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.
Construction Impact Guide
18.05.2018 | Hochschule RheinMain
New, forward-looking report outlines research path to sustainable cities
24.01.2018 | National Science Foundation
There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.
The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
21.08.2018 | Ecology, The Environment and Conservation
21.08.2018 | Life Sciences
21.08.2018 | Power and Electrical Engineering