Civil Engineering Reference
In-Depth Information
This chapter shows how to correctly represent different linear and nonlinear
regions in the stress-strain curves of the bridge components. Most of bridge
components have initial local and overall geometric imperfections as well as
residual stresses as a result of the manufacturing process. Ignoring the sim-
ulation of these initial imperfections and residual stresses would result in
poor finite element models that are unable to describe the performance of
the bridge components and the bridges as a whole. The correct simulation
of different initial geometric imperfections and residual stresses available in
the cross sections of the bridge components is addressed in this chapter. Steel
and steel-concrete composite bridges are subjected to moving live loads and
different boundary conditions, which differs from that commonly applied to
buildings. Improper simulation of the applied loads and boundary conditions
on a bridge component would not provide an accurate finite element model.
Therefore, correct simulation of different loads and boundary conditions
that are commonly associated with the bridge is the main focus of this
chapter.
5.2 CHOICE OF FINITE ELEMENT TYPES FOR STEEL
AND STEEL-CONCRETE COMPOSITE BRIDGES
To explain how to choose the best finite element type to simulate the behav-
ior of a bridge, let us look at the components of the typical steel and steel-
concrete composite bridges shown in
Figures 1.20-1.22
. We can see that
there are main bridge components comprising the structural steel members
and reinforced concrete deck slabs. On the other hand, there are also con-
necting bridge components comprising shear connectors, bolts, welds, brac-
ing members, bearings, etc. To simulate the behavior of the main and
connecting components of a bridge, we can use the different continuum,
structural, and special-purpose finite elements provided in most available
general-purpose finite element software, with ABAQUS [1.29] element
library presented as an example in this topic. General-purpose continuum
elements cover all types of solid 1D, 2D, and 3D elements, while structural
elements cover most elements used in structural engineering such as mem-
brane, truss, beam, and shell elements. Finally, special-purpose finite ele-
ments cover elements used to simulate a special connecting element such
as springs and joint elements. There are also elements used to model the
interactions and contact behavior among main and connecting bridge
components, which are mainly general contact, contact pair, and interface
elements. The aforementioned elements will be highlighted in the coming
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