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Case studies of pipeline repairs following extreme ground movement events demonstrate how the displacement accommodating mechanisms of hybrid-segmented pipelines perform favorably (requiring less repairs to maintain serviceability) compared with traditional pipeline systems. Hybrid-segmented pipelines utilize a joint-locking mechanism that allows a pipe segment to move a prescribed displacement before engaging the next segment of pipe. Given the recent emergence of these technologies, there is a need to understand how these systems respond to relative movement between the pipeline system and soil because this interaction directly impacts the soil resistance accumulated along the joint and at the connections. Frictional resistance along a pipe barrel and the passive resistance developed at the face of an enlarged connection can be quantified for a single pipe segment; however, the development of these forces along a pipeline system, composed of multiple segments, is dependent on how the pipeline accommodates induced displacements. This study establishes an analytical framework that captures the displacement accommodation mechanisms of hybrid-segmented pipelines under axial ground movement and estimates the subsequent accumulations of resistance (frictional and passive) along the system. The proposed framework determines how a series of pipe segments engage and the subsequent total resistance developed based on inputs for pipe, connection, and soil properties. The proposed framework is validated with established numerical models and previous analytical approaches, demonstrating favorable comparisons. Although previous analytical models can estimate the total geotechnical demands on a pipeline system for various levels of ground movement, the proposed analytical framework is able to capture the allowable displacement and joint-locking mechanisms that uniquely differentiate hybrid-segmented systems from traditional pipelines. The analytical framework presented in this study can be used by designed engineers to make informed decisions on which pipeline systems are best suited for various conditions and ground movement scenarios. [ABSTRACT FROM AUTHOR]

Innovative hybrid-segmented pipeline systems are being used more frequently in practice to improve the performance of water distribution pipelines subjected to permanent ground deformation (PGD), such as seismic-induced landslides, soil lateral spreading, and fault rupture. These systems employ joints equipped with anti-pull-out restraints, providing the ability to displace axially before locking up and behaving as a continuous pipeline. To assess the seismic response of hazard-resistant pipeline systems equipped with enlarged joint restraints to longitudinal PGD, this study develops numerical and semi-analytical models considering the nonlinear properties of the system, calibrated from large-scale test data. The deformation capacities of two hybrid-segmented pipelines are investigated: (i) hazard- resilient ductile iron (DI) pipe and (ii) oriented polyvinylchloride (PVCO) pipe with joint restraints capable of axial deformation. The numerical analysis demonstrates that, for the conditions investigated, the maximum elongation capacity of the analyzed DI pipe system is greater than that of the PVCO pipeline. The implemented semi-analytical approach revealed that the pipeline performance improves strongly by increasing the allowable joint displacement. Comparison of the numerical results with analytical solutions reported in recent research publications showed excellent agreement between the two approaches, highlighting the importance of assigning appropriate axial friction parameters for these systems. Key words: longitudinal ground movement, hybrid-segmented pipeline, seismic performance, soil-pipeline interaction, analytical model, numerical analysis. Les systemes de canalisations hybrides innovants sont de plus en plus utilises dans la pratique pour ameliorer les performances des canalisations de distribution d'eau soumises a une deformation permanente du sol (DDP), comme les glissements de terrain provoques par les seismes, l'epandage lateral du sol et la rupture de failles. Ces systemes utilisent des joints equipes de dispositifs de retenue anti-extraction, offrant la possibilite de se deplacer axialement, avant de se verrouiller et de se comporter comme un pipeline continu. Afin d'evaluer la reponse sismique des systemes de pipelines resistants aux risques equipes de joints de retenue elargis au DPI longitudinal, cette etude developpe des modeles numeriques et semi-analytiques, en tenant compte des proprietes non lineaires du systeme, calibres a partir de donnees d'essai a grande echelle. Les capacites de deformation de deux pipelines a segments hybrides sont etudiees: (i) un tuyau en fonte ductile (DI) resistant aux risques et (ii) un tuyau en polychlorure de vinyle (PVCO) oriente avec des joints de retenue capables de se deformer axialement. L'analyse numerique demontre que, pour les conditions etudiees, la capacite d'allongement maximale du systeme de tuyauterie DI analyse est superieure a celle du pipeline PVCO. L'approche semi-analytique mise en reuvre a revele que la performance du pipeline s'ameliore fortement en augmentant le deplacement admissible des joints. La comparaison des resultats numeriques avec les solutions analytiques presentees dans de recentes publications de recherche a montre un excellent accord entre les deux approches, soulignant l'importance d'attribuer des parametres de frottement axial appropries pour ces systemes. [Traduit par la Redaction] Mots-cles : analyse numerique, mouvement longitudinal du sol, pipeline hybride segmente, performance sismique, interaction sol-pipeline, modele analytique., 1. Introduction Buried pipelines installed in seismic regions are susceptible to the effects of transient ground deformation (TGD) due to seismic wave propagation and permanent ground deformation (PGD) resulting from [...]

The structural integrity of buried pipelines is threatened by the effects of Permanent Ground Deformation (PGD), resulting from seismic-induced landslides and lateral spreading due to liquefaction, requiring accurate analysis of the system performance. Analytical fragility functions allow us to estimate the likelihood of seismic damage along the pipeline, supporting design engineers and network operators in prioritizing resource allocation for mitigative or remedial measures in spatially distributed lifeline systems. To efficiently and accurately evaluate the seismic fragility of a buried operating steel pipeline under longitudinal PGD, this study develops a new analytical model, accounting for the asymmetric pipeline behavior in tension and compression under varying operational loads. This validated model is further implemented within a fragility function calculation framework based on the Monte Carlo Simulation (MCS), allowing us to efficiently assess the probability of the pipeline exceeding the performance limit states, conditioned to the PGD demand. The evaluated fragility surfaces showed that the probability of the pipeline exceeding the performance criteria increases for larger soil displacements and lengths, as well as cover depths, because of the greater mobilized soil reaction counteracting the pipeline deformation. The performed Global Sensitivity Analysis (GSA) highlighted the influence of the PGD and soil–pipeline interaction parameters, as well as the effect of the service loads on structural performance, requiring proper consideration in pipeline system modeling and design. Overall, the proposed analytical fragility function calculation framework provides a useful methodology for effectively assessing the performance of operating pipelines under longitudinal PGD, quantifying the effect of the uncertain parameters impacting system response. [ABSTRACT FROM AUTHOR]