Progressive Collapse of Existing RС Structures due to Environmental Effects: A Numerical Approach for Strengthening by Ties

Abstract

Existing old reinforced concrete (RC) buildings are sometimes subjected to obligatory removal of some structural element‐members, e.g. columns, and so to the risk of a progressive collapse. This happens due to various reasons, which can concern changes of serviceability and requirements, or environmental effects which cause strength degradation etc. In order to avoid such a progressive collapse, a modification of the structural response and a redistribution of internal actions can result to a requirement for strengthening the remaining structure after the removal of the degraded elements. The present study deals with such a case, which concerns the computational analysis of framed RC structures under the removal of some columns and the so‐induced requirement of a strengthening by ties (tension only elements). The unilateral behaviour of these cable‐ties, which can undertake only tension, is strictly considered, and the response of the remaining historic structure strengthened by ties is computed. Finally, in a practical case of a framed RC structure, the effectiveness of the proposed methodology is shown.