Inelastic Response of Structures

Abstract

The conventional design approach works with factored loads and reduced material capacities such as strength. When subjected to service loads, the structure is detailed such that it behaves elastically. For extreme loadings, the structure is allowed to experience a limited amount of deformation beyond the elastic limit. This deformation is called “inelastic” since in contrast to elastic deformation, when the loading is removed, the structure does not return to its original position. Up to this point in the text, we have assumed the behavior to be elastic. In Chap. 10, we included geometric nonlinear effects but still assumed elastic behavior. Here, we introduce an additional effect, inelastic behavior. We start with an in-depth discussion of the stress–strain behavior of structural steels and concrete, apply these ideas to beams subjected to inelastic bending, and then develop an analysis procedure to determine the inelastic response of frame-type structures. This approach allows one to estimate the “maximum” loading that a structure can support, i.e., the “limit load.” Examples illustrating the influence of inelastic behavior on the ultimate capacity are included.