Prodromos N. Psarropoulos

Parametric study of cantilever walls subjected to seismic loading

The design of flexible earth retaining structures under seismic loading is a challenging geotechnical problem, the dynamic soil‐structure interaction being of paramount importance for this kind of structures. Pseudo‐static approaches are often adopted but do not allow a realistic assessment of the performance of the structure subjected to the seismic motions. The present paper illustrates a numerical parametric study aimed at estimating the influence of the dynamic soil‐structure interaction in the design. A series of flexible earth retaining walls have been preliminary designed according to the requirements of Eurocode 7 and Eurocode 8—Part 5; their dynamic behaviour has been then evaluated by means of dynamic numerical simulations in terms of bending moments, accelerations and stress state. The results obtained from dynamic analyses have then been compared with those determined using the pseudo‐static approach.

OFFSHORE NATURAL GAS PIPELINES SUBJECTED TO KINEMATIC DISTRESS

Hydrocarbons are undoubtedly the main energy source of the twenty-first century. Over the last decades the increase in energy needs has led to the exploitation of an increasing number of offshore natural gas deposits. Typically, the long distances between natural gas deposits and urban and industrial centres necessitate the use of offshore pipelines. Such pipelines are very important infrastructures and any possible damage can cause serious problems and devastating consequences. Geohazards, such as strong ground motion, active faults, tsunamis, etc, consist crucial threats that an offshore pipeline has to overcome. Especially, kinematic distress caused by active faults or submarine landslides can impose a great risk to offshore pipelines due to the substantial permanent ground deformations. Furthermore, the extended areas that are affected by such phenomena, as well as the adverse submarine soil conditions, are also detrimental factors for the integrity of the pipelines. For this purpose, the aim of this work is to study numerically, utilizing the finite element method, the kinematic distress ) of an offshore natural gas pipeline due to a submarine landslide. Firstly, the developed numerical models are validated using available analytical solutions, and subsequently various parameters that affect the examined problem are investigated. The detailed parametric analysis covers among others, the impacted force on the pipeline, the landslide length, internal pressure levels, slope inclinations and diameter to thickness ratios. 1018 Available online at www.eccomasproceedia.org Eccomas Proceedia COMPDYN (2017) 1018-1031