Ductility Requirement In Progressive Collapse Resistance Of Non-seismic Frame Structures

Currently, the progressive collapse of the structures has become a serious threat to public safety. There are more and more structure progressive collapse caused by unexpected incidents as terrorist attack, fire, hurricane, constructional deficiency, human error and gas explosion. Since the partial collapse of the Ronan Point apartment building in 1968, engineers and reaserchers begin to pay more attention to the prevention of progressive collapse.Many design codes and methods for preventing progressive collapse have been developed, including the Tie Force and Alternate Load Path methods. However, researches on progressive collapse in our country are still insufficient. Until now, the codes criteria about the resistance of progressive collapse had not been provided. It is important to study the ductility of structures, for it is a major facor for preventing the progressive collapse.In this paper we reviewed the state of progressive collapse prevention home and abroad, and summaried the relevant design specifications for structure progressive collapse resistance. Based on the stress-strain relationship of steel and concrete and basic assumptions in designing code for concrete structures in our country, calculation formula of section yield curvature, section ultimate curvature and plastic rotation are deduced. The software ANSYS is used to analyze a RC model frame structure in a progressive collapse experiment.The analysis includes linear static procedure and nonlinear static procedure.The results prove the effectiveness of the programme. Some questions about ANSYS simulation are discussed. Then a performance evaluation of structure processive collapse resistance, based on the design procedure prescribed in GSA, is applied to an eight-story typical frame of none sesmic design. The frame is designed according to the current China desigining codes. Four different cases are considerd. In each cases, one column in particular location is removed These columns are the middle column of the long side of the building, the middle column of the short side of the building, the corner column and the internal column repectively.Addtionally, the requirement for plastic rotational capability to resist progressive collapse is analyzed. Strategies and measures to ensure a ductile structure of none sesmic design are proposed. Finally, the conclusions of this paper are summarized and the prospect of further studies is discussed.