A Simplified Approach for Response Analysis of Buried Steel Pipe Subjected to Strike-Slip Faulting Actions

Buried steel pipelines crossing active fault zones are vulnerable to severe damage under strike-slip fault actions, hence proper understanding and estimation of their mechanical behavior under such geohazards is of paramount importance. This study presents a simplified semi-analytical–numerical response analysis approach for buries steel pipes making use of iterative solution method relying on the need of compatibility among the available and geometrically required pipeline deformation under the applied fault load to compute the pipe bending angle (θ). Simplified numerical analysis models capable of capturing the complex nature of the problem through the use of distributed plasticity models were used to determine the tensile strains (εT) on the pipe developing under the fault load simulated as incremental displacement. Curve fitting techniques were then used to determine the relationship between the bending angle (θ) and computed strains (εT). A series of analyses performed using the developed approach, considering three fault intersection angle (β) values (10°, 15°, and 30°) and three pipe diameter to wall thickness (D/t) ratios (58, 96, and 144) as design parameters, revealed the existence of exponential relationships between the angle θ and pipe tensile strains. Maximum strain values computed using the proposed method were lastly compared with results obtained through the solution of rigorious numerical models developed using ABAQUS FE analysis software to verify the accuracy of the method. A good overall agreement was determined to exist between the two solution approaches for all cases investigated.