Finite Element Analysis and Ambient Vibration Test of the Arch Type Steel Highway Bridges

Abstract

In this paper, it is aimed to determine the dynamic characteristics of highway bridges using finite element analyses and ambient vibration tests. A modern steel highway bridge which has arch type structural system with 216 m total length and located in the Ayvacik county of Samsun, Turkey is selected as an application. Because of the fact that the bridge connects the villages which are separated with Suat Ugurlu Dam Lake, it has a major logistical importance for this region. The construction of the bridge is completed in 2009 and opened the traffic. An analytical modal analysis is performed on the developed 3D finite element model of the highway bridge to provide the analytical frequencies and mode shapes. The experimental measurements are carried out by ambient vibration tests under traffic loads. Vibration data are gathered from bridge deck. Measurement time, frequency span and effective mode number are determined by consider similar studies and literature. Enhanced Frequency Domain Decomposition method in the frequency domain and Stochastic Subspace Identification method in the time domain are used for the output only modal identification and dynamic characteristics such as natural frequencies, mode shapes and damping ratios are determined, experimentally. At the end of the study, analytically and experimentally identified dynamic characteristics are compared with each other. A good agreement is found between mode shapes, but some difference in natural frequencies.