The calculation of multi-storey reinforced concrete frame building, consisting of apartments, offices and underground parking, against progressive collapse is presented in the paper. Two different ways of simulation of reinforced concrete building against progressive collapse are suggested, needed for estimation of survivability of building structures. The technique, which allows to carry out the stability of reinforced concrete structure to resist progressive collapse, is presented. This method is based on a nonlinear analysis of framed structures under the special load combination and includes dead and live loads, implying that the loading process modeling is fulfilled on the basis of the adjusted step method. The last one is of great importance for simulation of the processes in the whole life cycle of structures. The obtained results show that the offered strength calculation method of the framed structure against progressive collapse considers both geometric and material nonlinearity and also allows to assess survivability of the construction under conditions of emergency events and its stability to resist against progressive collapse. The step method of solving nonlinear problems, applied for modeling of collapse process, is shown to be more appropriate for these cases. We conclude that applying the proposed method of calculation results in more economic use of materials, giving evidence of its effectiveness.
Keywords: progressive collapse, survivability of building structures, computer simulation, structural elements, nonlinear analysis, stability, geometric and material nonlinearity, the step method