P 1282 - Use of arc brazing for joining attachments to steel structures subject to high vibrational stresses

P 1281 - Integral and holistic planning of road bridges based on hierarchical models The IntegBridge research project provides a solution for the semi-automated and computer-aided holistic assessment of bridge variants. To this end, algorithms are used for the holistic, life cycle-orientated calculation of the life cycle assessment, economic and macroeconomic effects of a bridge variant. The input data comes from different data sources, which are linked to each other and to construction models using a linked data approach. BIM models can be used as the basis for determining quantities for the quantitative calculations to be carried out. Components of the BIM models are linked with pre-balanced elements and stored in a database so that cost estimates, life cycle assessment effects and construction times are available as input data for the calculations. In order to enable application in different planning phases, the pre-balanced elements are provided in various levels of detail. To map the entire life cycle of a bridge structure, different maintenance strategies can be selected, which are automatically integrated into the model via subsequent elements and represent the various maintenance measures in the life cycle. After being linked to the pre-balanced elements, the BIM models can be transferred via proprietary interfaces (ODBC) or open data exchange formats (IFC) to the IntegBridge software prototype, in which the holistic calculations are carried out. Some additional input data must be defined there that cannot be provided in the components. These are, for example, the traffic routes, the discount rate, the maintenance strategy to be used and information on the traffic load. The construction-related costs, life cycle assessment effects and economic costs of a variant can then be calculated. Economic costs are mainly caused by construction-related traffic disruptions and the resulting time lost by road users. A deterministic queueing model is stored in the algorithm for the calculation. The workflow developed (see Figure 1) makes it possible to evaluate bridge variants holistically. In this way, different bridge variants can be compared with each other at an early stage and the preferred variant can be continuously optimised in terms of its economic, ecological and macroeconomic effects by means of an analysis accompanying the planning process. The aim is to realise the most advantageous bridge variant for the specific location rather than the cheapest in terms of construction costs. Authors: M. Müller, Dr.-Ing. T. Zinke, Dipl.-Ing. M. Hermann, Prof. Dr.-Ing. T. Ummenhofer

P 1284 - Investigations into the suitability of corrugated board as an ecological core material for sandwich elements This project investigated the suitability of corrugated board as an alternative core material for sandwich elements for cladding roof and wall surfaces. For this purpose, the most important fundamentals of paper and corrugated board on the one hand and sandwich construction on the other were compiled. Based on this, a suitable material model was found and the elastic material parameters and strengths were determined for a total of 10 different types of corrugated board. The tests to determine the elastic material model could not be statistically analysed due to the insufficient number of tests. However, despite some large scatter, the tests allow a basic evaluation of the load-bearing behaviour of corrugated board. In bending tests on sandwich samples in the form of beams and components, the composite load-bearing behaviour was investigated for four selected types of corrugated board and three different core orientations. The influence of the inhomogeneity of a core made of prefabricated lamellas was also analysed. The bending tests of the elements with the weakest core orientation, in which the flat papers lie parallel to the cover layers of the components, resulted in load-bearing properties comparable to those of sandwich elements with conventional core materials when using high-quality corrugated cardboard. For the elements of the other two core orientations, the flat papers are in the XZ plane of the sandwich elements. These provide such good support for the surface layers to prevent them from moving out of their plane that even steels with yield strengths of up to 500 N/mm² can be stressed to the point of yielding. Similar to conventional materials, the elements with the weakest core orientation exhibit such high creep coefficients that a planned continuous loading of elements with flat surface layers is not compatible with the serviceability requirements. The other element types, on the other hand, showed such small time-dependent increases in deformation that it may be possible to open up further areas of application for these elements with planned continuous loading. Investigations into the thermal conductivity of selected boards showed that the best thermal insulation properties were achieved in the core orientation of the type 1 tested. The insulating properties are close to those of mineral wool elements. For elements of types 2 and 3, the measurements showed similar thermal conductivities for both types. However, these are so high that the use of this type of element for heated residential buildings would hardly be feasible in practical construction terms. Investigations into moisture protection have shown that condensation cannot form in a sealed core. Long-term experiments on components with one side edge each, which was not protected and exposed to high ambient humidity, have shown that moisture from the air slowly penetrates into an element. Element sides that are unprotected from the environment should therefore be avoided. Publication: January 2021 Authors: Prof. Dr.-Ing. J. Lange, Dipl.-Ing. A. von der Heyden

P 1285 - Integral solutions for energy-plus buildings 2.0 in lightweight steel construction Until now, research into the sustainability and energy efficiency of buildings has mostly focussed on residential and administrative buildings. Industrial and commercial buildings have received little attention. This type of building also falls under the EU's Energy Efficiency Directive 2012/27/EU and must be operated in an energy-neutral manner in future. Yet these buildings in particular offer a great deal of potential for saving CO2, as they combine large volumes and surfaces with an efficient, industrialised construction method. In the research project, a holistic approach to the planning and construction of commercial buildings is being developed with the aim of constructing grid-friendly plus-energy buildings and providing corresponding planning recommendations. The possibilities of operating heating and cooling on the basis of renewable energy and generating both electrical and thermal energy on site are being analysed. Based on a comprehensive analysis of the building typology of a commercial building with an office extension, design recommendations are developed and a model building is planned. Steel-based components are being developed for this, which are being analysed in the laboratory and in long-term tests to determine their performance and interaction in a TGA concept. Radiation-based surface heating and cooling elements using thermally activated trapezoidal profiles proved to be a sustainable solution for transferring heat to the room in terms of performance, efficiency and design. The regenerative energy used for this can be obtained using the innovative steel energy piles analysed. Compared to conventional systems, clear advantages in terms of performance were demonstrated. The invisible and façade-integrated solar collectors developed can also be used as a further regenerative source. This can also be used to prevent undercooling or overheating of the ground. The investigated façade application of organic photovoltaics can help to supplement the electricity yield from a classic silicon-based system on the roof. As part of the project, it was shown that the technologies described can be used efficiently and that plus-energy buildings in lightweight steel construction are possible. Publication: 2021 Authors: Prof. Dr.-Ing. M. Kuhnhenne, Dipl.-Ing. V. Reger, Prof. Dr.-Ing. H. Hachul, Prof. Dr.-Ing. Bernd Döring, M. Sc. T. Blanke

P 1287 - Concrete-filled hollow section composite columns for multi-storey buildings - Innovation and design Composite columns are used in building and industrial construction due to their many favourable properties. On the one hand, columns with smaller cross-sectional dimensions can be realised with high load-bearing capacities at the same time. On the other hand, high fire resistances can be realised without additional fire protection measures. This is made possible by the targeted combination of the material properties of steel and concrete, in particular the high strength and rigidity of steel and the low thermal conductivity of concrete. Concrete-filled hollow section composite columns using high-performance materials have the potential to exhibit even greater load-bearing resistance or slimmer column cross-sections and thus open up further markets. As part of the FOSTA research project Concrete-filled hollow section composite columns for multi-storey buildings Innovation and design (IGF project no.: 19677), the stability behaviour of hollow section composite columns was investigated using experimental, numerical and analytical methods. The current version of Eurocode 4, Part 1-1 Design of composite steel and concrete structures contains verification methods for various types of composite columns. However, there are currently no standardised simplified verification methods for standard temperatures and fire design for concrete-filled hollow section composite columns with a solid steel core and double hollow section composite columns. This is where the research project came in. The experimental investigations comprised a total of 24 column tests with different cross-sections, dimensions, steel grades and concrete strengths. So-called stub column tests were carried out to experimentally analyse the cross-section capacity. In addition, one-storey (4m) and two-storey (8m) columns with practical cross-sectional dimensions were tested in order to evaluate the use of high-strength materials (structural steel S770 and S890 as well as concrete C100/115) in practice. Based on the ultimate load tests at normal temperature, a numerical model was developed which implies experimental material properties, composite effect, geometric imperfections and residual stresses. Numerical simulations and parameter studies were used to describe and investigate the basic structural-mechanical behaviour of the composite column cross-sections. In addition, an FE model for fire simulations was developed, validated using external tests and simulation studies on fire behaviour under a standard temperature-time curve with utilisation levels relevant to construction practice were carried out. Based on experimental and numerical results, a simplified analytical model was developed for verification in accordance with Eurocode 4. In addition, the scientific basis for a simplified verification procedure for the design of innovative concrete-filled hollow section composite columns in the event of fire was developed. Publication: 2021 Authors: Prof. Dr sc. techn. habil. M. Knobloch, M.Sc. P. Schurgacz