ANALYTICAL METHOD FOR CHECKING THE ROBUSTNESS OF A MONOLITHIC FRAME IN AN ACCIDENTAL DESIGN SITUATION

Abstract

Currently, increasing attention is being paid to the development of analytical methods for verifying the robustness of structural systems in accidental design situations, the use of which is particularly effective at the preliminary design stage. Studies of multi-story buildings subject to sudden column removal have shown that, instead of considering the entire frame, it is entirely acceptable to discretize the design model by identifying the damaged floor for which verification calculations are performed. Unlike existing analytical approaches, which focus primarily on the flexural resistance of beams and slabs, the proposed method takes into account the additional influence of the membrane effect in monolithic slabs surrounded by beams. It is shown that taking the membrane effect into account in slabs can increase the load-bearing capacity of beam-slab floors (in some cases, by up to 30%). It was established that the membrane effect should be considered primarily when the central (inner) column is removed, whereas when the outer and corner columns are removed, it is recommended to consider only the bending effects (due to the uncertainties of providing anchorage for horizontal ties). The comparison showed good agreement between the calculation results, taking into account the membrane effect in slabs, and the experimental data obtained during tests of floor sections.