Seismic Response of Horizontally Bent Buried Pipelines Under Strike-Slip Faulting: A Parametric Study Using BNWF Modeling

Buried continuous pipelines are vulnerable to seismic hazards, particularly near fault crossings where fault-induced ground displacement can cause significant structural damage. Although design standards typically recommend against placing bends near fault zones, practical constraints often necessitate their presence. This study employs a beam on nonlinear Winkler foundation (BNWF) numerical modeling approach to investigate the seismic response of horizontally bent buried continuous steel pipelines subjected to strike-slip faulting. Key parameters including pipe bend angle, pipe burial depth, and fault crossing distance from the bend are systematically varied. The pipeline response is evaluated in terms of maximum shear force, maximum bending moment, and overall strain. Results reveal that bends significantly amplify shear forces (up to 120% increase) and bending moments (up to 36%) compared to straight pipelines, with pronounced sensitivity when bends are provided at/near the fault zone. These findings quantitatively underscore the critical role of bend geometry and fault proximity in pipeline seismic design, providing actionable insights to improve resilience in seismic-prone regions.