Assessment of structure damage to blasting induced ground motions

Empirical allowable vibration levels for surface structures generated by underground explosions are usually given in terms of peak ground particle velocities. Those allowable vibration criteria do not take the structural type, site conditions and ground vibration frequency contents into consideration. This paper performs a damage assessment of surface structures subjected to ground stress wave excitation on the basis of a nonlinear dynamic analysis of structures. The ground excitations are generated numerically by a commercial software autodyn. The validity of the numerical simulated ground motions is proved by comparing the attenuation law of their peak particle velocities (PPV) with those obtained independently in field tests. A damage index defined in earthquake engineering, based on a linear combination of the maximum deformation (ductility) and the hysteretic energy dissipation (loading history), is used. A parametric study of the effects of structural type, charge distance, site conditions, as well as the explosion conditions is performed by using three typical reinforced concrete (RC) structural models designed on the basis of British Standard 8110. A safe inhabitant distance for surface structures is estimated and results are compared with those obtained on the basis of empirical allowable vibration criteria.