Enabling Digital Transformation in Bridge Structure Damage Level Assessment Based on Decline in Natural Frequency Using Ambient Vibration Records

Abstract

Bridge structure condition assessments are critical for decision-making for bridge operation and maintenance. The natural frequencies of a structure depend on its global stiffness and weight. Therefore, the decrease in the natural frequency can be a global indication of structural damage conditions. However, the criteria for establishing a natural frequency threshold for judging the structure damage condition are still in question for engineers. In this paper, a method is proposed to find reference thresholds of frequency decline for the evaluation of bridge structural damage conditions using nonlinear incremental modal pushover analysis. The natural frequency thresholds obtained by the proposed method can be used in the system to automatically evaluate the damage and produce reports after each detected seismic event or at predetermined periods. The accuracy of the proposed method was verified by Eigenvalue analysis and nonlinear dynamic response analysis. In addition, this paper presents an integrated digital transformation system for bridge damage assessment. The system includes a wireless accelerometer, cloud integration, and edge computing to allow users to set up various damage assessment thresholds for warning and reporting when it detects damage or anomalies in structures.