Geohazard assessment and seismic design of compressor stations
Compressor stations are very essential components of any high-pressure gas pipeline. The main issues of the design and construction of any compressor station are undoubtedly the safety and serviceability. It is evident that both of them depend mainly on the capability of the design group (a) to assess realistically all the local site conditions (topographical, geological, geotechnical, etc.), (b) to choose the optimum type and size of the compressor station, and (c) to design the compressor station accordingly in order to withstand all the potential loadings and hazards (e.g. gravity, pressure, differential settlements, etc.). Nevertheless, in areas characterized by moderate or high seismicity the design of a compressor station may be a more challenging and demanding task since both safety and serviceability are directly related to the earthquake-related geohazards and the seismic vulnerability of the compressor station under consideration. The term "earthquake-related geohazards" is used to describe various geological/geotechnical phenomena apart from strong ground motion, such as active-fault rupture propagation, earthquake-triggered slope instabilities and soil-liquefaction phenomena (i.e. buoyancy, settlements or lateral spreading). Therefore, the main emphasis of this study is on the seismic risk of new or existing compressor stations. The seismic risk may be estimated by the assessment of the earthquake-related geohazards and the realistic estimation of the seismic (i.e. dynamic) distress of the compressor station. The first part of the study is devoted on the qualitative and quantitative assessment of the main earthquake-related geohazards, while in the second part the main issues related to the seismic response and vulnerability of compressor stations will be presented through similar case histories and case studies of static, quasi-static and dynamic soil-structure interaction.