Concrete Pipe Culvert Behavior—Part 1

An 84-in. (2.14-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; and (6) positive projection, line bearing on hard earth. Qualitative observations were made of progressive changes in cracking patterns, and measurements were made of pipe shape in each zone at intervals of fill height. Results indicated that placement of a pipe in a trench was of much greater importance than shaping the bedding. The 60° concrete bedding failed most dramatically. The polystyrene plank bedding showed some promise.