This thesis deals with the comparative structural modelling and analysis of different multi-story RC frame structures for sub surface blast loads and earth quake loads. The thesis discusses the dynamic responses of two RC frame structure with different number of bays and stories that happen to blasting vibration waves generated using amount of explosion at different stand of distance and earth quake vibration waves characterized by the elastic design spectrum (Type 1 and 2) and different ground types of ES EN1998-1, 2015 scaled to different peak ground acceleration and 5% damping.rnThe RC frame structure was analyzed for sub surface blast loads using linear direct integration time history analysis method for its dynamic responses. It has been found that explosion source distance is the main influencing factor in blast loads, the larger the explosion distance the smaller is change rate of floor displacement irrespective of the height of the structure. It has also been found that a larger number of bays results in weaker blasting vibration responses.rnResponses of the RC frame structure for earth quake loads has been found using elastic response spectrum analysis. The results are compared with the responses of the structure for the blast loads and it has been found that the global responses of considered RC frame structures subjected to blast loads at nearer standoff distance and earth quake loads of 0.2g is almost comparable but at farther stands of distance, the global responses of RC frame structure for the blast loads are insignificant.