Vol.21, No.3, 2021, pp. 245–253
UDC:

After events such as explosion, formidable earthquake, etc., main columns and bearing elements of a building may be destroyed in some parts and if remaining structure does not have adequate resistance for bearing vertical loads, then a progressive collapse initiates and even fully destroys the building in the worst circumstances. In this study, structures are investigated in two states. First state includes 4 floor structures with plans for 4 spans of 6 m, 6 spans of 4 m, and 3 spans of 8 m that are 3D evaluated and analysed. In the second state, each investigated model is evaluated and analysed in 5 states with various compressive strength. Comparison of frame behaviour indicates that structural capacity reduces by increasing structure plan dimensions. By contemplation in produced results, it is demonstrated that four floor frames with 6 spans of 4 m almost have similar capacities. Structural exceedance probability will also enhance from each performance limit state CP, IO, and LS (collapse prevention, immediate occupancy, and life-safety) by increasing the length of span in a determined and constant spectral acceleration.

Keywords: progressive collapse, uncertainty parameters, yield limit states, structure capacity