Post-Earthquake Physical Damage Assessment for Gas Networks (original) (raw)
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This paper describes the assessment of the damage of the local gas network in the 2009 L’Aquila earthquake (Mw 6.3). The analysis focuses on the main components of the low and medium distribution networks, namely pipes, valves, and demand nodes. The processing of the technical reports from Enel Rete GAS (the unique gas network operator in the affected region), describing the repairs and replacements activities following L’Aquila earthquake is presented, and the resulting damage scenario is discussed. In particular, the density of repairs activities have been overlaid to the ground motion in the affected area, described in terms of peak ground velocity. Finally, the repair ratios (number of repairs per km) for the pipelines were compared with repair ratio fragility functions available in literature.
Bulletin of Earthquake Engineering, 2013
Despite the seismic vulnerability of gas systems and the significance of the direct and indirect consequences that loss functionality might have on large communities, the analysis of the earthquake performance and of post-earthquake management for this kind of distribution networks appears under-represented in the international literature, with respect to other lifeline systems. To contribute on this matter, the study presented comprises an investigation of the impact of L'Aquila 2009 earthquake (M w 6.3) on the performance of the local medium-and low-pressure gas distribution networks. The assessment of the physical impact of the earthquake to the buried components of network, namely pipes, valves, and demand nodes, was carried out when processing post-earthquake repair activity reports. Repair data, along with geometrical and constructive features, were collected in a geographic information system linked to the digitized maps of the network, and compared with the interpolated map of recorded transient ground motion, measured in terms of peak ground velocity (i.e., a Shakemap TM ). The impact of permanent ground deformation was also investigated and found to be limited in the study area. The resulting observed repair rates (number of repairs per km), presented for different pipeline materials, were compared with repair ratio fragility functions available in literature, showing relatively agreement especially to those for steel pipes, likely also because of the uncertainties in the estimations. Finally, the management of the L'Aquila gas system in the emergency phase and the resilience (functionality recover versus time) of the system was discussed.
Performance of the L'Aquila (central Italy) gas distribution network in the 2009 (Mw 6.3) earthquake
2013
Despite the seismic vulnerability of gas systems and the significance of the direct and indirect consequences that loss functionality might have on large communities, the analy- sis of the earthquake performance and of post-earthquake management for this kind of dis- tribution networks appears under-represented in the international literature, with respect to other lifeline systems. To contribute on this matter, the study presented comprises an investi- gation of the impact of L'Aquila 2009 earthquake (Mw 6.3) on the performance of the local medium- and low-pressure gas distribution networks. The assessment of the physical impact of the earthquake to the buried components of network, namely pipes, valves, and demand nodes, was carried out when processing post-earthquake repair activity reports. Repair data, along with geometrical and constructive features, were collected in a geographic informa- tion system linked to the digitized maps of the network, and compared with the inter...
Serviceability of Natural Gas Distribution Networks After Earthquakes
Journal of Earthquake and Tsunami, 2013
The concept of disaster resilience has received considerable attention in recent years and it is increasingly used as an approach for understanding the dynamics of natural disaster systems. No models are available in literature to measure the performance of natural gas network, therefore, in this paper, a new performance index measuring functionality of gas distribution network have been proposed to evaluate the resilience index of the entire network. It can be used for any type of natural or manmade 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 which were affected by 2009 earthquake have been used as case study. Together the pipeline network covers an area of 136 km2, with 3 M/R stations and 16 regulation groups. The software SynerGEE has been used to simulate different scenario events. The numerical results showed that, during emergency, to ensure an acc...
Application to L’Aquila Gas Network
Geotechnical, Geological and Earthquake Engineering, 2014
This chapter, after an introduction presenting the general framework for the seismic risk assessment of a gas network according to the SYNER-G methodology (Chap. 2), describes the case study of L'Aquila (central Italy) gas distribution system, a 621 km pipeline network managed by Enel Rete Gas s.p.a. and operating at medium-and low-pressure. Subsequently, the main features regarding the implementation of the application study within the SYNER-G framework are reported, and the process for the seismic performance characterization is summarized. Then, the risk analysis of the system is described, and results in terms of connectivity-based performance indicators are presented. 283 284 S. Esposito and I. Iervolino
Seismic Risk Analysis of Lifelines: Preliminary Results for the Case-Study of L'Aquila ENEL Rete Gas
Proceedings of 15WCEE – 15th World Conference on Earthquake Engineering
This paper presents the seismic risk assessment of L'Aquila gas distribution network in a performance-based earthquake engineering framework. The study was structured in three basic activities: (1) seismic hazard characterization both in terms of ground motion and permanent ground deformation; (2) characterization of system's vulnerability via fragility curves available in literature; (3) performance evaluation in terms of connectivity. In the paper all issues involved in seismic risk analysis of this kind of systems are discussed with respect to a selected part of the whole network. In particular, the importance of modelling spatial correlation of ground motion and geotechnical hazard on risk assessment was investigated. Results indicate that the system performance may be underestimated when spatial correlation and ground failure are ignored. Moreover, the implications of using fragility curves for compressor stations for the reduction cabins, as suggested in literature, were also addressed, and the necessity of developing specific fragilities was pointed out.
Simulation-Based Seismic Risk Assessment of Gas Distribution Networks
Computer-Aided Civil and Infrastructure Engineering, 30(7), 508–523, DOI: 10.1111/mice.12105, 2015
The basic function of a gas distribution system, essentially composed of buried pipelines, reduction 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 engineering framework adapted to spatially distributed systems. In particular, three issues are addressed: (1) spatial seismic hazard characterization in terms of ground shaking and permanent ground deformation; (2) analysis of system's vulnerability via fragility curves; (3) seismic performance evaluation via computer-aided simulation. As an application, the seismic risk analysis of L'Aquila (central Italy) gas distribution network, a 621-km mid- and low-pressure pipeline system was considered. The analyses 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 performance indicators are presented and discussed, along with a performance disaggregation analysis carried out to evaluate the contribution of the components of the system to the risk.
L’Aquila Earthquake April 6th, 2009: the Damage Assessment Methodologies
Different Methodologies were adopted during the field investigations and the assessment of damage in structures following the Abruzzo (Italy) Earthquake of the 6th April 2009. The scope of the paper is to review the different methodologies adopted by the COST Action C26 Field Investigation Team, and the methodologies considered by the EEFIT Team in the field assignments conducted in the aftermath of the earthquake. The COST C26 team based the assignment on a number of methodologies: the AeDES (AeDES & AeDES Modified) and the MEDEA, used by the Italian Civil Protection for Masonry and Reinforced Con-crete structures; the EEFIT team methodology included the general observations, the rapid survey using EMS-98, and the detailed survey. The aim of the paper is to review the methods, assess the type and extent of data collected and the scale considered, and analyse each methodology with respect to the scope of the tasks undertaken. A critical assessment of the methods, is presented with r...
Real Time damage scenario : case study for the L ’ Aquila earthquake
2012
In this paper we describe the methodology developed to calculate real time damage scenario for a seism ic event, using a mechanical based method for the vulnerabili ty assessment of buildings, Ground Motion Predictio n Equations, exposure data and local site effects. Th e methodology has been developed for rapid assessme nt at regional scales, and is tested here by comparing th e results with real damage data collected after the L’Aquila earthquake. In the followings we compare the result s of scenarios obtained with information of differe nt level of detail and accuracy, from national exposure and soi l data used in conjunction with first hand earthqua ke information, to exposure data and site effects comi ng from detailed survey that have become available in the months following the event.
Real – Time Earthquake Damage Assessment of Buried Gas Pipelines
2014
Okan İLHAN 1 and A. Can ZÜLFİKAR 2 It is widely known that recent earthquakes have significantly influenced lifeline structures such an extent that even if there is not any damage in structures or any facilities on ground, the fracture of gas pipelines resulting in gas leakage leads to fires, economic losses and disability of lifeline networks. Therefore, the possibility of encountering with such a great hazard makes inroads into developing a method to assess the performance of available gas pipeline networks and to envisage the way of reinforcing them in the case of considerable damages under earthquake excitation. In general, researchers have dealt with the quantification of lifeline hazard in that some of them appeal to the equations which are improved after the occurrence of significant earthquake by computing the number of pipeline breakages/leakages on site with respect to distance. (km) This route allows people to constitute fragility curves including relationship between rep...