TM 5-820-3/AFM 88-5, Chap. 3
10-inch-thick reinforced concrete slab with inserted
be used to provide egress for the storm runoff. The
lightweight circular pipes used for the grating
design may also be used to repair existing box
openings. While only 4-inch-diameter holes have
drains which have failed.
been indicated in the figure, additional holes may
. Inlet drainage structures, particularly box
deteriorate. help Construction specifications
drains, have been known to settle at rates different
requiring careful backfilling around inlets will help
from the adjacent pavement causing depressions
prevent the differential settling rates.
which permit pavement failure should the subgrade