Mechanism leading to rotation of neighboring hinges in contradictory directions structure
Plastic pivots or hinges are formed because of bending or twisting in a configuration member at which an infinite rotary motion can occur at a stable Plastic Moment at that given section. So long as there are a number of positions of “local†utmost bending/twisting moment alongside the portal frame or beam there are a number of points of “local†greatest Bending Moment along the beam, the first Plastic Hinge will be generated at the numerical greatest point provided working load stipulations are still under operation(Gere & Timoshenko 1990, p. 328). If additional Plastic Hinges are needed for cave-in or collapse of the frame, then it will take place at the subsequent lesser value selected from the remaining neighboring maxima. As soon as adequate plastic hinges have been generated to switch the structure/arrangement into a mechanism then the collapse of the entire structure will take place. The actual number of Plastic hinges required for breakdown does not change for a specific structure depending on the set loading circumstance, even though a section of the beam may collapse separately by the generation of a slight number of hinges. The structure acts like a hinged mechanism leading to rotation of neighboring hinges in contradictory directions structure. In short, the collapse or ultimate weight/load is achieved when a mechanism is produced. The actual number of plastic pivots generated due to weight applied on the frame or any beam should be just enough to create a mechanism (Gere & Timoshenko 1990, p. 340).
