Although it is not practical to design buildings to withstand explosive loads, it is possible to improve the performance of structures in resisting blast induced progressive collapse. By determining the critical standoff distance and hardening key elements (columns), Designers can enhance the life safety of the persons within the building and facilitate rescue efforts during such an event. In this Book it is tried to investigate the dynamic response and damage of RC framed structure under external blast loading using recommended procedures and code provisions. Blast analysis was performed based on sequences of nonlinear analysis using SAP2000 and SDOF approximation technique at different standoff distances.