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Baden, Switzerland

Marcher T.,ILF Consulting Engineers ZT GmbH | John M.,JTC John Tunnel Consult | Hohberg J.-M.,IUB Engineering Ltd. | Fellner D.,Axpo Power AG | And 2 more authors.
Underground - The Way to the Future: Proceedings of the World Tunnel Congress, WTC 2013

A 1,000 MW pumped-storage plant is under construction at altitudes between 1,600 and 2,400m in the Glarner Alps of Switzerland, around 90 km south-east of Zurich. The machine and the transformer caverns are situated in Quintner Limestone with an overburden of 400 to 500 m. The 150 m long machine cavern has a height of 53 m and a width of approximately 30 m. The distance between both caverns was increased to 59 m to avoid overlapping plastic zones following the evaluation of geological conditions of the pilot tunnel. During construction it was found that geological conditions are more complex than expected, resulting in displacements varying to a large degree. That was why the design was reviewed by comparing the prognosis with the actual behaviour during excavation of the heading. The rock bolting system with regard to pattern and length was adjusted based on the results of numerical back analyses including sensitivity studies of the rock mass parameters. Additional 3D computations were performed to take account of the numerous intersecting galleries. During excavation of benches, additional rock bolting was provided in specific areas, where deformations continued over some time. © 2013 Taylor & Francis Group. Source

Muller U.,Engineering consortium Alpenstrom | Marclay R.,Engineering consortium Alpenstrom | Dunn J.,Engineering consortium Alpenstrom | Hohberg J.M.,Engineering consortium Alpenstrom | Hase M.,Axpo Power AG
Underground - The Way to the Future: Proceedings of the World Tunnel Congress, WTC 2013

"Linthal 2015" stands for a couple of records - Switzerland's largest hydro-power plant with Europe's longest concrete dam, a huge construction site at an altitude unique in Europe, and a stunning logistics with two of the largest cableways ever built. The paper describes the design philosophy, the development of the main project - covering the hydraulic system and the underground works - and the steps taken to optimize the layout, the dimensioning and the sequencing of works. Challenges are the ambitious time schedule, the logistics, the concerns for the delicate alpine nature, and last but not least the required high reliability and availability of the power plant. While this paper presents the broad picture of the project, another WTC'13 paper discusses the analysis and construction of the main caverns in more detail. © 2013 Taylor & Francis Group. Source

Proske D.,Axpo Power AG
12th International Conference on Applications of Statistics and Probability in Civil Engineering, ICASP 2015

Structures are exposed to an ensemble of natural hazards. Earthquakes and flooding's are the most recognized natural hazards, but structures also have to be safe under extreme weather conditions such wind and hurricanes, heat periods and colds, extreme rainfalls, hail and freezing rain. Some of this hazards are usually not investigated in detail, however based on statistical investigations, hazard curves and representative values of hazards can be defined, if required. They can be applied in probabilistic computations to achieve the probability of failure of the structures. Although major efforts have been undertaken in recent years to estimate the hazards and the representative values, we have to notice, that the validity of the provided natural hazards estimations by means of statistical investigations is limited due to confined sample populations. One of this causes is the recently increased knowledge using data with extreme values from non-instrumental periods, which heavily influences the outcome of the statistics, if considered. Newer statistical methods and the inclusion of historical data can, but need not necessarily improve results under all conditions. This development has also been observed in seismic loading estimation and in flooding hazard prognosis. Source

Proske D.,Axpo Power AG | Kurmann D.,Axpo Power AG | Cervenka J.,Cervenka Consulting
Beton- und Stahlbetonbau

Seismology and earthquake engineering have experienced major progress in the last decades. This progress is implemented in current modern codes of practice for the design of new structures. However for existing structures, mainly designed according to former codes of practice, a realistic estimation of the seismic robustness and ultimate load is also necessary. Often in such cases ambitious analyses are carried out. This paper describes the steps of such an analysis for a reinforced concrete structure, which is part of the critical infrastructure. In a first step the nonlinear force-deformation-curve is investigated by a pushover-curve. This curve is applied to an equivalent oscillator. Further dynamic properties of the oscillator are obtained from a soil-structure-interaction analysis. The oscillator is then exposed to various time-acceleration-sequences. This computation yields to a ductility demand. The ductility demand can be related to different earthquake intensities by scaling the time-acceleration-sequences. Finally the investigation was carried out twice, using characteristic and mean material properties. An overall deviation of the structural resistance can be provided by these parallel computations in combination with the deviation of the various time-acceleration-sequences. The results are used to construct a fragility curve and hence the ultimate seismic load bearing capacity. Copyright © 2013 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin. Source

Kurmann D.,Axpo Power AG | Proske D.,Axpo Power AG | Cervenka J.,Na Hrebenkach 55

Structures can be exposed to seismic loading. For structures of major importance, extreme seismic loadings have to be considered. The proof of safety for such loadings requires sophisticated analysis. This paper introduces an analysis method which of course still includes simplifications, but yields to a far more realistic estimation of the seismic load bearing capacity of reinforced concrete structures compared to common methods. It is based on the development of pushover curves and the application of time-histories for the dynamic model to a representative harmonic oscillator. Dynamic parameters of the oscillator, such as modal mass and damping are computed using a soil-structure-interaction analysis. Based on the pushover-curve nonlinear force-deformation-capacities are applied to the oscillator including hysteresis behaviour characteristics. The oscillator is then exposed to time-histories of several earthquakes. Based on this computation the ductility is computed. The ductility can be scaled based upon the scaling of the time-histories. Since both, the uncertainty of the earthquake by using different timehistories and the uncertainty of the structure by using characteristic and mean material values, are considered, the uncertainty of the structure under seismic loading can be explicitly represented by a fragility. © Carl Hanser Verlag, München. Source

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