the cost of pipe failures in sewerage and water supply pipelines in england and wales is estimated at about 40 m per annum, (1975 prices). in the various instances of pipe failure investigated by trrl rigid pipes of up to 300 mm diameter seldom seem to fail by crushing unless subjected to localized high loading from traffic or large inclusions in backfill or bedding. beam fracture is more common. existing british standards for clay and concrete pipes contain tests to measure the crushing strength but not the bending moment resistance (bmr). a recognised bmr test therefore seems necessary. this report describes a practical test for the measurement of bmr based on using a standard testing machine adapted to apply a four point loading system to 100 mm, 150 mm, 225 mm diameter clay and 225 mm, 300 mm, 375 mm diameter concrete pipes. from the ultimate loads obtained from a series of bmr and british standard crushing tests, the ultimate stresses were calculated. it was found from a comparison of these ultimate stresses that the pipes were not isotropic. it was also found that there was little or no significant correlation between the bmr and crushing strengths of clay or concrete pipes.(a)

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