ABSTRACT
The peak particle velocity (PPV) of ground motion and the associated predominant frequency are used the most commonly as the safety criteria against the damaging potential of blast vibrations. However, the PPV is not equally effective for producing damages in all the structures with different dynamic characteristics; viz., natural frequency and damping ratio. The various frequency-dependent safety criteria in terms of PPV are applicable to specific class of structures and the blast characteristics. For example, frequency-dependent safety criteria due to Siskind et al. (1980) is based on the observations on one and two storey structures subjected to mining blasts. These are thus not appropriate for other type of structures with different dynamic characteristics subjected to construction blasts with quite different frequency and amplitude ranges. The more generalized safety criteria of much wider applicability are thus required to be formulated directly in terms of the peak structural response to the blast vibrations. To estimate the safe charge weight per delay for blasting at a given distance, it is then necessary to have a predictive model for the peak structural response in terms of the maximum charge weight per delay and the distance. To this end, an empirical model has been developed to estimate the response spectral amplitudes of blast vibrations, because the response of most structures can well be approximated by its fundamental mode.
