Nonlinear Material Behavior of the Bridge Components - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 100

Earlier investigations by Ansourian [ 2.72 ] used the finite element
method in analyzing composite steel-solid slab floor systems. The author
studied the full composite action between concrete slabs and steel joists in
the elastic range. The principal variable of the study was the ratio of the flex-
ural stiffness of the joist and slab. Two different methods of finite element
models were investigated. In the first model, the slab was represented by
a combination of 16-node and 8-node solid 3D prismatic elements and
the joist was represented by plane stress elements. At a section of the struc-
ture, each steel beam flange was represented by one element and the web was
represented by two elements. The authors found satisfactory convergence
with this method, but the preparation of data and analysis of output were
time-consuming. In the second model, the slab was represented by thin plate
elements built up from the superposition of linear curvature triangles for the
flexural stresses and linear strain triangles for the membrane stresses, and the
joist was represented by beam elements. The author found that the second
model gives applicable output of bending moments and plane stresses.
Mofatt and Dowling [ 2.73 ] introduced a finite element study of the elastic
longitudinal bending behavior of composite box girder bridges in which the
use of flexible shear connectors results in incomplete interaction between
the slab and girder components. The buckling and the inelastic behavior
were not considered. Some preliminary investigations were carried out to
determine suitable finite element meshes for use in analyzing the girders.
The box girders, the slab, and the reinforcement were represented by shell
elements. The shear connectors were represented by linkage elements that
allowed slip in the plane of the concrete-steel interface. It was assumed that
the shear connection would be provided by 19 mm 100 mm headed studs.
On the basis of information given in reference [ 2.74 ], the authors used con-
stant slip modulus of the studs as 0.4 10 6 N/mm. The authors highlighted
the need for codes of practice to include design information on the stiffness
and distribution requirements of the connectors in composite girders.
Mistakidis et al. [ 2.75 ] introduced a numerical method taking into con-
sideration the nonlinearities introduced in the analysis of long-span compos-
ite girders. The authors showed that the experimental data show a nonlinear
behavior for the load-deformation curve of the shear connectors joining the
steel beam with the concrete slab. The influence of the behavior of the con-
nectors has been demonstrated through the analysis of a long-span composite
girder spanning 30.0 m. The finite element method was used in modeling
the composite girder. Bending finite elements with axial deformation pos-
sibility representing the concrete slab and the steel beam were used. Spring