Bridge Dynamics

Teknologidagene 2013

Clarion Hotel & Congress Trondheim

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Ole Andre Øiseth Department of Structural Engineering

Faculty of Engineering Science and Technology

Norwegian University of Science and Technology

Research activities Structural Dynamics

• Wind actions

– Tall buildings and cable-supported bridges

• Wave actions

– Submerged tunnels, and floating bridges

• Earthquake engineering

– Buildings and bridges

• Ice induced vibrations

– Ice induced actions on bottom fixed structures. Highly relevant for some bridges

• Vibrations induced by moving loads

– Interaction between pantograph and contact lines for electric railroad systems

– Bridge dynamics – Rail, Road and Pedestrian

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Education and structural dynamics

• Number of Master students supervised:

– 2010 – 13

– 2011 – 5

– 2012 – 26

– 2013 – 11

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Research activities Structural Dynamics

• Benefits of measurements

– Verify state of the art methods - for predicting dynamic response

– Discover phenomena - that can’t be modeled by the current state of the art

– Model uncertainty and structural reliability

– Inverse force identification

– Make new load models with improved accuracy

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Measurement of wind induced dynamic response

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Measurement of wave induced dynamic response

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The Hardanger Bridge measurement project

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The Hardanger Bridge measurement project

• Research questions:

– How well can we capture the dynamic response of the bridge?

• Vortex shedding induced vibrations (low mean wind velocities)

• Buffeting vibrations in strong wind

• Traffic induced vibrations

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The Hardanger Bridge measurement project

• Research questions:

– Are the methods used to characterize the wind field adequate for long span bridges in Norwegian fjords?

• Can the wind field be approximated as stationary?

• Can the wind field be approximated as homogeneous?

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The Hardanger Bridge measurement project

• The measurement system (CSI instruments)

– 9 Ultrasonic anemometers (Gill windmaster pro)

– 20 accelerometers (3 axis)

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• Linear frequency domain analysis

Development of computational analysis tools

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Transfer function

Wave loads

Wave induced response

Development of computational analysis tools

• Time domain analysis

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Wave loads

Wave induced response Time integration (linear/non-linear)

Development of computational analysis tools

• Flutter

– The mean wind velocity where the system is not able to dissipate energy.

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Research activities Structural Dynamics

• Wind actions

• Wave actions

• Earthquake engineering

• Ice induced vibrations

• Vibrations induced by moving loads

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