Straight and curved steel I-girder bridges - Computational Analysis and Design of Bridge Structures - page 225

Rock Creek Trail Pedestrian Bridge 2D grid model
Figure 7.29 Rock Creek Trail Pedestrian Bridge and its 2D grid model.

(a) (b)

bridge is used in this section as a demonstration for 2D grid model and 3D
finite element model.
In 2D grid model, DESCUS-I program (2011) was used in the design
phase. To establish the curved grid model, torsional constant J eq (Equation
7.5a and b, or K te in Equation 7.3) for the curved steel section and moment
of inertia I eq for the cross frame as described in Section 7.1.3 were adopted
by the program. The bridge and its grid model are shown in Figure 7.29a
and b, respectively.
A 3D finite element model of the same bridge was established by Bridge
Analysis Generator in SAP2000 (2007) (later version named CSiBridge)
without considering the vertical altitude difference and the supereleva-
tion. The concrete deck and two steel I-girders are simulated with shell
elements, and diaphragms are simulated with frame elements, as shown
in Figure 7.30. Table 7.3 lists the comparison of reactions for these two
models.

(a) Steel girders only with no deck (b) Composite steel girder with deck

Figure 7.30 3D finite element models of Rock Creek Trail Pedestrian Bridge by SAP2000.