Finite Element Analysis of Steel and Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 496

components comprising the headed studs, surrounding concrete, steel beam,
and interfaces among the aforementioned components. In this case, the
finite element mesh will be simulating the shear connection behavior and
the finite element model developed can be used to predict the local behavior
of the shear connection. The finite element model in this case can evaluate
the shear connection capacity, failure mode, and load-slip characteristic of
the headed stud. This has been reported previously by the author in
[2.68, 2.69]. However, if we model full-scale composite girders with solid
slabs having numerous headed stud shear connectors, then the finite element
mesh used to model the local shear connection behavior will not be used.
This is attributed to the fact that including all the details of every connection
around every headed stud will result in a huge finite element mesh for the
composite girder that may be impossible to be analyzed. In this case, we can
incorporate the local behavior of the headed stud in a shear connection to
the overall composite beam behavior using springs or JOINTC elements. In
this case, we can study the overall behavior of the composite beam using the
developed finite element model. In this case, the finite element mesh of the
composite girder will be reasonable in size, and the finite element model can
evaluate the moment resistance of the composite beam, load-displacement
relationships, failure modes, etc. This was also previously reported by the
author in [2.68, 5.2 ] . Using the same approach, we can develop a finite ele-
ment mesh to study the whole bridge behavior, and in parallel, we can
develop other local finite element models to study the behavior of the indi-
vidual components and incorporate them in the whole bridge model. In this
book, Chapters 6 and 7 will include finite element models developed for the
individual bridge components as well as for the whole bridges.
Structural steel members have flat and curved regions. Therefore, the
finite element mesh of the individual members has to cover both flat and
curved regions. Also, most structural steel members have short dimensions,
which are commonly the lateral dimensions of the cross section, and long
dimensions, which are the longitudinal axial dimension of the structural
member that defines the structural member length. Therefore, the finite ele-
ment mesh has to cover both lateral and longitudinal regions of the structural
steel member. To mesh the structural steel member correctly using shell ele-
ments, we have to start with a short dimension for the chosen shell element
and decide the best aspect ratio . The aspect ratio is defined as the ratio of the
longest dimension to the shortest dimension of a quadrilateral finite element.
As the aspect ratio is increased, the accuracy of the results is decreased. The
aspect ratio should be kept approximately constant for all finite element