for evaluation of

these two parameters are developed, including detailed uncertainty analyses. Additionally, an exploration of several other parameters is presented through a case study. Strain data from two full-scale in-service structures, a large-scale test structure, and a laboratory specimen were used to validate the methods and assess their limitations.

The main conclusions are that: 1) repeated short-term measurements are ideal,

since they are less influenced by temperature and rheological effects; 2) the neutral

axis location varies in healthy structures and it is sensitive to damage and other

unusual structural behaviors; 3) uncertainty in the deformed shape was predicted

prior to data acquisition; and 4) for vertical displacement evaluations, a detailed

analysis of the boundary conditions is necessary.