Summary Buried pipelines are often constructed in seismic and other geohazard areas, where severe ground deformations may induce severe strains in the pipeline. Calculation of those strains is essential for assessing pipeline integrity, and therefore, the development of efficient models accounting for soil‐pipe interaction is required. The present paper is aiming at developing efficient tools for calculating ground‐induced deformation on buried pipelines, often triggered by earthquake action, in the form of fault rupture, liquefaction‐induced lateral spreading, soil subsidence, or landslide. Soil‐pipe interaction is investigated by using advanced numerical tools, which employ solid elements for the soil, shell elements for the pipe, and account for soil‐pipe interaction, supported by large‐scale experiments. Soil‐pipe interaction in axial and transverse directions is evaluated first, using results from special‐purpose experiments and finite element simulations. The comparison between experimental and numerical results offers valuable information on key material parameters, necessary for accurate simulation of soil‐pipe interaction. Furthermore, reference is made to relevant provisions of design recommendations. Using the finite element models, calibrated from these experiments, pipeline performance at seismic‐fault crossings is analyzed, emphasizing on soil‐pipe interaction effects in the axial direction. The second part refers to full‐scale experiments, performed on a unique testing device. These experiments are modeled with the finite element tools to verify their efficiency in simulating soil‐pipe response under landslide or strike‐slip fault movement. The large‐scale experimental results compare very well with the numerical predictions, verifying the capability of the finite element models for accurate prediction of pipeline response under permanent earthquake‐induced ground deformations.

Hydrocarbon pipelines constructed in geohazards areas, are subjected to ground-induced actions, associated with the development of severe strains in the pipeline and constitute major threats for their structural integrity. In the course of pipeline design, calculation of those strains is necessary for safeguarding pipeline integrity, and the development of reliable analytical/numerical design tools that account for soil-pipe interaction is required. In the present paper, soil-pipe interaction models for buried steel pipelines subjected to severe ground-induced actions are presented. First, two numerical methodologies, (simplified and rigorous) and one analytical are presented and compared, followed by an experimental verification; transversal soil-pipe interaction is examined through full-scale experimental testing, and comparisons of numerical simulations with rigorous finite element models are reported. Furthermore, the rigorous model is compared with the results from a special-purpose full-scale “landslide/fault” experimental test in order to examine the soil-pipe interaction in a complex loading conditions. Finally, the verified rigorous model is compared with both the simplified models and the analytical methodology.

In geohazard areas, buried pipelines are subjected to permanent ground-induced deformations, which constitute major threats for their structural safety. Geohazards include seismic fault movement, liquefaction-induced lateral spreading, slope instability or soil subsidence, and are associated with the development of severe strains in the pipeline. Calculation of these strains is necessary for assessing pipeline integrity. In the present paper, an analytical methodology is presented that allows for simple and efficient pipeline strain analysis in geohazard areas. The methodology is compared with existing more elaborate analytical methodologies and finite element predictions. The analytical formulation results in closed form expressions and the model contributes to better understanding of buried pipeline behavior subjected to permanent ground-induced deformations. The proposed methodology is directly applicable to fault actions, but it can be also applicable to a wide range of geohazards. Furthermore, using this methodology, one may predict the strains developed in the pipeline wall due to ground-induced actions in a simple and efficiently manner and is suitable for the preliminary design of pipelines.

The present paper offers an overview of available methodologies and provisions for the structural analysis and mechanical design of buried welded steel water pipelines subjected to earthquake action. Both transient (wave shaking) and permanent ground actions (from tectonic faults, soil subsidence, landslides and liquefaction-induced lateral spreading) are considered. In the first part of the paper, following a brief presentation of seismic hazards, modelling of the interacting pipeline-soil system is discussed, in terms of either simple analytical models or more rigorous finite elements, pinpointing their main features. In the second part of the paper, pipeline resistance is outlined, with emphasis on the corresponding limit states. Possible mitigation measures for reducing seismic effects are also presented, and the possibility of employing gasketed joints in seismic areas is discussed. Finally, the above analysis methodologies and design provisions are applied in a design example of a buried steel water pipeline, located in an area with severe seismic action.

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