THE APPLICATION OF TRANSFER FUNCTIONS IN THE PREDICTION OF STRUCTURAL RESPONSE TO BLAST INDUCED GROUND VIBRATION

摘要

This paper outlines the theory behind transfer functions and illustrates their application in the prediction of structural response to blast induced ground vibration.rnThe ability to predict the response of a structure to a recorded ground vibration is desirable for a number of reasons.rn1. Structural or cosmetic damage often occurs, or is alleged to have occurred, away from the location at which vibration has been monitored.rn2. Humans or sensitive equipment likely to be affected by vibration are also often some distance from the monitoring location.rnExisting techniques used for structural response prediction include :-rn3. PPV ratio/amplification.rnThis approach is overly simplistic and only predicts the PPV and not the whole vibration response.rn4. Lumped Mass Models.rnThese techniques assume structures act as lumped mass systems and also require a good deal of expertise to produce the full vibration response.rnThe technique of transfer functions overcomes these problems by measuring the actual response of each structural monitoring point relative to a fixed location outside of the structure. This response being expressed as a function of amplification and phase against frequency. Once established a transfer function can be used to predict the vibration at the structural location from the vibration recorded at the fixed location outside of the structure.rnThe application of this technique to structural response prediction is illustrated with three case studies associated with vibrations from surface mine blasting.rn1. A simple shaking table model.rn2. Soil/foundation response.rn3. Typical U.K. domestic house.rnThese case studies are used to illustrate how transfer functions are calculated and their limitations in use by comparing actual and predicted responses.