Obtaining Dynamic Parameters by Using Ambient Vibration Recordings on Model of The Steel Arch Bridge

Abstract

Operational Modal Analysis (OMA) is a one of the most popular method to extract the dynamic characteristics from ambient vibration response signals. In this study, the dynamic characteristics of a model of steel arch bridge with a bolt connection constructed in a 6.10 m span and 1.88 m height laboratory were determined by finite element method and operational modal analysis methods. Firstly, finite element model was created in SAP2000 software of model steel system and dynamic characteristic were obtained numerically. Then, accelerometers were placed where the displacements are high on points of the system and dynamic characteristics were determined by operational modal analysis method. The aim of this study is to obtain the dynamic parameters (frequency, damping ratio, mode shapes) of the model of the steel arch bridge accurately and reliably by operational modal analysis method by making use of ambient vibrations in the laboratory conditions. For this purpose, analytical analysis of the model of the steel arch bridge with finite element method and the dynamic parameters obtained as a result of the operational modal analysis of the model steel arch bridge were compared. Also, the modal assurance criterion (MAC) was used. Good compatibility was recognized between the results obtained for experimental and numerical procedures in terms of both the natural frequency and the mode of vibration. At the end of this study, reasonable correlation is obtained between mode shapes, frequencies and damping ratios. Analytical and Operational modal frequencies differences between 0.139 %–7.170 %.

Operational Modal Analysis on Bridges: A Comprehensive Review

“…With regard to bridges, vibration excitation can be achieved through eccentric rotating mass vibrators or an impulsive shaker [35]. On the other hand, OMA [36][37][38][39][40][41][42][43][44], also known as output-only modal analysis, ambient modal identification, or in-operation modal analysis, relies on vibration data collected while the structure is under its operational state. OMA becomes practical when the structure's size prohibits artificial excitation or when the system cannot undergo a complete interruption in operation.…”

“…This involves estimating the natural frequencies by counting zero crossings over time and determining damping ratios through logarithmic decrements from the normalized autocorrelation function [89]. Kasimzade et al [41] explored the modal parameters of a steel model bridge using the EFDD method, and the effectiveness of the method was proven in determining these parameters accurately for BSHM. Jacobsen et al [89] also employed EFDD to handle harmonic effects during modal extraction, resulting in more robust estimates of structural characteristics.…”

Modal Analysis of the Wind Turbine Planned to be Built in Mamurdağı Ground Conditions Using Finite Element Method

“…Knowing the dynamic parameters of the structures provides us with information about the situation that may occur before or after the structure. Experimental behavior of structures is investigated with experimental studies in structures vibrating with various factors [2] Investigation of the dynamic behavior of any structure can be investigated theoretically by constructing a finite element model and experimentally by using modal analysis methods [2,10,17]. In the literature review related to this publication, many studies using the finite element method have been reached.…”

“…In the literature review related to this publication, many studies using the finite element method have been reached. In some studies, such as some of the publications using the finite element method and guiding the author's work are as follows on the use of the finite element method were used [2,10,17] With all these knowledges, some these new studies has been carried out. Researchers have conducted many study on new methods [15,12, 7, 14, 6] The author also refers to these studies about the wind towers structures made.…”

Static and dynamic evaluation of a butterfly-shaped concrete-filled steel tube arch bridge through numerical analysis and field tests

“…They are important parameters for the dynamic performance and design of bridge structures, such as wind resistance, seismic design, and vehicle-bridge coupling vibration analysis. In general, the modal parameters of structure-free vibration can be solved 21,22 :…”