Identifying Modal Parameters of a Multispan Bridge Based on High-Rate GNSS-RTK Measurement Using the CEEMD-RDT Approach

摘要

This article aims to develop a hybrid approach of complementary ensemble empirical mode decomposition (CEEMD) and random decrement technique (RDT) for identifying the modal parameters (i.e., natural frequency and damping ratio) of structures using high-rate (50 Hz) global navigation satellite system and real-time kinematic (GNSS-RTK) measurement data. The framework of the proposed approach included two stages: (1) CEEMD was first used to derive a set of single-component signals, called intrinsic mode functions (IMFs); and (2) RDT was employed to extract the free decaying signals from the IMFs, including the main frequency information of structures. Subsequently, a three-story shear building model and an actual multispan bridge were used to validate the proposed approach. Additionally, a finite-element (FE) model of the bridge was built for comparing with the experimental case. Finally, the results indicated that the GNSS-RTK technique is capable of monitoring the dynamic displacements of multispan bridges with reliable accuracy. The proposed method performed better than the classical natural excitation technique-eigensystem realization algorithm (NExT-ERA) and stochastic subspace identification (SSI) algorithm-and was viable in practical applications.