Performance-based assessment of protection measures for buried pipes at strike-slip fault crossings

Onshore buried steel pipelines are vulnerable to fault rupture, where large ground displacements are imposed on the crossing pipe and thus protection measures are often necessary to avoid failure. A three-step methodology based on the framework of performance-based earthquake engineering is presented on assessing the effectiveness of protection measures against the consequences of strike-slip faulting on pipes. Firstly, the randomness of the fault movement is quantified, next the pipeline mechanical behavior is numerically assessed and finally the results are combined to extract the strain hazard curves, which are easy-to-handle engineering decision making tools. The various protection measures used in engineering practice or proposed in the literature are evaluated through the mean annual rate of exceeding strain values, also including a simple safety checking format at the strain level. Conclusions are extracted from the proposed assessment methodology on the efficiency of measures with reference to engineering practice and safety requirements of the pipeline operator.