Ground vibrations due to blasting were monitored at two construction projects and analysed for peak particle velocity(PPV) and frequency. Attenuation equations were determined for both the sites and used to estimate the vibration level. The dominant frequency Varied from 11 to 53 Hz, which was higher than those of mining blasts. The frequency was same whether blasts were conducted with or without delays and there was no significant relation between the frequency of construction blasts with the maximum charge per delay or the distance. For all construction projects, which are conducted close to surface structures, ground vibrations should be monitored and analysed. Depending on the type of structures and the frequency, permissible levels of ground vibration can be determined from the DGMS Circular. For structures not mentioned in this circular, permissible vibration level can be decided in consultation with a specialist.
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