Reinforced concrete bridges - Computational Analysis and Design of Bridge Structures - page 110

y

y

x x δ

x 1 x 1 δ 1

y

y

x

x

δ

x 1 x 1

δ 1

δ < δ 1

Figure 4.7 Deflection profile of a nonskewed deck.

and width-to-span ratio. The load is first transferred from the strip to the
support over a defined length along the support line from the obtuse-angled
corners. Later the force gets redistributed for full length. The force flow
is shown in Figure 4.8a and b where the thin lines in Figure 4.8a indicate
deformation shape. The distribution of reaction forces along the length of
the supports is shown on both the support sides.
For skewed bridges, the deflection of the slab is not uniform or sym-
metrical as in the case of nonskewed deck. There will be warping that
leads to higher deflection near obtuse-angled corner areas and less deflec-
tion near acute-angled corner areas. For small skew angles, both free edges
will have downward deflection but differing in magnitude. For large skew
angles, the maximum deflection is near the obtuse-angled corners. Near
the acute-angled corner, there could be even negative deflection resulting
in S-shaped deflection curve with associated twist. Increase in skew angle
decreases bending moments but increases twisting moments (Rajagopalan
2006).
The characteristic differences between the behavioral aspects of a skewed
deck and a nonskewed deck are as follows (Rajagopalan 2006):

• High reaction at obtuse corners.
• Possible uplift at acute corners, especially in the case of slab with very
high skew angles.