During their service life, modern structures may experience extreme loading conditions. Large loads generated from bomb explosion may have catastrophic consequences with a large number of casualties as well as great economical loss. Ever since the terrorist attack of 2001, great safety concerns have been raised for urban areas where more and more high-rise buildings have been erected and thus are more prone to suffer the potential threat. Among all the structural responses to blast loads, the catastrophic progressive collapse has attracted great attention around the world. Experimental studies on this topic are not only expensive but also are often prohibited due to safety concerns. With the advancement of computational mechanics techniques and computer power, reliable computer simulations of structural response and collapse to blast loads become possible. However, even with modern computer power, such computer simulations are still extremely time and resource consuming. In this paper, a new numerical approach that incorporates static condensation into the FE model is presented to simulate blast load induced structural response and progressive collapse. Two 6-story RC frame buildings are used as examples to demonstrate the efficiency of the proposed method. For comparison, direct finite element modeling of the same example frame structure is also carried out. Comparing the results from both approaches, it is found that the proposed method is efficient and reliable in simulating the structural response and progressive collapse with substantially less computational effort as compared to the direct FE model simulations. © 2013 Elsevier Ltd.