Effect of support condition on the mechanical behavior of ductile iron pipes buried at shallow depth within the backfill of controlled low strength material

•Ductile iron pipes buried at shallow depth backfilled with controlled low strength materials are tested plausible.•Two support conditions are simulated: (1) sitting directly on a stiff surface such as a culvert; (2) no support underneath the trench such as the soil is lost due to water leakage.•Strength of backfill material has noticeable influence on pipe behavior.•Support condition has significant effect on pipe stress and backfill material cracking behavior.