Study of passive deck-flaps flutter control system on full bridge model. I: Theory.

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A Damage Detection Algorithm Utilizing Dynamic Displacement of Bridge under Moving Vehicle

A damage detection method is proposed, which utilizes dynamic displacement of bridge structures under moving vehicle. The problem is first elaborated with closed-form solution of dynamic displacement, which is decomposed into quasi-static component and dynamic component. Dynamic curvature is defined as second derivative of the dynamic displacement for detecting damage location and estimating damage extent. Damage is modeled by local reduction of stiffness in this paper. Numerical study was conducted on a simply supported beam to verify the proposed method. Vehicle model is analyzed with Newmark’s method using Matlab to obtain the contact force acting on the bridge. Beam model is established in commercial finite element software ABAQUS. The effects of road surface roughness and vehicle-bridge interaction are both considered in the analysis. In order to identify damage location and extent, dynamic curvature was calculated with midspan displacement. Parametric study on measurement noise level, damage location, damage extent, and multiple damage cases is performed, and the analysis results show both reliability and efficacy of this method in damage detection of bridge structures. At last, conclusions are drawn for its application to bridges in engineering practice

DETC2005-84477 AUTO-PARAMETRIC VIBRATION OF A CABLE-STAYED-BEAM STRUCTURE UNDER STOCHASTIC LOADS

ABSTRACT In this paper, auto-parametric vibration of a cable-stayed beam structure under stochastic excitation is studied. Linear as well as nonlinear coupling terms between the cable and beam is considered in a simplified model to capture of interaction of the cable's local motion and the beam's global motion. The general equivalent linearization method is applied to obtain the stochastic response. Results show that when the vertical excitation to the beam exceeds a critical value, the horizontal motions of the cable and beam are excited due to the autoparametric nonlinear coupling. The structural response possesses non-stationary characteristic, even though the load is stationary

Wind Resistant Design of Bridges in Japan: Developments and Practices

For long-span bridges, wind action is a dominant factor in their safety and serviceability. A large number of long-span bridges have been built in Japan over the past 30 years, and tremendous amounts of research and technical development have been accomplished in wind resistant design. This book is a compilation of the results of active research and development. Wind resistant design standards generated in Japan are described in the first few chapters. Then comes information such as design wind speed, structural damping, wind tunnel tests, and analyses, which provide the basis of the design standards. Wind-induced vibrations and their control of girders, towers, cables, and other features are explained with examples of field measurements. Comprehensive listings of Japanese experience in vibration control are also presented. Because achieving particularly dynamic safety against wind is still not an easy task, these data and information will be valuable assets for the wind-engineering and bridge-engineering communities