- Resilience-Based Design of Natural Gas Distribution Networks
- G.P. Cimellaro ; O. Villa ; M. Bruneau
- Book Title / Journal: Journal of Infrastructure Systems
- Year: 2014 , Volume: 1943 , Series:
- Earthquake engineering
- Keywords: resilience ; Disaster resilience ; Vulnerability ; Gas networks ; Damage assessment ; Serviceability ; Resilience-based design
- The concept of disaster resilience has received considerable attention in recent years and is increasingly used as an approach for understanding the dynamic response to natural disasters. In this paper, a new performance index measuring the functionality of a gas distribution network has been proposed, which includes the restoration phase to evaluate the resilience index of the entire network. The index can also be used for any type of natural or artificial hazard, which might lead to the disruption of the system. The gas distribution network of the municipalities of Introdacqua and Sulmona, two small towns in the center of Italy that were affected by the 2009 earthquake, has been
used as a case study. The pipeline network covers an area of 136 km2, with three metering pressure reduction (M/R) stations and 16 regulation groups. Different analyses simulating different breakage scenario events due to an earthquake have been considered. The numerical results
showed that the functionality of the medium-pressure gas distribution network is crucial for ensuring an acceptable delivery service during the postearthquake response. Furthermore,the best retrofit strategy to improve the resilience index of the entire network should include emergency shutoff valves along the steel pipes.
- Physical infrastructure interdependency and regional resilience index after the 2011 Tohoku Earthquake in Japan
- G.P. Cimellaro ; D. Solari ; M. Bruneau
- Book Title / Journal: Earthquake Engineering & Structural Dynamics
- Year: 2014 , Volume: , Series:
- Earthquake engineering
- Keywords: resilience ; lifelines ; infrastructures ; recovery
- A resilience index is used to quantify preventive measures, emergency measures, and restoration measures of complex systems, such as physical infrastructures, when they are subjected to natural disasters like earthquakes, hurricanes, floods, etc. Interdependencies among these systems can generate cascading failures or amplification effects, which can also affect the restoration measures right after an extreme event and generate a reduction of the resilience index. In this article, a method is proposed to evaluate the physical infrastructure resilience of a region affected by a disaster considering infrastructure interdependency. It is illustrated using available restoration curves from the March 11 2011 Tohoku Earthquake in Japan. The weights assigned to each infrastructure, which are used to determine resilience, are evaluated using the degree of interdependency indices which are obtained by time series analysis. Results show that the weight coefficients thus obtained do not influence the resilience index significantly; however, the methodology proposed is unbiased from subjective judgment and is able to identify the critical lifelines. Furthermore, the results of the case study presented here suggest that to obtain meaningful estimation of the weight coefficients, it is necessary to consider the period range between two perturbations (e.g., main shock and aftershock). Future infrastructure disruption data (from this and other earthquakes) would be needed to generalize this finding that will allow also to quantify the changes in the restoration curves caused by the magnitude and distance of the shocks from the epicenter, as well as the intrinsic properties of the physical infrastructures.