P 484 - Laser-based labelling and identification processes for steel products

P 482: Design and calculation of lightweight rope drivesThe demands of industry and plant manufacturers with regard to higher lifting loads and lifting heights as well as changed application scenarios are forcing manufacturers of mobile hoists to guarantee ever greater hook loads and ranges with their designs. For the design and dimensioning of rope drums, this ultimately means realising greater rope pull loads and rope storage lengths while at the same time taking changed load collectives into account. Against this background, the further development of calculation methods for the design of rope drums in accordance with load requirements is an ongoing research topic. The present work contributes to the qualification of existing calculation methods for the dimensioning of rope drums. The topic is positioned in the field of multi-layer wound rope drums with a groove system divided into parallel and crossing areas. The problem of this work resulted from experimental investigations on such drum constructions, in which a non-rotationally symmetrical stress distribution in the drum shell was determined, which is not recognised by existing calculation methods. By analysing the contact ratios between the rope windings and describing the loading and unloading mechanisms between the drum and the rope, the formation of a non-rotationally symmetrical winding pressure distribution over the circumference of the drum shell was demonstrated. As an inherent property of the above groove system, this also represents the main cause of the experimentally determined stress differences. The method developed for determining the winding pressure distribution makes it possible to categorise the load differences between the creasing sectors in a practically relevant range. Based on the linear bending theory of the circular cylinder shell, the stresses on the drum shell were determined for the non-rotationally symmetrical load model developed. This analytical method can be used to specify the excess stresses compared to a rotationally symmetrical load distribution, which is the basis of the calculation methods used to date. As an effect of the non-rotationally symmetrical load, the development of additional axial forces in the connection area of the flanged discs was determined and investigated. The results of this work form the basis for a new type of dimensioning of the entire rope drum for the non-rotationally symmetrical loads that occur in practice. Publication: 2004 Authors: Dipl.-Ing. Steffen Otto

P 486 - Investigations on the ductility of composite materials when using high-strength steel and high-strength concrete Authors: J. Hegger, P. Döinghaus, G. Sedlacek, H. Trumpf Publication: 2003 Aim of the research projects are the determination of the load-bearing capacity and ductility of shear connectors in high-strength concrete as well as the development of shear connectors with a sufficient ductility in high strength concrete. Therefore various shear connectors have been tested with Push-Out test. The development of a new Push-Out test specimen enables tests on single headed stud shear connectors and its modification in high-strength concrete. Consequently an accurate analysis of the load-bearing behaviour as well as an efficient check of the various variants is achieved. So that a headed stud shear connector in high-strength concrete will exhibit ductile behaviour while retaining its ultimate load, its application can be modified by enlarging the weld collar, strengthening the connector shaft, e.g. with a sleeve made of metal, using a high-strength base material for fabricating a cold-formed headed stud shear connector (S460) or the arrangement of double connectors as close together as possible due to fabrication. At present the last procedure is the easiest to guaranty an application of headed stud shear connector as ductile shear connectors in high strength concrete. It has absolutely to be renounced on intermediate traverse reinforcement between the studs. The loadbearing capacity of the second stud has to be reduced to 80% of its design value. This possibility is directly applicable for small and medium companies.

P 487: Load application for concrete-lined hollow section composite columns with normal and high-strength concretes In recent years, composite columns made of concrete-lined hollow sections have been increasingly used in multi-storey and high-rise buildings in solid and composite construction. This type of column combines the advantages of steel and concrete in an excellent way in pressure-loaded components and achieves high load-bearing capacities with small cross-sectional dimensions. This type of construction fulfils the demand for ever slimmer components by using additional adjustment profiles, whereby round and square solid core profiles are used in addition to rolled profiles. While the design of such composite columns is adequately regulated at national and European level in DIN 18806-1 and E DIN 18800-5 and in DIN V ENV 1994-1-1, there are no detailed regulations on load application. This applies in particular to the issue of partial surface pressure. This often results in very costly load introduction constructions, which represent a competitive disadvantage of this construction method. Against this background, the aim of this work was to develop design proposals for economical load transfer structures on the basis of suitable experimental investigations. This was done on the basis of 45 column tests and a further 18 slab tests. In 33 column tests, the load-bearing and deformation behaviour of centrally loaded compressed (reinforced and unreinforced) hollow section composite columns was systematically investigated, in which, among other things, the type of load application was varied. A further 12 tests were used to determine the transfer of forces from core profiles via spacer plates. The floor areas between two composite columns were analysed in the slab tests under the aspect of partial area loading due to the direct introduction of forces from the hollow section and a simultaneously applied slab load. As a significant result of the work, a new design concept for cold design has been developed for the load-bearing capacity of the introduction areas of hollow section composite columns. which takes the confinement effect of the steel tube into account to a much greater extent than before. This is independent of the type of load application analysed and provides a consistent transition to the design of compressed columns. It can be seen that the new design proposals are also valid for the partial area loading of concrete under spacer plates of core profiles. In addition, a design approach has been developed for the load-bearing part of the reinforcement, which allows reinforcement to be taken into account if it is only indirectly connected and the column cross-section is only loaded over a partial area at the same time. If the gap dimensions are less than 30 mm and the load is applied over the entire surface, the full load-bearing capacity of the reinforcement can be taken into account in round hollow section composite columns with a concrete lining and a steel tube dimension ratio of d/t < 60, as in the case of a direct connection. The new design methods have already been partially incorporated into Eurocode 4 (prEN 1994-1-1). The comparison with the previously valid verification concepts shows that a significantly more economical design of the force application areas of hollow section composite columns is possible, thus further improving the competitiveness of this type of column. RESEARCH ASSOCIATION FOR STAHLANWENDUNG e.V. Publication: 2004 Authors: Prof. Dr.-Ing. G. Hanswille, Dipl.-Ing. M. Porsch