What is the consideration in selecting the orientation of wing walls in the design of bridge abutments?
There are three common arrangements of wing walls in bridge abutments based on Dr. Edmund C Hambly (1979):
(i) Wing walls parallel to abutments
This is the simplest and shortest time to build but is not the most economical design. This design has the advantage that it has least disturbance to existing slope embankment.
(ii) Wing walls at an angle to abutments
This is the most economical design among the three options in terms of material cost.
(iii) Wing walls perpendicular to abutments
Though it is not the most economical design, the wing walls provide a continuous alignment with bridge decks which provide supports to parapets. However, they cause disturbances to adjacent structures and utility services during construction. Moreover, if the bridge is curved, the wing walls may hinder the road curvature.
One the other hand, when the wing walls are structurally connected to the abutment, then structural advantage can be taken by the stability of box structure.