Operational modal analysis and finite element model updating of ultra-high-performance concrete bridge based on ambient vibration test

Abstract

The advancement of technology for accurate and dependable monitoring and evaluation of current bridge infrastructure conditions has become increasingly important in ensuring that bridge structures operate safely. Operational modal analysis (OMA) has been used to solve various engineering problems, including civil engineering structures, where OMA has been used to monitor systems on a global scale. Structural health monitoring (SHM) is a method of observing and assessing a process that involves sampling response measurements regularly to track changes in the material and geometric properties of structures. However, knowledge of massive structural health monitoring (SHM) data is poorly interpreted due to computational constraints and a lack of data analysis methodologies. By determining the structure's modal parameters, including the natural frequency and mode shape, this study applied ambient vibration testing to acquire vibration response measurements and thus determine the structure's dynamic characteristics. A comparison of three modal detection approaches (Frequency Domain Decomposition (FDD), Enhanced Frequency Domain Decomposition (EFDD), and Stochastic Subspace Identification (SSI)) was performed, and the mode shapes of each method were validated using the Modal Assurance Criterion (MAC) value to verify the accuracy of the results. On the basis of experimental data, a sensitivity-based updating method was used to justify and update the numerical finite element (FE) model of bridge structures. The difference between the updated FE and that measured for the first five dominant natural frequencies in this study was less than 5%. The updated model's minimum MAC value of 90% indicates that it was updated successfully. The updated dynamic parameter of the first dominant natural frequency (3.348 Hz) was used to figure out the structure's serviceability vibration limit state in accordance with EN 1991–2. The result was in the range that indicates that the bridge is safe for people to drive on.