In the last years, the tunnel fires have shown that the tunnel support structure is severely damaged at an extremely high fire impact. “In some tunnels, up to two thirds of the tunnel inner shell are shattered by explosion. The leftover concrete suffers a severe thermal damage. This combination can lead to structure collapse in the case of one-shell tunnels that are close to upper areas,” clarifies Matthias Zeiml of the Institute for Mechanics of Materials and Structures (IMWS) of the Vienna Universisty of Technology.
He and his colleague from Munich, Roman Lackner (lecturer at IMWS), analyzed, as part of a three-year FWF-project, the “transportation processes in concrete at high temperatures.” “The blowup of the concrete sticks is a consequence of the thermal wedging and of the steam pressure, which develops in the heated concrete and which cannot escape.
These flattenings sometimes reach far behind the reinforced steel,” explains Zeiml. At the same time, University of Technology Professor Ulrich Schneider of the Institute for Building Construction and Technology and the Research Institute of the Austrian Cement Industry (VÖZFI) analyzed the effect of minuscule polypropylene fibers (carpet fibers) which are blended into the concrete. When the concrete is warmed up, adding a few millimeter-long fibers produces channels through which the water steam can escape. This way, flatennings can be effectively prevented.
The results of this fundamental research are now useful to researchers for the KIRAS-Project (Austrian Support Program for Safety Research) of the BMVIT, which received a grant in June. This research project benefits from the participation of a consortium that consists of University Institutes of the Vienna University of Technology and the Vienna University of Natural Resources and Applied Life Sciences, infrastructure construction developers (ÖBB, ASFiNAG, Wiener Linien) as well as engineering companies and research laboratories. At the forefront of research there is the development of a new evaluation pattern which for the first time facilitates the prognosis of the vital processes which are influenced by the structure support behavior. “Our project partners - ÖBB, ASFiNAG, and Wiener Linien – are interested in a close to reality prognosis of the tunnel safety level under fire impact. Moreover, we have to answer questions regarding issues such as the need for a temporary support and the extent of the necessary restructuring measures for different fire scenarios,” adds Lackner.
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24.01.2018 | National Science Foundation
Magnetic liquids improve energy efficiency of buildings
16.01.2018 | Friedrich-Schiller-Universität Jena
Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.
The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...
An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.
The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
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