ABSTRACT
An elastic analysis of a structure is important to study its performance, especially with regard to serviceability, under the service loading for which the structure is designed. However, if the load is increased until yielding occurs at some locations, the structure undergoes elastic-plastic deformations and, on further increase, a fully plastic condition is reached, at which a sufficient number of plastic hinges are formed to transform the structure into a mechanism. This mechanism would collapse under any additional loading. A study of the mechanism of failure and the knowledge of the magnitude of the collapse load are necessary to determine the load factor in analysis. Alternatively, if the load factor is specified, the structure can be designed so that its collapse load is equal to, or higher than, the product of the load factor and the service loading.
