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Fast‐charging station Leipzig – the floating roof on a computer‐generated endless support For a fast‐charging station at the production site of a sports car manufacturer, a roof was to be developed that would transport the image of the brand in addition to I function as weather protection. The existing technical infrastructure, i. e., power lines that could not be built over and movement and maintenance spaces for the charging columns, only allowed for a few and, above all, irregular support points and support positions. The design process results in a seemingly floating roof whose cladding is modelled on an aerofoil supported on a single endless column. The infinite support Spline, iconographically analogous to an initially simple appearing bent‐up paper clip, ensures both the clamping of the cantilevered roof and the global reinforcement through the spatial support positions and inclinations. The geometry was developed using an evolutionary optimisation algorithm with the most outstanding efficiency while complying with the given geometric restrictions. Within the parametric structural model, in addition to the control and analysis of the static performance, the geometric implementation of the milled circular arcs at the head and foot points was also carried out. The entire process, from the development and variant study to the analysis and documentation to the production, thus took place in a closed digital process chain. Therefore, it was possible to achieve the design goal of contrasting a flat roof and a filigree support structure. [ABSTRACT FROM AUTHOR]

3DWelding – additive fabrication of structural steel elements This paper investigates the possibilities of robotic 3D printing with steel (WAAM – Wire and Arc Additive Manufacturing) in the construction industry. The aim of the project team is to develop a stable and economical manufacturing process for customized steel elements. Thus, the influence of different process parameters such as wire feed rate and travel speed on the weld shape and build‐up rate as well as on the material properties will be explained and a parameter window with stable, verified parameter sets will be defined for each material used. Three different filler metals (G 2Si1, G 3Si1, G 4Si1) are tested in terms of their strength and stiffness, with particular attention paid to the joining area between substrate and welded structure. For this purpose, test methods for testing additively manufactured components, especially for shear capacity, have been newly developed. As a proof of concept, an exemplary application is shown and the load‐bearing capacity of this connection is investigated in different configurations. [ABSTRACT FROM AUTHOR]

Universal high‐performance columns made of high‐strength steels without welding In recent years, steel‐concrete composite columns made of normal‐strength steels are seldom used owing to the economic and technological advantages of precast reinforced concrete columns. Though, the use of high‐strength structural steels bears high potential for the efficient production of composite columns with excellent structural performance that are economically competitive to precast concrete columns, there are currently major obstacles to use of the ultra‐high‐strength steels (UHSS) in Germany. Hollow section composite columns with embedded high strength steel core without welded connections provide an opportunity to regain lost market share. A research project, funded by the AiF (Arbeitsgemeinschaft industrieller Forschungsvereinigungen), is intended to explore the potential of UHSS composite columns by experimental and theoretical investigations. The present paper demonstrates the concept of such composite columns with UHSS and gives first exciting insights into the research results. In addition to column tests under ambient and fire conditions, small scale tests are necessary to investigate various influencing factors and to create the basis for new and easy to use design and construction principles that allow efficient application. [ABSTRACT FROM AUTHOR]

Durability and robustness of bolted joints for crane runway beams The paper deals with selected topics related to bolted connections in crane runway girders. First, the behaviour of the connection during tightening and under external loading is described. The significance of the preload for the bolted connection is discussed. The mechanisms underlying losses of preload and securing methods to counteract them are introduced. Subsequently, these securing methods are linked to typical crane runway connections. The paper concludes with considerations for the inspection of the connections in the event of installation and operation of the crane system. [ABSTRACT FROM AUTHOR]

Utilization of fibre placements in flexible light weight structures For the World Expo 2020 in Dubai, Werner Sobek developed innovative shading systems that connect all the country pavilions on the exhibition grounds. These structures span an area of around 96,000 m2. Three different shading systems were developed on the basic principle of a wide‐span steel frame structure. This paper presents one of the three shading systems, which was designed with a fibre scrim. It was adapted to the harsh climatic conditions of the site by specifically integrating innovations in filament scrim technology into the design. An important design goal was to provide shading and air circulation to improve the microclimate in the public space. The ambient temperature under the shading elements was thus to be naturally reduced by 5 °K. Other important objectives were to minimise CO2 emissions and grey energy as well as to design and build in a way that is suitable for recycling. [ABSTRACT FROM AUTHOR]

Design of the new Rhine bridge Duisburg‐Neuenkamp Due to the deficient condition of the existing Rhine bridge Duisburg‐Neuenkamp as well as due to the increasing traffic load, the realization of an efficient Rhine crossing and the eight‐lane expansion of the highway A 40 between the Duisburg‐Homberg junction and the Duisburg interchange is imperative and therefore designated as an essential part of the project 220 in the Federal Transport Infrastructure Plan 2030 with planning rights. This technical paper deals with the special features of the design of the new bridge over the Rhine. It deals also with the design‐determining boundary conditions up to the design and structural design of the bridge structures and presents the construction process. [ABSTRACT FROM AUTHOR]

Lifetime estimation of hollow sections joints under variable amplitude loading Hollow sections are often used for light weight constructions for cranes, for offshore structures as well as for bus constructions or in agricultural machines. Normally these structures are built up as truss or frame constructions and are typically subjected to very high variable amplitude loadings. The linear damage accumulation acc. to Palmgren‐Miner serves the basis for the structural durability design, which, however, also have many weaknesses due to the simple handling of this rule. For instance, influence factors like the load sequence, occurring overloads and welding residual stresses cannot be taken into account for the lifetime estimation. Within the framework of the FOSTA research project P 1195, extensive experimental tests were carried out on typical welded hollow section joints from the application area of crane constructions and bus constructions. A summary of the results obtained in the field of the application area of crane constructions is presented in this paper. [ABSTRACT FROM AUTHOR]

3D printed columns with exceptional geometry Wire Arc Additive Manufacturing (WAAM) is a welding process used to build up three‐dimensional structures in steel. Like other Additive Manufacturing technologies, it allows for geometrically‐exceptional structures to be fabricated which are otherwise unfeasible or very expensive to manufacture using traditional methods. This paper presents an integrated design approach to the use of WAAM in the context of large‐scaled applications, focusing on columns with exceptional geometric complexity. It combines material behaviour and process parameter research, with the aim of providing a digital tool to design and print structures using WAAM. To achieve the desired geometries, necessary welding parameters are stored and applied to a rudimentary digital twin model. This is complimented by multiple process‐control checks, which are implemented during the printing process to ensure that an object is generated as planned. Finally, the structures are manufactured and are subjected to a critical evaluation in order to identify the possible future potential. The challenge of combining geometric complexity with manufacturing for large scale represents a next step in the integration of WAAM in steel constructions. [ABSTRACT FROM AUTHOR]

During an earthquake, steel frame buildings with bracings are prone to high absolute floor acceleration demands, thereby causing damage to acceleration‐sensitive non‐structural elements and building content. Inelastic deformations in steel bracings and/or their end connections often necessitate the use of capacity design rules to meet the life safety requirements established by seismic design standards. This paper presents an alternative steel frame building configuration where energy dissipation is mostly achieved through friction dampers acting as dissipative connectors between the floor diaphragms and the steel frame(s) with bracings. The dampers consist of friction pads made from composite materials which are not susceptible to galvanic corrosion. Physical experiments suggest that the friction pads are effective in dissipating the seismic energy through friction. Nonlinear response history analyses of a prototype 6‐storey steel frame building featuring friction dampers as dissipative floor connectors demonstrate that a) higher mode effects are mitigated; b) capacity‐design in the steel frame(s) with bracings is not imperative to ensure a uniform lateral drift distribution; and c) the seismic response variability in storey‐based engineering demand parameters is reduced remarkably compared with that of the conventional counterpart with rigid diaphragms. All‐in‐all, the alternative building configuration has high potential to minimize earthquake‐induced repairs over a building's service life. [ABSTRACT FROM AUTHOR]

Seismic resistant buildings with dissipative elements made of high strength steel This paper presents the application of high strength steel S700MC in dissipative elements of seismic resistant FUSEIS structures. The results of large scale cyclic tests are presented and are used for the development and calibration of nonlinear numerical models. The experimental results indicate high ductility, although reduced compared to those from conventional steels. The seismic design of buildings with such elements is illustrated in two case‐studies, first by application of practice‐oriented linear methods. Subsequently, their seismic performance is checked by nonlinear static and dynamic analyses. The investigations show that high strength steel may be used in dissipative elements of seismic resistant buildings. However, its advantages come into effect for stiff bracing systems where serviceability criteria do not prevail in design and dissipation at moderate deformations is demanded. [ABSTRACT FROM AUTHOR]

Resource and emission efficiency in bridge construction using the example of the Leverkusen campus bridge The construction industry is a major contributor to the global emissions of climate‐affecting CO2. Solutions on the track to carbon‐neutral construction and operation can only be achieved through a holistic approach that includes the use of resources. The approach spans from questions about the necessity and size of a building (build less), through a planned re‐use of components and the reduction of material in the design process (build clever), to the selection of materials based on their specific grey emissions (build efficiently) in a tight circulation system (minimise waste). A uniform assessment of the efficiency of resources and emissions for bridge structures is currently not possible due to the lack of internationally coordinated regulations. Using the example of the Campusbrücke in Opladen, Leverkusen, a footbridge built in 2013, the paper explores the different practical approaches that have contributed to a reduction of emissions and used resources. Using a Life Cycle Analysis method (LCA), the selected structure is compared to an alternative design. [ABSTRACT FROM AUTHOR]

On crane runway brackets in steel structures – fatigue assessment of load introduction into the bracket web Crane runway brackets are typical crane runway supports in steel structures and fall in the scope of design standard EN 1993‐6. The crane runway brackets are exposed to cyclic stressing because of crane action and, therefore, they need sufficient fatigue resistance. In the past, neither a fatigue evaluation had been performed, nor particular guidance was given by the specifications for an appropriate design in terms of fatigue. This paper deals with the fatigue loading of crane runway brackets and describes structural boundary conditions under which a particular fatigue verification for the load introduction into the bracket web is allowed to be omitted. [ABSTRACT FROM AUTHOR]

Atrium roof and steel spiral stairs at the scientific building D‐BSSE of ETH Zürich in Basel On the campus of the University of Basel an outstanding scientific building ist currently being erected. It will be the future home of the Department of Biosystems Science and Engineering (D‐BSSE) of ETH Zürich. The planning process started in 2013 following an architectural design competition. Construction began in 2018 and is expected to be completed in 2022. Key element of the building layout is a central atrium. It is covered by an elegant glass roof and therefore floodeded with light. The desired brightness could only be achieved by a gridshell. Its shape is the result of a form‐finding process. The atrium's footprint resembles a triangle with rounded corners. Its maximum dimensions are about 20 m × 35 m. Two iconic spiral stairs are located opposite each other in two corners of the atrium. They connect two or three floor levels respectively and span freely between the floor slabs. Those three steel structures, which dominate the atrium's internal space, are the result of a close collaboration between the architect and the structural engineer. This design process, the technical challenges in design and construction are the subject of this paper. [ABSTRACT FROM AUTHOR]

Warping springs and their potential for stiffening i‐beams at risk of lateral torsional buckling – a case study Warping springs offer the possibility to stiffen drill‐soft I‐beams under torsion by means of the so‐called drill coupling. In practice, lateral torsional buckling, a complex stability failure, is often decisive for the design of slender I‐beams. The stiffening of I‐beams against torsion with warping springs also has a positive influence on the lateral torsional buckling resistance. For example, hollow warping springs welded into the beam can stiffen the system to such an extent that the choice of larger beam sections can be avoided. Starting from warping springs in the form of U‐profiles, their geometry can be optimised in terms of material savings without the overall system experiencing significant losses in stiffness compared to the full U‐profiles. In this respect, additive manufacturing represents an alternative to the conventional production of warping springs. In addition to an overview of warping springs, this paper shows by means of a case study to what extent the lateral torsional buckling of a drill‐soft single‐span I‐beam can be increased by warping springs. The optimisation of the warping spring geometry and its effect on the stability of the beam is also considered. [ABSTRACT FROM AUTHOR]