E01F—ADDITIONAL WORK, SUCH AS EQUIPPING ROADS OR THE CONSTRUCTION OF PLATFORMS, HELICOPTER LANDING STAGES, SIGNS, SNOW FENCES, OR THE LIKE
E01F5/00—Draining the sub-base, i.e. subgrade or ground-work, e.g. embankment of roads or of the ballastway of railways or draining-off road surface or ballastway drainage by trenches, culverts, or conduits or other specially adapted means
E01F5/005—Culverts ; Head-structures for culverts, or for drainage-conduit outlets in slopes