Einsatz von Bergematerial im Tiefbau

An 38 Einzelstandorten im Ruhrgebiet wurden an D?mmen aus Bergematerial Felduntersuchungen und mit dem dort entnommenen Probenmaterial umfangreiche Laboruntersuchungen durchgeführt und durch geochemische Modellrechnungen erg?nzt. Als Ergebnis sind nach dem derzeitigen Erkenntnisstand folgende Parameter für eine Minimierung der Pyritoxidation in Verkehrsweged?mmen aus Bergematerial ma?gebend: Gesamt-Porenanteil, Wasserdurchl?ssigkeitsbeiwert und ausreichende Pufferkapazit?t des Bergematerials, M?chtigkeit, bodenmechanische Eigenschaften und Art der Bepflanzung der Abdeckung. Im Gegensatz zum Ministerialblatt Nr. 45 ist bei Bergematerial eine Unterscheidung zwischen Waschbergen und Wasch-Flotationsberge-Gemischen unter der im Rahmen dieser Untersuchungen dargestellten Betrachtungsweise nicht mehr notwendig, da nur noch nach dem Elutionsverhalten unterschieden wird. Es ergibt sich somit eine Einteilung in die “neuen” Waschberge I (mit Einsatzm?glichkeiten innerhalb und au?erhalb wasserwirtschaftlich bedeutender Gebiete) und Waschberge II (mit Einsatzm?glichkeiten au?erhalb wasserwirtschaftlich bedeutender Gebiete) in Anlehnung an das Ministerialblatt Nr. 45. Diese unterscheiden sich in ihrem wasserwirtschaftlichen und bodenmechanischen Anforderungen an Dammk?rper und Abdeckung.

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At 38 sites in the Ruhr district field and laboratory investigations were carried out on dams built out of mining debris and supplemented by geochemical model calculations and chemical investigations. As a result, the following factors are considered essential for minimizing pyrit oxidation inside a dam built out of mining debris: bulk porosity, water permeability and sufficient buffer capacity of the mining debris as well as thickness, soil mechanical properties and the kind of vegetation on the cover layer. Contrary to the regulations laid down in the Ministerialblatt No 45, mining debris no longer is classified into washing mining debris and washing flotation mining debris. Instead, classification of mining debris can be done using parameters for leaching behaviour only. Therefore, a new classification is proposed using the classes ‘washing mining debris I’ to be applied inside and outside of areas containing important water resources and ‘washing mining debris II’ to be applied outside of areas containing important water resources. These two types of washing mining debris differ in their chemical leachate behaviour and their mechanical requirements for dam and cover construction.

     

Ermittlung von Stabilisierungslasten im Holzbau

Calculation of lateral stability loads for timber constructions. Stability loads for lateral bracings are usually calculated by using a simplified method according to the standard for timber constructions. In this article two methods for an accurate calculation of stability loads for lateral bracings will be presented. The first possibility is based on the energy method and can be used for single‐span beams with continuous lateral support. Equations to determine the lateral loads for single‐span beams with constant normal forces or constant bending moments can be determined by using the energy method. Another possibility of verification is the computation of lateral stability loads using the 2^nd order flexural torsion theory for a three‐dimensional loaded beam with discrete lateral supports with any support and load cases by employing the transfer matrix method. The results of both methods will be compared in several examples.     

Einsatz von Stahlfaserbeton im Tunnelbau

Steel Fibre Concrete in Tunnel Constructions Steel fibre concrete is used increasingly for tunnel buildings. Primarily this is based on an intensified acceptance of this composite building material in the building trade, in connection with the positive experiences of individual accomplished tunnel construction projects. The replacement of the conventional reinforcement by steel fibres not only leads to an easement and an acceleration of the operational sequences but also to an improvement of the durability of tunnel constructions. Due to existing normal compressive forces in combination with relatively small bending moments and the statically undetermination of the tunnel shell equivalent solutions to the reinforced concrete are possible.     

Zur Verwendung von Sprinkleranlagen im Wohnungsbau

Employment of sprinkler systems in residential buildings. Current guidelines do not require sprinklers in residential buildings within England and Wales. Research has shown that providing sprinkler system will be able to reduce the number of deaths in fire accidents. It is assumed that in spring 2007 the guidelines within England and Wales will change and sprinkler system will be called for residential buildings over 30 m height. This article discusses the provision of sprinkler system in residential buildings and shows that they could have an important effect on the architectural layout of typical flats.