Substructure Identification for an Axially Loaded Member Using Local Vibration Modes

Abstract

Axially loaded elements play an important role in various civil structures. Knowledge of these crucial members is critical to health monitoring and performance assessment of a structure system in daily service or after a disaster. In the framework of substructure identification, a vibration-based method is proposed to evaluate the mechanical performance of a beam-like structural member by using multipoint dynamic measurements from acceleration, velocity, or displacement sensors. The major advantage of this method is its ability to simultaneously identify axial force, bending stiffness, and boundary conditions of the beam based on the local modal parameters of two or more modes, which is particularly favorable in the case that anchorage devices become complicated and uncertain through long-term service or after disasters like earthquakes. A laboratory experiment is conducted to validate the feasibility and effectiveness of the proposed method.