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Karlsruhe, Germany

Konyukhov A.,Karlsruhe Institute of Technology | Lorenz C.,Ingenieurgruppe BAUEN | Schweizerhof K.,Karlsruhe Institute of Technology
Computational Mechanics | Year: 2015

The finite cell method (FCM) provides a method for the computation of structures which can be described as a mixture of high-order FEM and a special integration technique. The method is one of the novel computational methods and is highly developed within the last decade. One of the major problems of FCM is the description of boundary conditions inside cells as well as in sub-cells. And a completely open problem is the description of contact. Therefore, the motivation of the current work is to develop a set of computational contact mechanics approaches which will be effective for the finite element cell method. Thus, for the FCM method we are developing and testing hereby focusing on the Hertz problem the following algorithms: direct integration in the cell method, allowing the fastest implementation, but suffering from numerical artifacts such as the “stamp effect”; the most efficient scheme concerning approximation properties the cell-surface-to-analytical-surface contact element designed for contact with rigid bodies leading to cell-wisely contact elements; and finally the discrete-cell-to-cell contact approach based on the finite discrete method. All developed methods are carefully verified with the analytical Hertz solution. The cell subdivisions, the order of the shape functions as well as the selection of the classes for shape functions are investigated for all developed contact approaches. This analysis allows to choose the most robust approach depending on the needs of the user such as correct representation of the stresses, or only satisfaction of geometrical non-penetration conditions. © 2015 Springer-Verlag Berlin Heidelberg Source

The use of pre-fabricated concrete elements has special advantages for the building industry. In this paper the butt-joint connection of prefabricated reinforced concrete columns under high horizontal stresses is focused. A calculation example demonstrates the representative loading cases and the shear design of a butt-jointed concrete column with a steel plate. Additionally it is differentiated under which situations not the shear bearing capacity of the joint but of the concrete element is decisive for the design. By determining an allowable maximum ratio HEd/NEdthe critical loading scenarios are shown and an alternative design model for very smooth column joints is presented and evaluated in an user-friendly chart. Copyright © 2013 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin. Source

Egner R.,Ingenieurgruppe BAUEN | Heyde S.,Krone Ingenieure GmbH | Laumann J.,Laumann U. P. Beratende Ingenieure PartmbB | Prokop I.,Verband Beratender Ingenieure VBI
Stahlbau | Year: 2015

Proposals for a user-friendly amendment suited for practice of the general rules and rules for buildings of steel structures (EN 1993 Part 1-1). The Eurocodes will be revised in the European Committee for Standardization (CEN), Technical Committee (TC) 250, up to 2020. In preparation on the eurocode amendment engaged engineers have examined the most frequently used parts of the Eurocode 3 within the Initiative Practice-oriented Rules in Building Construction (PRB). The EN 1993-1-1 belongs to the examined parts as a basis part for the steel construction. With the aim to improve the user-friendliness and ease of use of EN 1993- 1-1 the existing norm was analysed and proposals were compiled for the European amendment. The analyses show that lots of the texts can be shortened without loss of information. Restructuring can enhance comprehensiveness and ease of use of the general rules and rules for buildings of steel structures considerably. © 2015 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin. Source

The dynamic properties of bell towers, and especially their resonance frequency, are often characterised by a non-linear relationship between the effect of horizontal forces that are released by the bells and the dynamic reactions of the building. This is particularly true if small resonance intervals cause a considerable dynamic increase of the effective forces. In metrological analyses of the dynamic properties of bell towers, it is mandatory to implement methods of oscillation excitation that are adapted to individual cases and allow for the detection of non-linear effects. It is shown by the examples of a few problematic cases that the use of a frequency-controlled shaker is usually required for proper analysis as a prerequisite for cost effective repair tasks. Finally, guidelines for methods of oscillation excitement, suitable for individual cases, are provided. © 2011 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin. Source

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