The damage on supply and drainage water networks is a serious cause of economic disruption for urban systems affected by earthquakes. Among various concerns, the ruptures of sewer pipes and manholes ...generated by liquefaction determine a particularly severe sanitary hazard and require extensive, costly and time-consuming repairs. Quantitative risk assessment carried out with the characterisation and geographical mapping of seismic hazard, subsoil susceptibility, physical and functional vulnerability of the exposed elements, enables to estimate losses, identify weaknesses, inspire strategies to mitigate the impact of earthquakes and improve resilience. The present study deals with the physical vulnerability of sewer pipelines. Empirical fragility functions are derived from the evidences of liquefaction induced in Urayasu (Japan) by the 2011 Tohoku-Oki earthquake (Mw9.0). The spatial distribution of seismic signals, subsoil characteristics, pipes and surveyed damages are reconstructed in a GIS platform. An articulated methodology is developed to correlate variables and compensate their limited spatial correspondence, exploiting the complete coverage of the area with terrestrial settlements measured by LiDAR and their strong correlation with damage. Finally, ruptures of pipes are probabilistically quantified adopting a common liquefaction severity indicator as engineering demand parameter and measuring the efficiency of relations with statistical tests.
In engineering practice, the liquefaction potential of a sandy soil is usually evaluated with a semi-empirical, stress-based approach computing a factor of safety in free field conditions, defined as ...the ratio between the liquefaction resistance (capacity) and the seismic demand. By so doing, an estimate of liquefaction potential is obtained, but nothing is known on the pore pressure increments (often expressed in the form of normalized pore pressure ratio r
u
) generated by the seismic action when the safety factor is higher than 1. Even though r
u
can be estimated using complex numerical analyses, it would be extremely useful to have a simplified procedure to estimate them consistent with the stress-based approach adopted to check the safety conditions. This paper proposes such a procedure with reference to both saturated and unsaturated soils, considering the latter as soils for which partial saturation has been artificially generated with some ground improvement technology to increase cyclic strength and thus tackle liquefaction risk. A simple relationship between the liquefaction free field safety factor FS, and r
u
(S
r
) is introduced, that generalizes a previous expression proposed by Chiaradonna and Flora (Geotech Lett, 2020.
https://doi.org/10.1680/jgele.19.00032
) for saturated soils. The new procedure has been successfully verified against some experimental data, coming from laboratory constant amplitude cyclic tests and from centrifuge tests with irregular acceleration time histories for soils having different gradings and densities.
Every year the food produced and wasted consumes a volume of water equal to 250 km3, requires around 30% of the world agricultural land, and it is responsible for the emission of 3,3 billion tons of ...greenhouse gases. The direct economic consequences of food waste are ranging around 750 billion dollars per year (FAO source). i-REXFO designs an innovative business model with the objective of reducing significantly the amount of landfilled food waste. The actions are economically sustained by public incentives, tax reductions and private revenues from energy valorization of residual food waste. Uptaking the good practices from other EU countries (Denmark) the project will develop a tool to design the integrated model, optimize it from a technical, economic and environmental point of view and transfer it to other EU regions. i-REXFO will increase consumer awareness on food waste reduction in retail malls and HORECA while facilitating the sale and donation to charities and food banks of close to expiration and aesthetically not adequate food; it will also remove the barriers that hamper the use of food residues in biogas plants. The actions are economically sustained from energy valorization of food waste in biogas plant that use the digestate as fertilizer, closing the cycle. I-REXFO will achieve an overall reduction of 17000 tons/year of food waste landfilled during the project duration and in the after life phase. This will correspond to an overall reduction of 41000 tons of CO2 equivalent emissions.
Worldwide, a large set of initiatives have been carried out aiming to understand the benefits offered by Nature-Based Solutions (NBS) in urban areas. The European Commission (EC) has founded ...different projects that have performed scientific literature reviews regarding this topic. To objectively compare their results and consolidate the consensus about the impacts and benefits of NBS, we performed a text mining analysis. This methodology coupled with a visual representation of the data allowed to convert the EC funding projects reports (corpus) into a meaningful structured analysis. This method demonstrated that despite the different literature review methodologies of each report, there are common trends exhibited by the results, e.g., the NBS installation as a strategy of urban resilience, the recognition of ecosystem services (ESS) delivered by nature in urban spaces, or the importance of the EC’s supporting role in the promotion of NBS. In addition, some network specific trends have also emerged and complemented the analysis: the assessment of the NBS performance with indicators, the participatory planning approach to NBS (involving citizen and local communities) and the economic value of their services.
In the framework of the multi-disciplinary LIQUEFACT project, funded under the European Commission’s Horizon 2020 program, the LIQUEFACT Reference Guide software has been developed, incorporating ...both data and methodologies collected and elaborated in the project’s various work packages. Specifically, this refers to liquefaction hazard maps, methodologies and results of liquefaction vulnerability analysis for both building typologies and critical infrastructures, liquefaction mitigation measures as well as cost-benefit considerations. The software is targeting a wider range of user groups with different levels of technical background as well as requirements (urban planners, facility managers, structural and geotechnical engineers, or risk modelers). In doing so, the LIQUEFACT software shall allow the user assessing the liquefaction-related risk as well as assisting them in liquefaction mitigation planning. Dependent on the user’s requirements, the LIQUEFACT software can be used to separately conduct the liquefaction hazard analysis, the risk analysis, and the mitigation analysis. At the stage of liquefaction hazard, the users can geo-locate their assets (buildings or infrastructures) against the pre-defined macrozonation and microzonation maps in the software and identify those assets/sites that are potentially susceptible to an earthquake-induced liquefaction damage hazard. For potentially susceptible sites the user is able to commission a detailed ground investigation (e.g. CPT, SPT or V
S30
profile) and this data can be used by the software to customise the level of susceptibility to specific site conditions. The users can either use inbuilt earthquake scenarios or enter their own earthquake scenario data. In the Risk Analysis, the user can estimate the level of impact of the potential liquefaction threat on the asset and evaluate the performance. For the Mitigation Analysis, the user can develop a customized mitigation framework based on the outcome of the risk and cost-benefit analysis.
PDF
