Robustness of reinforced concrete structural systems under accidental actions

Moscow State University of Civil Engineering, Reinforced Concrete and Masonry Structures Department, 129337, Moscow, 26 Yaloslavskoe shosse, Russia

^* Corresponding author: savinsyu@mgsu.ru

Abstract

The purpose of this study was to create computational models and criteria for assessing the robustness of reinforced concrete frames of multi-storey buildings in case of stability failure of their elements under accidental actions accounting for the mode of loading and energy dissipation. Experimental studies of deformation and fracture of reinforced concrete frames under an accidental impact allowed to identify, depending on the design solutions, two characteristic failure mechanisms: due to the loss of cross-sectional strength for frames of the first and second types with the slenderness of the columns of 4.8; due to the loss of stability for the frame of the third type with the slenderness of the columns of 22. Application of the theory of structural stability and dynamics allowed to construct a multi-level design model and an algorithm for assessing the stability of physically and structurally nonlinear frames. The study formulates and substantiates the criteria of stability failure of the eccentrically compressed elements and the structural system as a whole under an accidental action. As such criteria the following ones are considered: equality to zero of the increment of deformation energy of the system or achievement of zero tangent stiffness of its elements.