Joint-level response of buried segmented ductile iron pipelines under strike-slip faulting

Abstract This study investigates the seismic response of ductile iron (DI) jointed buried pipelines under lateral strike-slip surface faulting through finite element simulations with varying fault geometries and soil conditions. Both tension- and compression-inducing fault scenarios were analysed, focusing on joint-level mechanisms, including axial pullout, interlocking behaviour, rotation and localized stress development as a function of fault crossing angle ( $$\:\beta\:$$ ), fault crossing position (pipe centered (PC), and joint-centered (JC)), and soil type. For tension-induced faults, pullout failure was primarily controlled by $$\:\beta\:$$ , fault crossing position, and the joint expansion limit ( $$\:{U}_{crit}$$ ), with pipelines accommodating greater displacement when faults were nearly perpendicular (β ≈ 90°) or intersected joint centres ( $$\:JC$$ ), while narrower angles ( $$\:\beta\:$$ = 45°) induced higher axial demands and premature pullout. Joint interlocking effectively limited relative axial movement and localized stresses, and maximum joint rotations often exceeded manufacturer limits. In compression scenarios, spigot elements experienced localized crushing at the material’s ultimate stress (460 MPa), with no pullout observed, while stress propagated through joint “binding zones” in wave-like patterns, particularly for $$\:\beta\:\:$$ = 67.5°, and narrower angles produced more uniform stress but earlier failure. Soil type had a secondary influence, with fault geometry governing performance. Overall, the most favourable configuration was observed for $$\:\beta\:$$ = 90°, JC case in medium dense sand, whereas $$\:\beta\:$$ = 45° cases exhibited the earliest and most extensive failures. These findings highlight the critical role of fault alignment, joint interlocking, and axial displacement capacity in enhancing the seismic resilience of segmented buried pipelines.