Straight and curved steel box girder bridges - Computational Analysis and Design of Bridge Structures - page 254

8.4.2 curved box beam model (M4)
In this model, Beam 188 is also used to model the curved box girder. The
model is similar to that of the straight box except the curvature. Similar
to the straight box beam model, Beam 4 (with a hinge at an end or a truss
element) is used at supports to model boundary conditions. Two cases
regarding boundary conditions are modeled: (1) Two bearings are pro-
vided at all supports and (2) two bearings are provided at the middle sup-
port (at pier) and single bearing is provided at end supports. Figure 8.20
shows the bending moment diagram throughout the span.
The stability of the single box girder under the maximum overturn-
ing combination of DLs, wind load, and live load with its centrifugal
effects is also analyzed. Figure 8.21 shows the reaction forces where the
insertion shows the twin-bearing intermediate support at the pier loca-
tion. The maximum bearing conditions under various load combinations
are checked. The beam element shown in solid circle in the insertion of
Figure 8.21 representing the shear center is connected with rigid links
supported by two hinges at bearings. Tables 8.4 through 8.6 compare beam
and shell models for curved box girder bridges. Tables 8.4 and 8.5 compare
support reactions, moments, and bending stresses for 2D and 3D models.

Line stress

y

x

z

−0.753E+08 −0.254E+08 0.244E+08 0.742E+08 0.124E+09

−0.504E+08 −538393 0.493E+08 0.991E+08 0.149E+09

Figure 8.20 Bending moment diagram.