Dynamic characteristics of ground motions due to blasting

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Abstract
There is considerable evidence that more rational damage criteria need to be generated with regard to low-rise structures subjected to seismic ground motions. There is not sufficient basis for specifying a maximum ground particle velocity criterion, such as 2 in/sec. A peak ground velocity guideline does not currently take into account a number of important parameters, including the predominant frequencies of the ground motion excitation and the structure being excited. Although a number of states have adopted peak-velocity criteria, such criteria have been ruled inadequate in certain legal decisions affecting blasting operations. The development of more rational damage criteria is thus of significant importance. Such criteria must necessarily consider the dynamic characteristics of seismic ground motions, i.e., pertinent and dominant frequency characteristics, response and Fourier spectra, etc. Very little analysis has been done with regard to determining the dynamic characteristics of blasting ground motions, however. This paper describes a research effort concerned with the determination of these characteristics for a sizeable number of actual blasting records using appropriate theoretical and computer analyses. Peak ground motion versus charge and distance relationships were derived, as well as pertinent response spectra. Statistical representations of the latter were also obtained using some 200 ground motions.