Vulnerability assessment of natural gas network

The natural gas network, as well as the road network, the electricity network, and the sewers, represent strategic infrastructures from both an economic and social point of view. Damage to gas pipelines can cause interruption of energy production if the connection with thermal power plants is interrupted. It can affect everyday life, blocking the gas transportation toward homes, schools, hospitals, and any other urban facility. This thesis work focuses on assessing the seismic vulnerability of urban natural gas networks. Pipeline damage produced by ground shaking and permanent ground deformation is calculated through a physical-based methodology. A simulation tool called Pandapipes which is based on the Python programming language was used. To define the fluid-dynamic and geometric characteristics of the network, the design guidelines provided by the Italian technical regulations were followed. A simplified, scenario-based seismic hazard characterization is used to test the capabilities of the implemented computational framework. The proposed vulnerability analysis allows to estimate the effects of pipeline damages in terms of gas leaks and pipe breaks. Pandapipes model is updated to evaluate the variation of the thermodynamic characteristics of the gas network. The proposed computational framework allows to spatially identify the vulnerable points of the natural gas network since it is able to simulate the response of the pipeline subject to a seismic scenario. In order to test the validity of the computational framework, it is applied to a realistic virtual city model called Ideal City.