A number of studies have been conducted in an effort to understand wave attenuation andsound response during installation of deep foundations. This research stems from the needto better understand the effect of vibration on freshly placed and maturing concrete within24-hours after initial placement. Construction activities create vibratory inducing forces,which unaccounted for or unmitigated, have detrimental effects to existing and newly in-placestructures. The differences between common construction vibrations, and those producedduring deep foundation construction, are the amplitudes and durations. The study focuses oneffects during the installation of deep foundations through vibratory methods and the age effectof the vibrations on freshly placed concrete. The installation followed the Florida Department ofTransportation (FDOT) guidelines. During the drilled shaft casing installation, vibration istransmitted from the source of installation to the surrounding soil causing ground motionaffecting the adjacent structures. The intensity of the ground motion and the severity of theinduced vibration depend on factors, such as soil type, form of amplitude-time history of thevibration, polarity of certain type of waves, and configuration of the adjacent structures. Thefield investigation monitored peak particle velocities during installation and their effect on freshlyplaced concrete. The principal findings from the field study were: (1) vibrations with peakparticle velocities of up to 2.5 in/sec do not cause damage to the fresh concrete at distances oftwo times the shaft diameter and beyond, and (2) in general, a spacing of three times the shaftdiameter is a safe specification for ensuring that shaft vibration does not damage the concrete.
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