In modern design practice, a numerical method for verifying the robustness of damaged structural systems based on imitation modeling is becoming increasingly common. This method utilizes the fundamental principles of macromodeling, according to which the elastic behavior of a structural system is determined by the operation of linearly elastic rods and plates, while nonlinear behavior is completely determined by the behavior of point and/or linear plastic hinges. Thus, an adequate description of the diagrams for plastic hinges is an important element of modeling. This article presents proposals for describing the parametric points of plastic hinges for bending, shear, and axial tension, which allows for describing the operation of a damaged structural system at all stages of its operation. It is proposed to limit the maximum rotation angles during bending, taking into account the shear failure criterion. The calculation results obtained using an imitation finite element model are compared with experimental data.
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.
A. Tur· Herald of Polotsk State Univ...· 0 citations