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Increasing rockfall activity in the European Alps raises the need for designing systems protecting Alpine infrastructure. So far, layout of rockfall protection layers was carried out in a quasi-deterministic manner. This paper is concerned with the extension towards a semi-probabilistic design of the thickness of gravel layers covering steel pipelines. Quantities with little scatter such as geometric dimensions and elasto-plastic material constants of steel and gravel are treated as deterministic. By contrast, strongly scattering quantities such as the indentation resistance of gravel, R, and rockfall characteristics including boulder mass m and height of fall h f are considered as probabilistic variables. While 5 and 95% quantiles of R (obtained from statistical evaluation of a series of real-scale impact tests onto gravel) represent probability-based interval bounds for designing the gravel layer thickness, the lack of statistical data from rare rockfall events motivates to follow the philosophy of EUROCODE 1, i.e., to define a design rockfall: m = 10,500 kg and h f = 80 m. Based on this input, a standard burying depth of steel pipelines ( H = 1 m) is assessed, by comparing estimates of (i) boulder penetration depth into gravel and of (ii) the maximum impact force, respectively, with corresponding quantities related to a suitable real-scale impact test. This comparison shows the need to increase the height of the gravel overburden. In order to prove that a gravel layer thickness H = 2.7 m is sufficient to prevent the pipeline from inelastic deformations when the structure is hit by the design rockfall, several structural analyses with different values for R are carried out. This is done by means of a validated Finite Element model. As a by-product of the proposed semi-probabilistic design procedure, three different deformation modes of the hit pipeline are identified. [ABSTRACT FROM AUTHOR]

Summary This paper explores the possibility of using ring-width measurements derived from string instruments as a potential source of palaeoclimate information. From a data-base of 1800 measured series, we have identified two sub-sets that compare well with living high elevation spruce (Picea abies (L.) Karst) chronologies from the Bavarian Forest and Austrian Alps. The problems of using historical tree-ring data for dendroclimatic purposes are addressed and by combining the living and historic ring-width data from these two regions, a preliminary proxy of past June/July mean temperatures is developed. This proxy summer temperature record shows striking similarities with a tree-ring based temperature reconstruction for the Central Eastern Alps, the CLIMHIST June/July temperature record from Switzerland and glacial records from the Austrian Alps. This explorative study demonstrates that ring-width series from string instruments may allow the identification of generalised source regions of wood used for instrument making and, most importantly, provide a new unique source for palaeoclimate information at a variety of both temporal and spatial scales for high elevations in central Europe. [ABSTRACT FROM AUTHOR]