Concrete Pipe Culvert Behavior—Part 2

An 84-in. (2.13 m)-diam., reinforced concrete, dummy pipe culvert, with a 1,000-D load rating, was buried under 136 ft (41.5 m) of highway embankment. Six 40-ft (12.2-m)-long zones were subjected to the following bedding and backfill parameters: (1) pipe in trench, shaped bedding; (2) pipe in trench, unshaped, fine aggregate bedding; (3) positive projection, shaped bedding; (4) positive projection, 60° concrete bedding; (5) positive projection, pipe bedded on two 3 in. x 24 in. (7.6 cm x 61.0 cm) polystyrene planks; (6) positive projection, line bearing on hard earth. Soil stresses acting at the periphery and displacements at the intrados were measured in each zone at intervals of embankment depth. Revisions recommended for California culvert design specifications include the use of 2 bands of loading, with the actual embankment density acting vertically, and 30% and 100% of that density acting laterally.