Simulation-Based Seismic Risk Assessment of Gas Distribution Networks

The basic function of a gas distribution sys- tem, essentially composed of buried pipelines, reduc- tion stations, and demand nodes, is to deliver gas from sources to end users. The objective of the article is to discuss the evaluation of seismic risk of gas networks in compliance with the performance-based earthquake en- gineering framework adapted to spatially distributed sys- tems. In particular, three issues are addressed: (1) spatial seismic hazard characterization in terms of ground shak- ing and permanent ground deformation; (2) analysis of system’s vulnerability via fragility curves; (3) seismic per- formance evaluation via computer-aided simulation. As an application, the seismic risk analysis of L’Aquila (cen- tral Italy) gas distribution network, a 621-km mid- and low-pressure pipeline system was considered. The anal- yses were performed with reference to the mid-pressure part of the network, through an object-oriented software, specific for risk assessment of lifelines, developed by the authors. Results in terms of connectivity-based per- formance indicators are presented and discussed, along with a performance disaggregation analysis carried out to evaluate the contribution of the components of the sys- tem to the risk.