Investigation of the Dynamic Behavior of a Super High-rise Structure using RTK-GNSS Technique

Super high-rise structures have a significant deformation under ambient excitations such as earthquake and wind, which may lead to structural instability and even damage. To capture the dynamic characteristics of a super high-rise structure under construction (i.e., Tianjin 117 tower), Real Time Kinematic - Global Navigation Satellite Systems (RTK-GNSS) sensors are employed to derive the horizontal displacement of the structure. Considering the defects in measurement accuracy of RTK-GNSS sensors, a Type 1 Chebyshev high-pass digital filter is firstly employed and thus the output results are smoothed. Subsequently, based on the smoothed signals, the natural frequencies and the corresponding damping ratios are extracted via FFT (Fast Fourier Transform) and RDT-LDM (random decrement technique combined with logarithmic decrement method). It is found that the results from the field measurement coincide with the numerical simulation. Finally, the structural parameters are successfully obtained and illustrated graphically.