DYNAMIC DEFORMATION MONITORING OF TALL STRUCTURE USING GPS TECHNOLOGY

Dynamic deformation monitoring of structures such as long bridges, tow ers, and tall buildings, for the purpose of determining structural vib rations, is now possible using global-positioning-system (GPS) technol ogy. Current non-GPS techniques for measuring structural vibrations (t hese include vibration measurement with accelerometers, vibration meas urement with a laser interferometer, and vibration measurement with an electronic distance measurement instrument) are first briefly outline d, with advantages and disadvantages noted. The specific application, measurement of structural Vibrations in the Calgary Tower, Calgary, Al berta, Canada, using GPS receivers in differential mode, is then descr ibed. The results show that the Calgary Tower, under wind loading, vib rates with a frequency of about 0.3 Hz in both north-south and east-we st directions. The 0.3 Hz vibration frequency measured On the Calgary Tower is within the range of 0.1 Hz to 10 Hz expected for structures o f this type. When the capability of GPS to monitor structural vibratio ns is verified by further tests, it could be adopted as a standard tec hnique.