Comparing Direct Observation of Torsion with Array-Derived Rotation in Civil Engineering Structures

Area of Science:

• Geophysics
• Structural Engineering
• Seismology

Background:

• Buildings are equipped with translation sensors to monitor structural health.
• Rotation sensors are less commonly used for structural analysis.

Purpose of the Study:

• To analyze building rotation rates using a combination of translation and rotation sensors.
• To compare acceleration/rotation ratios with seismic wave velocities.
• To explore applications in building imaging and structural integrity monitoring.

Main Methods:

• Installed a BlueSeis-3A rotation sensor at the top of Grenoble city hall for over 24 hours.
• Analyzed ambient vibrations, translation accelerations, and rotation rates at the building's top and bottom.
• Compared acceleration/rotation ratios with seismic wave velocities derived from seismic interferometry.

Main Results:

• Detailed analysis of translation accelerations and rotation rates over time.
• Comparison of building response characteristics derived from different sensor types.
• Established a link between acceleration/rotation ratios and seismic wave velocities.

Conclusions:

• Rotation sensing provides valuable data for understanding building dynamics.
• This approach offers potential for advanced building imaging and continuous structural health monitoring.
• Further research can explore the contribution of rotations to overall structural response.