The Plastic Hinge

Abstract

The plastic hinge concept was introduced in Chapter 1 when the “hinge-by-hinge” method was applied to solve the fixed-ended beam problems. In this chapter, we shall elaborate the concept of the plastic hinge and plastic moment. The methods of computing the plastic moment and the methods of using plastic moment in the design of a cross section will be presented first. The plastic moment capacity of a section is significantly affected by factors such as axial and shear forces on the section, and the compactness of the section. The effects of these factors on the plastic moment capacity of a section will then be described. Since the strength of a connection of a given member to the adjoining members may govern the ultimate moment-carrying capacity of the member, methods of estimating the strength of a given connection and methods of designing the connection under a given loading will be presented in the later part of this chapter.