Protecting abutments and piers at bridges is beneficial in limiting the effects of scour. Use flexible armoring (i.e. stone protection) for wet crossing structures. Concrete riprap, due to its rigidity, masks problems. Consequently, voids can form under them and eventually undermine the pavement or approach slab. Guidance on the use of stone and sizing and thickness to specify can be found in Chapter 11 of the .

In the plans Stone Protection should be specified and called out as follows (on each abutment side or location of placement):

Riprap (Stone Protection) XX in.

(where XX is the size in inches)

Thickness = YY in.

(where YY is the appropriate thickness)