Nonlinear Material Behavior of the Bridge Components - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 47

CHAPTER 2
Nonlinear Material Behavior
of the Bridge Components
2.1 GENERAL REMARKS
Chapter 1 has provided a brief background on steel and steel-concrete com-
posite bridges and reviewed recent developments reported in the literature
related to the design and finite element modeling of the bridges. This chapter
highlights the nonlinear material behavior of the main components of steel
and steel-concrete composite bridges, comprising structural steel, concrete,
reinforcement bars, shear connectors, bolts, and welds. Overall, this chapter
aims to provide a useful background regarding the stress-strain curves of the
different materials used in the bridges. Also, this chapter aims to highlight the
important parameters required for finite element modeling. The definitions
of yield stresses, ultimate stresses, maximum strains at failure, initial stiffness,
and proportional limit stresses are presented in this chapter. This chapter
enables beginners to understand the fundamental behavior of the materials
in order to correctly insert them in the finite element analyses. Covering the
behavior of shear connectors in this chapter is also important to understand
how the shear forces are transmitted at the steel-concrete slab interfaces in
composite bridges. In addition, the material properties of the main compo-
nents of joints used in steel and steel-concrete composite bridges such as
bolts are highlighted in this chapter. Furthermore, this chapter presents
how the different materials are treated in current codes of practice and
the design values specified in current codes of practice. This chapter paves
the way for Chapters 3 and 4 , which address the design and stability issues
related to steel and steel-concrete composite bridges. It should be noted that
bridge components, such as structural steels, concrete, and reinforcement
steels, are used in bridge and building constructions. However, when pre-
senting the material behavior of a component in this chapter, it is presented
as it is used in bridges. As an example, structural steels used in bridges gen-
erally have more rigid performance requirements compared with steels used
in buildings. Bridge steels have to perform in an outdoor environment with
relatively large temperature changes, are subjected to excessive cyclic live
loading, and are often exposed to corrosive environments. In addition, steels