The Meaning of Eurocode 8 and Induced Seismicity for Earthquake Engineering in The Netherlands

The Netherlands is one of the few European countries where seismic loading is not a dominant part of the national codes. Only for very special structures, earthquakes are regarded as a separate loading case. Until now, Eurocode 8 (EC8) is not part of Dutch building laws nor is there an official Dutch translation. Tectonic seismicity mainly occurs in the southern part of The Netherlands. The Dutch code NEN 6702 has a zonation map which shows horizontal peak accelerations of 0.01g to 0.1g for a return period of 5000 years. However, this seismic zonation map is yet not coherent with the EC8 National Annexes for Belgium and Germany. Induced seismicity due to the exploitation of natural gas is mainly observed in the northern part of The Netherlands. Induced earthquakes in the Netherlands have been observed at shallow depths with magnitudes up to ML = 3.5. Recorded strong accelerations are usually short in duration but have incidentally reached 0.3g. Currently, a study group is investigating the suitability of EC8 approach for Dutch conditions, the different seismic engineering approaches in Belgium and Germany, the implication of induced seismicity and a uniform engineering approach for sensitive structures, adopting (seismic) risk assessment

A combined risk analysis approach for complex dam-levee systems

[EN] In many areas of the world, dams and levees are built to reduce the likelihood of flooding. However, if they fail, the result can be catastrophic flooding beyond what would happen if they did not exist. Therefore, understanding the risk reduced by the dam or levee, as well as any risk imposed by these flood defences is of high importance when determining the appropriate risk reduction investment strategy. This paper describes an approach for quantifying and analysing risk for complex dam-levee systems, and its application to a real case study. The basis behind such approach rely on the potential of event tree modelling to analyse risk from multiple combinations of load-system response-consequence' events, tested by the authors for a real case study. The combined approach shows how the contribution to system risk of each sub-system can be assessed. It also describes how decisions on risk mitigation measures, at the individual asset scale, can and should be informed in terms of how they impact the overall system risk.This work was supported by Spanish Ministry of Economy and Competitiveness (MINECO) [BIA 2013-48157-C2-1-R].Castillo-Rodríguez, J.; Needham, J.; Morales Torres, A.; Escuder Bueno, I. (2017). A combined risk analysis approach for complex dam-levee systems. Structure and Infrastructure Engineering. 13(12):1624-1638. https://doi.org/10.1080/15732479.2017.1314514S16241638131

Upon impact: the fate of adhering <i>Pseudomonas fluorescens</i> cells during Nanofiltration

Nanofiltration (NF) is a high-pressure membrane filtration process increasingly applied in drinking water treatment and water reuse processes. NF typically rejects divalent salts, organic matter, and micropollutants. However, the efficiency of NF is adversely affected by membrane biofouling, during which microorganisms adhere to the membrane and proliferate to create a biofilm. Here we show that adhered Pseudomonas fluorescens cells under high permeate flux conditions are met with high fluid shear and convective fluxes at the membrane-liquid interface, resulting in their structural damage and collapse. These results were confirmed by fluorescent staining, flow cytometry, and scanning electron microscopy. This present study offers a 'first-glimpse' of cell damage and death during the initial phases of bacterial adhesion to NF membranes and raises a key question about the role of this observed phenomena during early-stage biofilm formation under permeate flux and cross-flow conditions.European Research Council (ERC

Value of information in retrofitting of flood defenses

Dikes and levees play a crucial role in flood protection. The main causes of levee failures are of geotechnical nature; geotechnical failure modes are also the main contributors to the probability of failure of flood defences due to the typically large uncertainties in ground conditions. Hence, information on ground conditions and soil properties is crucial in safety assessments and retrofitting designs of levees. The present paper demonstrates how we can reduce these uncertainties and how we can provide input for rational decision making on investments in monitoring and site investigation. If working in a framework with an explicit target reliability, the value of such information can be expressed in terms of the savings that can be achieved in retrofitting costs. The key ingredients of the approach are Bayesian posterior analysis for reliability updating by incorporating the information from various sources and Bayesian (pre-posterior) decision analysis for estimating the uncertainty and expected values of the consequences and costs of the considered decision options. The optimal strategy is the one with the least expected cost to meet the pre-set reliability target (e.g. by a safety standard). Several examples and case studies addressing different sources of information, such as field observations and piezometer monitoring during floods or site investigation by Cone Penetration Tests (CPT), illustrate the impact of reliability updating and suggest that investments in inspection and monitoring are often worthwhile, especially when the prior uncertainties are large.Non UBCUnreviewedThis collection contains the proceedings of ICASP12, the 12th International Conference on Applications of Statistics and Probability in Civil Engineering held in Vancouver, Canada on July 12-15, 2015. Abstracts were peer-reviewed and authors of accepted abstracts were invited to submit full papers. Also full papers were peer reviewed. The editor for this collection is Professor Terje Haukaas, Department of Civil Engineering, UBC Vancouver.Facult

Life-Cycle-Cost-Based Bridge Management in the Netherlands

ABSTRACT: The main reason for the existence of transportation systems is public interest. From this point of view, any road program should be driven by various societal aspects. In this paper societal aspects are schematized into two categories, public and politics. The position of the engineer responsible for bridge management within the road agency is described in general and elaborated for two fields important for bridge management: ‘reliability and structural safety’ and ‘maintenance’. The paper gives an overview of the discussion on these fields in the Netherlands. Key objectives are to establish open communication and to place this in a life-cycle perspective. The role of the managing authority is to create a coherent system having an interface to the societal domain.

Protocols for communication and governance of risks

The aim of this paper is to explain the need to organize the development of standard protocols for communication about major public risks. Tragic events, such as inadequate earthquake preparedness or great unnecessary losses of life due to public misunderstandings underline the importance of such protocols to protect the public and support confidence in government and experts. The required contents of such protocols are suggested in outline. It is concluded that the need is urgent internationally to organize the development of standard protocol paradigms, one for scientific-professional analysts and another for authorities' communications to the public.Non UBCUnreviewedThis collection contains the proceedings of ICASP12, the 12th International Conference on Applications of Statistics and Probability in Civil Engineering held in Vancouver, Canada on July 12-15, 2015. Abstracts were peer-reviewed and authors of accepted abstracts were invited to submit full papers. Also full papers were peer reviewed. The editor for this collection is Professor Terje Haukaas, Department of Civil Engineering, UBC Vancouver.Facult