Examples of Finite Element Models of Steel-Concrete Composite Bridges - Finite Element Analysis and Design of Steel and Steel-Concrete Composite Bridges - page 619

shown in Figure 7.1 , of Grade 60 having a yield stress of 413 MPa (60 ksi).
The reinforcement bars were spaced at 203 mm longitudinally and trans-
versely. The top and bottom reinforcement bars had a cover of 44 mm.
The shear connectors were headed studs having a diameter of 19 mm and
a height of 114 mm. Eighty pairs of headed studs were used in the composite
plate girder G1 as shown in Figure 7.1 . The composite plate girders were
subjected to a single concentrated load applied at midspan via a spreader
beam. The loading was applied in increments using displacement control.
The composite plate girder tested by Mans [ 7.29 ] was modeled in this
book using ABAQUS [1.29]. In order to obtain accurate results from the
finite element analysis, all the composite plate girder components must
be properly modeled. The composite plate girder components comprise
the steel plate girder, concrete slab, headed stud, and reinforcement bars.
The finite element analysis has accounted for the nonlinear material pro-
perties and geometry of the components as well as the interfaces between
the components that allowed the contact and bond behavior to be modeled
and the different components to retain its profile during the deformation of
the composite plate girder. The steel-concrete composite plate girder com-
ponents were modeled using 3-D solid elements (C3D8) available in the
ABAQUS [1.29] element library. The elements have three degrees of free-
dom per node and suit all the strengthened composite girders since lateral
torsional buckling of the steel beam compression flange is limited by the sur-
rounding concrete slab properly connected to the top flange via headed stud
shear connectors. Only half of the composite plate girder was modeled due
to symmetry as shown in Figure 7.2 . The total number of elements used in
the model was 7958 elements. Different mesh sizes were tried to choose the
reasonable mesh that provides both reliable results and less computational
time. All the nodes in the middle symmetry surface were prevented to dis-
place in direction 2-2. The roller support nodes were prevented to displace
in direction 3-3 only. The load was applied in increments as concentrated
static loads at midspan, which is identical to the experimental investigation
[ 7.29 ] . The nonlinear geometry was included to deal with the large displace-
ment analysis.
The shear forces across the steel plate girder-concrete slab interface of G1
test [ 7.29 ] are transferred by the mechanical action of headed stud shear con-
nectors. The load-slip characteristic of headed stud is of great importance in
modeling the shear interaction between steel plate girder and concrete slab.
The region around the stud is a region of severe and complex stresses. The
load-slip characteristic of headed stud depends on many factors including