Vibration Effects Attributable to Driving of PHC Pipe Piles

Abstract

To ensure the safety of adjacent 16.7-m-high concrete frame structures (cooling towers) and buried pipelines in service during installation of 83 prestressed high-strength concrete (PHC) pipe piles, the behavior of the ground, the buried pipelines, and cooling towers was monitored by a comprehensive instrumentation program. The field measurements included the following: (1) time histories of the particle velocities and corresponding Fourier spectra in three mutually perpendicular directions at various pile penetration depths and (2) vertical and horizontal movements of the buried pipelines caused by pile installation. Based on the analysis of the field data, the following major findings were obtained: (1) unlike the driving of prestressed concrete piles or cast in situ piles, the vibration velocity in the vertical direction was not greater than that in the plane during PHC pipe pile driving; (2) the amplitudes of the peak particle velocities were relatively independent of the pile penetration depths because of the complex soil conditions; (3) both the ground and the concrete structure experienced primarily high-frequency vibrations, which attenuated rapidly over time; (4) during the pile driving, only slight vibration amplification was observed at the upper levels of the existing concrete frame structure as a result of the soil-structure interaction—the concrete structure had a much wider frequency band (around 0–300 Hz) than the ground (around 0–100 Hz); and (5) the method of installing the piles close to the existing facilities before installing those a distance away effectively mitigated the potential adverse effects on the buried pipelines.