Prof. Dipl.-Ing. Dr. Norbert Randl  Martin Steiner Dipl.-Ing. 《Beton- und Stahlbetonbau》2020,115(5):375-384

High strength concrete overlays – Part 2: Member tests Small scale and member tests with different specimen geometries and test setups were performed to investigate the adhesive bond along interfaces between normal strength concrete and high strength overlay. Part 1 reports about the small scale tests, while this part 2 focuses on slab tests. Apart from standard application of normal and high strength concrete layers, two slabs were subject to cyclic loading during casting the concrete overlay. In general, also the member tests confirm the improvement of the bond properties with the high strength concrete overlay. All slabs with normal strength overlay concrete depicted some limited degradation along the shear interface in the tests, while members reinforced with high strength concrete showed hardly any degradation along the joint except for the slabs that underwent cyclic loading during overlay casting.  相似文献   

    

Ulli Heinlein  Prof. Dr.-Ing. Thomas Freimann  Serdar Bilgin  Sebastian Filusch Dipl.-Ing.  Dr.-Ing. Lars Meyer  Dr.-Ing. Knut Herrmann 《Beton- und Stahlbetonbau》2020,115(9):671-683

Pre-applied bonded membranes – latest research and practical findings Pre-applied bonded membranes have been used in Germany for several years as additional water-side sealing layers on water-impermeable concrete structures. They are intended to increase the reliability level of the waterproofing or are used as planned sealing measure for separation cracks. But planning and application are not yet subject to any regulations. Pre-applied bonded membranes are neither regarded as independent waterproofing layer nor are they regulated in combination with water impermeable concrete structures. Also, the testing of products is not yet subject to uniform principles. For this reason, fundamental properties of the pre-applied bonded membranes were determined within the project presented hereafter. Besides the determination of the hitherto existing practical experience with pre-applied membranes and the classification in the existing regulations, properties were determined and suitable test procedures were identified. These were used to determine the basic properties of ten pre-applied products, such as the protection against lateral water migration or the water impermeability of the seams. In addition, practical recommendations and quality assurance measures could be formulated.  相似文献   

    

Prof. Dr.-Ing. Klaus Bollinger  Prof. Dipl.-Ing. Manfred Grohmann 《Beton- und Stahlbetonbau》2020,115(8):617-625

Concrete: material and design in practice Stefan Polónyi was one of our role models when we founded our engineering office and we still feel motivated and inspired by him. His holistic approach has shaped our self-image as structural engineers and thus has a lasting influence on the development of our office. Against this background, we would like to use some selected projects to reconstruct the development of our work. In connection with this, we would also like to document the progress in digital planning and show how the ongoing process of digitalization has changed the collaboration between architects and civil engineers in the direction of Stefan Polónyi's way of thinking.  相似文献   

    

Prof. Dr. techn. Andreas Taras  Armin Kager Dipl.-Ing.  Dipl.-Ing. Dr. techn. Dieter Theiner  Dipl.-Ing. Dr. Valentina Cavedon 《Stahlbau》2020,89(5):424-438

Assessment of existing steel penstocks in hydropower plants – strategies in the context of the installations in South Tyrol Steel penstocks carry water over large distances and often steep changes of altitude from the water catchment to the turbines in the powerhouse. As structural elements and – simultaneously – fluid transport lines, they represent steel structural elements that are loaded in a very high and complex manner. For the operators of hydropower plants, the assessment of the structural condition and the associated risks of steel penstocks thus represents one of the crucial steps needed to obtain, renew and maintain an operating concession from public authorities. Assessments of this type were carried out systematically over the course of the last few years for the many hydropower plants in the Italian Autonomous Province of Bolzano – South Tyrol, due to their particular significance for the energy supply of the region and the advanced service life of many plants. The assessment of the structural health and safety of existing, ageing steel penstocks thereby requires expertise drawn from various disciplines and reports from literature, due to the fact that no encompassing, dedicated standard or code of practice for this task is currently available that fully reflects the current state of the art in the reliability and strength of steel structures for this type of components. In fact, steel penstocks in hydropower plants share some features with civil steelwork structures and others with pressure vessels and components. Non-destructive testing techniques as well as advanced, non-linear numerical calculations thus play a significant part. This article gives a summary of the methods and techniques recently applied for the assessment of steel penstocks in South Tyrol.  相似文献   

    

Dipl.-Ing. Dr.techn. Michael Reiterer  Univ.-Prof. Dr.-Ing. habil. Natalie Stranghöner  Dr.-Ing. Dominik Jungbluth 《Stahlbau》2020,89(2):164-178

Experimental investigation on the preload behaviour of noise barrier steel post fastenings on structures In addition to part 1 – fatigue behaviour in the present article the preload behaviour of noise barrier steel post fastenings on structures is experimentally studied and valuated. In a first indicative pre-test altogether four bolted connections were preloaded and released three times consecutively with a defined level of tightening torque and in every test the solid lubricant Molykote 1000 was applied. The tested threaded bolts and screw nuts are made of stainless steel A4-80 of M20 dimension. Beside the investigation of the preload behaviour of the bolted connection the pre-tests were performed to study the influence of different washer types to the resulting preload level within the threaded bolts. Due to the fact that bolted connections made of stainless steel are currently not regulated in civil engineering standards, it was decided to perform additional experimental tests in term of a tightening procedure test on the calibrated tightening-torque testing machine facility for mechanical fasteners of the Institute for Metal and Light Weight Structures of University of Duisburg-Essen. On the basis of the performed tightening-torque tests considering threaded bolts of M16 and M20 dimension made of stainless steel in combination with stainless steel wedge-lock washers and solid lubricant a tightening procedure for preloading threaded bolts made of stainless steel was defined.  相似文献   

    

Nadia Gremer Dipl.-Ing.  Univ.Prof. Dipl.-Ing. Dr. techn. Christoph Adam  Dipl.-Ing. Dr. techn. Lukas Moschen  Ricardo A. Medina 《Stahlbau》2020,89(1):4-15

Influence of damping modelling on the acceleration response of an earthquake-excited steel frame structure As part of a case study, this paper deals with the effect of different damping approaches on the computed acceleration response of a planar, regular, elastic steel frame under earthquake excitation. In this study, not only the amplification of the horizontal ground acceleration, as is usual in earthquake engineering, but also the amplification of the vertical ground acceleration is considered. It is shown that Rayleigh damping used in accordance with engineering and scientific practice, leads to a minor amplification of the vertical ground acceleration only because damping of the vertical modes is too large compared to the lateral modes. This explains the erroneous assumption that the amplification of the vertical ground acceleration is negligible. In contrast, Rayleigh damping based on effective vertical mass participation overestimates both horizontal and vertical structural acceleration. The implementation of the inherent damping in the computational model in the form of modal damping, however, leads to a realistic computational prediction of the acceleration response in both directions.  相似文献   

    

Prof. Dr.-Ing. Karsten Geißler  Gregor Gebert Dipl.-Ing. 《Stahlbau》2020,89(2):148-163

Design, construction and calculation specifications of current large composite bridges At the next few years numerous large bridges in the network of federal highways will have to be replaced. At structural design the composite deck bridges are often preferred because of advantages by prefabrication and quick installation. At the present contribution current developments of these composite bridges are discussed with special regard to structural design including the cross-sectional design as well as construction details. Finally some current DEGES projects are presented  相似文献   

    

Markus Hochmuth Dipl.-Ing.  Thi Nguyen  Marco Häußler Dipl.-Ing. 《Bautechnik》2020,97(2):100-106

Innovative and modern planning methods in bridge construction Building Information Modeling (BIM) offers the opportunity to realize modern large-scale projects on schedule and within budget during the planning, construction and operation of a building. Because consistent data throughout the entire process can increase the efficiency and quality of a building. Bridge construction in particular poses a special challenge here, since despite recurring typology, the dependencies of the individual components for routing make each structure individual. This problem can be solved by parameterizing the building models. In concrete terms, this means that each structural element is given at least one dependency for the routing of the road/railway above or below the bridge on the basis of the space curve. If the route changes, the structure will also adapt. This permanent connection also allows quantities, component lists and 2-D plans to be adapted automatically. Dependencies of the components on each other or on the terrain model are also possible. This means that collisions within the building can be avoided during the planning phase. Intelligent data models can help to increase the quality, efficiency and productivity in the realisation of project-specific buildings.  相似文献   

    

Daniel Konopka Dipl.-Ing.  Josef Stöcklein Dipl.-Ing.  Prof. Dr.-Ing. habil. Michael Kaliske 《Bautechnik》2020,97(10):708-716

New numeric simulation for old wooden structures Wood is a construction material with a long tradition and a wide area of application. This contribution gives insight into the numerical simulation of historical wooden cultural heritage objects by means of the Finite Element Method. The material properties of wood are mutually non-linear, scale-, direction-, climate- and time-dependent. Within wood or timber structures, also glued joints, varnishes and veneers contribute to the climate-dependent structural behaviour. The influence of the material, the mechanical and the climate loadings on the time-dependent structural behaviour and the approaches of the numerical simulation for the evaluation of the wooden structureś load-bearing behaviour are represented by current models on structural examples. This contribution has been presented on 18 October 2019 at the “23. Dresdner Baustatik Seminar“.  相似文献   

    

Konrad Westermann Dipl.-Ing.  Dr.-Ing. Jörg Meier  Laurent Pitteloud Dipl.-Ing. ETH 《Bautechnik》2020,97(12):878-885

Excavation pit and foundation of a research center During planning and construction of the excavation pit and foundation of the new research center of Roche in Basel (Switzerland), several challenges have been solved by applying automated procedures and digital methods in civil engineering. The project is located in an urban area on the periphery of the industrial and research site of Roche with sensitive neighbouring buildings. Above ground, the research center consists of four buildings with heights increasing from west to east between 18 and 115 m. These four buildings share a 140 m long, 70 m wide and 22 m deep six-storey basement. At site, a diaphragm wall was constructed in the 1970s for an excavation pit with the same dimensions. This 45-year-old diaphragm wall has been reactivated as excavation pit support for cost- and time-saving reasons and the existing basement had to be replaced by a new one. The existing diaphragm wall was secured with up to five anchor layers to withstand the earth pressure and the 12 m high water pressure in the highly permeable subsoil. The foundation was designed as a combined piled raft foundation (CPRF) with a 1.5 m thick raft and 178 heavy-duty bored piles. The heavy-duty bored piles with a diameter of 120 cm and lengths of 10 to 28 m were constructed 12 m below groundwater level from the bottom of the excavation pit. By automating the CPRF iteration procedure the planning expenses and the construction costs were significantly reduced.  相似文献