An empirical model for determining of safety radius against air-blast in demolition operation of concrete structures

One of the new engineering techniques in the world is demolition by controlled blasting operation. The method contains some mining and civil engineering’s techniques. They are the controlled blasting, proper selection of type and amount of explosives, air-blast, ground vibrations and fly rock effects and structure analysis, construction material properties, like mechanical strength of them. This paper has subjected to control of air-blast in concrete structures. Sometimes intensity of air-blast can due to fragment of windows and weak members of structures in faraway, if there are strong winds and inversion. It is clear that control of air-blast is very important; therefore four standards (USA, UK, Australia & Spain) for determining of allowable sound levels have collected in the paper. Authors made 22 concrete columns and three blast holes were drilled in each column. The hole spacings have selected independently. It means that blast of a hole does not affect the on other holes. After each blasting, sound level in dB (A), distance and amount of explosives in each period have recorded. Finally, the data were converted to logarithmical form and analyzed by multiple regressions and was obtained an empirical model. Correlation coefficient of the model shows that the model’s results are good agreement with empirical data. The model can evaluates safety radius against to airblast in demolition operation of concrete structures.