Title: Predicting Near and Far Field Ground Vibration for Equipment Foundations

Author(s): David L. Pederson, Anthony J. Baxter and Carl A. Nelson

Publication: Symposium Paper

Volume: 348

Issue:

Appears on pages(s): 1-18

Keywords: attenuation, damping, dynamic, elastic half-space, equipment, far field, foundations, frequency, material damping, near field, response, shear modulus, shear wave, stiffness, vibration

DOI: 10.14359/51732676

Date: 3/1/2021

Abstract:
This paper discusses steps for both computing vibration from equipment foundations using the elastic halfspace theory and then computing the decrease in vibration amplitude from the foundation to receivers. The steps are demonstrated on an existing foundation at a project site in Ohio that was subjected to dynamic loading from a hydraulic vehicle test rig. Several approaches are discussed to estimate the dynamic shear modulus of different soils, along with a methodology to establish an equivalent dynamic shear modulus for soils with varying shear wave velocities. Vibration transmission through the soil can affect people and sensitive equipment both near and far from the source. This paper shows a hybrid method and an SRSS method to compute the vibration attenuation through the near field and far field. The calculated results for this site were found to be very close to the measured values. Finally, vibration levels are compared for variations in stiffness, damping and attenuation to evaluate the sensitivity to calculations and/or field measurements. Variations in stiffness result in a nearly proportional change in vibration level while variations in damping and attenuation produce relatively small changes in the results.