Maintaining Ductile Behavior of Steel Frame in Accidental Situation by Control the Catenary Action with Horizontal Restrains Parameters

If a building is attacked in accidental situation, professional documents assign the catenary action as the solution to maintain it, prevent the progressive collapse. In fact, the building is expected could acting in ductile behavior, going smoothly from the normal situation to fully collapse without any sudden break within. This document aims to investigate the major evolution of load carrying and deflection of a two beams over a damaged column, extracted from the real building, forming a catenary action. The beams’ behavior is investigated in order to understand the reliable circumstance of membrane effect and how the surrounded structures affect it in the accidental case. Go further, the more complexity simulation model extracted from real building, taking into account the partial restrains parameters come from the adjacent beams and columns stiffness. Each beam and/or column surround the accidental position was conversed to the analytical simplified model, then assembled together to provide a new practical formula of building robustness measurement, based on the members’ ability. In order to evaluate the real evolution in the catenary action, each parameter is specifically estimated, not only by the analytical simplify model but also using the calibration with Nonlinear Finite Element program - FINELG.