Load Reduction Factors for Buried Clay Pipes

Abstract

Current ASTM installation design of vitrified clay pipes involves the determination of backfill loads and load factors. Trench backfill loads are commonly computed using the Marston load theory, which is conservative because it ignores the load‐bearing capacity of sidefill and the existence of lateral earth pressures. The load factors used were originally determined experimentally. Due to the great variability in the soils and installation methods, the held data available for determining the load factors are limited. Finite element analyses were performed to investigate the backfill loads and the distribution of earth pressures around buried vitrified clay pipes under various trench bedding conditions. The load reduction factors were calculated as the ratio of the Marston load to the finite element load. The results showed that the load reduction factor is affected by the backfill height, the pipe diameter, and the trench width.