02 Fakultät Bau- und Umweltingenieurwissenschaften
Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/3
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Item Open Access Editorial - transformable structures and envelopes in architecture and civil engineering(2023) Phocas, Marios C.; Matheou, MariaItem Open Access A novel transformation model for deployable scissor-hinge structures(2010) Akgün, Yenal; Sobek, Werner (Prof. Dr.-Ing. Dr.-Ing. E.h.)Primary objective of this dissertation is to propose a novel analytical design and implementation framework for deployable scissor-hinge structures which can offer a wide range of form flexibility. When the current research on this subject is investigated, it can be observed that most of the deployable and transformable structures in the literature have predefined open and closed body forms; and transformations occur between these two forms by using one of the various transformation types such as sliding, deploying, and folding. During these transformation processes, although some parts of these structures do move, rotate or slide, the general shape of the structure remains stable. Thus, these examples are insufficient to constitute real form flexibility. To alleviate this deficiency found in the literature, this dissertation proposes a novel transformable scissor-hinge structure which can transform between rectilinear geometries and double curved forms. The key point of this novel structure is the modified scissor-like element (M-SLE). With the development of this element, it becomes possible to transform the geometry of the whole system without changing the span length. In the dissertation, dimensional properties, transformation capabilities, geometric, kinematic and static analysis of this novel element and the whole proposed scissor-hinge structure are thoroughly examined and discussed. During the research, simulation and modeling have been used as the main research methods. The proposed scissor-hinge structure has been developed by preparing computer simulations, producing prototypes and investigating the behavior of the structures in these media by several kinematic and structural analyses.Item Open Access Branding im Industriebau am Beispiel der Automobilfertigung : eine gebäudetypologische Betrachtung(2009) Schönbeck, Dewi; Sobek, Werner (Prof. Dr.-Ing.)In der Automobilbranche nimmt das so genannte Branding zur Schaffung einer unverwechselbaren Markenidentität einen immer höheren Stellenwert ein. Dabei stellt auch die Architektur eines Unternehmens ein Medium zur Vermittlung von Markenwerten dar, das ein dreidimensionales, räumlich erfahrbares Markenerlebnis bietet. Gerade beim Lifestyle-Produkt Auto tritt die ursprüngliche Transportfunktion mehr und mehr in den Hintergrund. Vielmehr will der Kunde damit auch Lebensphantasien, sinnliche Werte und Sozialprestige einkaufen. Umso mehr kann deshalb die Unternehmensarchitektur dieses diffuse Kundenverlangen mit im eigentlichen Sinne begreifbaren Werten ästhetisch umsetzen und damit zu einer innigeren Kundenbindung entscheidend beitragen. Längst haben die Automobilhersteller die Architektur als Medium zur Vermittlung ihrer Markenwerte entdeckt. Beispiele wie der BMW "Vierzylinder" in München, die Autostadt Wolfsburg, das Mercedes-Benz Museum in Stuttgart sowie zahlreiche spektakuläre Mikroarchitekturen im Messebau zeigen, dass das Markenerlebnis durch Architekturerfahrung im Wettbewerb um den Kunden unverzichtbar geworden ist. Der bewusste Einsatz von Markenarchitektur im Industriebau ist jedoch nach wie vor eher ungewöhnlich und nur an vereinzelten Bauten realisiert worden. Pilotprojekte wie die Gläserne Manufaktur in Dresden oder der Zentralbau des BMW Werks in Leipzig geben eine Tendenz zu einer vollkommen neuartigen Gebäudeform im Industriebau vor. Die Automobilfabrik ist bei diesen Projektbeispielen nicht mehr als reine Produktionsstätte zu sehen, in der Mensch und Maschine möglichst effizient zusammenarbeiten, sondern bezieht den Kunden emotional in den Produktionsprozess mit ein. Diese Entwicklung hat zur Konsequenz, dass die Fabrik in Zukunft nicht mehr nur als reine Produktionsstätte fungiert, sondern gleichzeitig als Kunden-Erlebniszentrum gestaltet werden kann. Durch die theoretische Analyse der veränderten architektonischen Anforderungen sowie der Untersuchung von realisierten Beispielen wird in dieser Arbeit eine neuartige, funktionshybride Gebäudetypologie definiert und entsprechende Planungskriterien abgeleitet.Item Open Access Integration of LCA in the planning phases of adaptive buildings(2019) Schlegl, Friederike; Honold, Clemens; Leistner, Sophia; Albrecht, Stefan; Roth, Daniel; Haase, Walter; Leistner, Philip; Binz, Hansgeorg; Sobek, WernerThe high consumption of resources in the building industry requires a significant reduction of material in buildings and consequently a reduction of emissions over all phases of the life cycle. This is the aim of the Collaborative Research Centre 1244 Adaptive Skins and Structures for the Built Environment of Tomorrow, funded by the German Research Foundation (DFG), which addresses research on the development and integration of adaptive systems in building structures and skins. New approaches in building planning are required for the implementation of adaptive buildings. Therefore, a multidisciplinary team from various fields such as architecture, civil and mechanical engineering, and system dynamics is necessary. The environmental impacts of the whole life cycle have to be considered for an integral planning process for adaptive buildings right from the beginning. For the integration of the Life Cycle Assessment (LCA), four temporal and content-related interfaces were identified in the planning process. Inputs and outputs of the LCA were defined for the relevant planning stages in order to enable the greatest possible benefit for the planners and to minimize the environmental impacts as far as possible. The result of the research work is a methodology that can be used in the future to reduce life cycle-related environmental impacts in the planning process of adaptive buildings (ReAdapt).Item Open Access Structural systems for highrise buildings(1985) Sobek, WernerThe report was written in the United States under the first Fazlur R. Khan Fellowship in 1984 and it was completed in Germany afterwards. "Highrise Buildings" was selected by the author as the draft-title for the activities during the fellowship. Under this theme the author studied the single aspects of highrise buildings as for example planning methods, architectural considerations, structuraI systems. This was done by working at the offices of Skidmore, Owings and Herrill in Chicago and San Francisco, it was done by studying at the Illinois Institute of Technology, by visiting and discussing with different people and firms and by visiting lectures at different places. The paper presented here is a condensed result of the studies done during the fellowship with a special view at different places.Item Open Access New perspectives in architecture through transformable structures : a simulation study(2023) Matheou, Maria; Phocas, Marios C.; Christoforou, Eftychios G.; Müller, AndreasStructures enabling transformability of buildings, components and materials at different levels gain significance in view of a sustainable built environment. Such structures are capable of obtaining different shapes in response to varying functional, environmental or loading conditions. Certain limitations of classic tensegrity and scissor-like structures, applied so far in an architectural and engineering context, are attributed to a limited number of possible configurations and a big number of actuators required. In this context, rigid-bar linkages offer a promising alternative with regard to constructability, modularity, transformability and control components integration. In achieving improved flexibility and controllability with a reduced number of actuation devices, a kinematics principle has been previously proposed by the authors that involves the reduction of the system to an externally controlled one degree-of-freedom mechanism in a multistep transformation process. The paper presents application of the kinematics principle in two classes of a transformable spatial rigid-bar linkage structure. Investigation of the system kinematics was conducted using parametric associative design. The kinematics principle is applied on a torus-shaped spatial structural system composed of planar interconnected linkages. Alternative motion sequences of multiple transformation steps by the planar linkages can be implemented for the stepwise adjustment of the joints to their desired values. The actuators employed are positioned at the ground supports and are detached from the main structural body. Thus, minimum structural self-weight, simplicity and reduced energy consumption become possible. The transformation approaches using parametric associative design are exemplified based on a selected motion sequence pattern. The case study demonstrates the high degree of control flexibility and transformability of the system.Item Open Access Performance evaluation and strengthening of deficient beam-column sub-assemblages under cyclic loading(2009) Sasmal, Saptarshi; Novák, Balthasar (Prof. Dr.-Ing. )Evidence from the previous earthquakes has posed a serious question on the performance of reinforced concrete (RC) structures, both existing and newly built, under seismic loading. In the present study, exterior beam-column sub-assemblage which is proved to be one of the most critical components of an RC structure has been chosen for investigation. European Codes and Indian Standards of practice for seismic design have been considered for designing and detailing the sub-assemblages of a most regular and conventional RC structure. Different specimens represented the existing condition of buildings designed according to the available knowledge and prevailing guidelines at different times. The experimental investigations under repeated cyclic loading have shown that "GLD" specimen can hardly withstand any reverse loading due to insufficient reinforcement, inadequate bonding and poor detailing. Among the "NonDuctile" specimens, Indian Standard based specimen exhibited better performance (strength deterioration, stiffness degradation and energy dissipation) over the Eurocode based specimen, even though in both cases energy dissipation was mainly through the damage in joint region which is extremely unwanted. The strength hierarchy of all the specimens has been developed based on the results obtained from experimental and analytical studies for identification and quantification of required improvements of deficient sub-assemblages towards "Ductile" ones. After the experimental investigations, severely damaged specimens were further studied for adequate retrofitting to ensure their re-usability in post-earthquake scenario. An effective, simple and economical retrofitting scheme has been proposed here by judiciously using GFRP in members beyond the joint and steel plate in the joint region holding by through-through bolts. Surface treatment and epoxy injection were carried out to re-install concrete integrity and bond. From the experimental investigation, it has have noted that the retrofitted "NonDuctile" and "Ductile" specimens could be able to regain, if not better, their original seismic performance. Deformation capacity of the retrofitted "NonDuctile" specimen was also considerably increased with respect to undamaged ones. Further, in both retrofitted specimens, strength deterioration with increase in displacement demand was extremely low. Thus, the retrofitting schemes as proposed in this study could effectively be implemented for damaged "NonDuctile" or "Ductile" sub-assemblages for their further usage. Three different schemes have been proposed in this study for upgradation of poorly designed "GLD" structures which are present in massive quantity throughout the world. The schemes have been developed by using hybrid FRP-steel plate system. Using the analytical formulation, a detailed study has been carried out on improvement of strength and ductility due to application of external reinforcement and confinement. CFRP fabric and CFRP laminate were used for flexural strengthening, GFRP wrap was used for confinement of beam and column sections and steel plate-bolt system was adopted for confinement and shear strength enhancement of the joint. From the cyclic load test as adopted for original "GLD" specimen, it has been observed that the seismic performance of the upgraded specimens can be considerably improved by using these schemes. For example, double the energy dissipation was achieved at same drift ratio and final energy dissipation was 5 times more than that obtained from original "GLD" specimen. Most importantly, the plastic hinge shifted in the beam away the joint and in last upgraded specimen where only D-region upgradation was carried out, it could even form a spread plastic hinge in the beam, which ensures large and consistent dissipation of energy with increase in drift demand. Finally, non-linear Finite Element analysis using software ATENA has been carried out on "GLD", "NonDuctile" and upgraded specimens. Material and geometrical models have suitably been incorporated in the numerical analyses. The results obtained from numerical analyses are in good agreement with that from experimental investigations. A comparative study on energy dissipation obtained from both numerical and experimental studies has been carried out and correlated for practical use. Influence of axial load in column has also been explored. Further, a parametric study has also been conducted to investigate the effects of amount of bending FRP, number of wrapping layers, bond behaviour and role of individual upgradation components on the overall performance of the upgraded specimens which would offer the scope for any further modifications on the proposed schemes. The study as a whole would provide the promising aspects on strengthening of deficient structural components and encourage for further research.Item Open Access Global optimal actuator placement for adaptive structures : new formulation and benchmarking(2024) Senatore, Gennaro; Virgili, Francesco; Blandini, LucioCivil structures are often overdesigned to meet safety and functionality criteria under rare, strong events. Adaptive structures, however, can modify their response through sensing and actuation to satisfy design criteria more efficiently with better material utilization, which results in lower resource consumption and associated environmental impacts. Adaptation is performed through actuators integrated into the structural layout. Several methods exist for optimal actuator placement to control displacements and internal force flow. In discrete systems like trusses and frames, actuator placement is typically a binary assignment. Most existing methods use bilevel and heuristic formulations, leading to suboptimal solutions without proving global optimality. This paper introduces a Mixed Integer Programming (MIP) method that produces global optimum solutions by optimizing both actuator placement and commands. Two objective functions are used: minimizing the number of actuators and minimizing control energy. The optimization considers structural and serviceability limits and control feasibility. An extensive benchmark compares the new formulation’s global optima with solutions from greedy, stochastic, and heuristic methods. Results show that the new method consistently produces higher-quality solutions than all other methods benchmarked in this study.Item Open Access Zero-waste sand formworks for lightweight concrete structures(2025) Kovaleva, Daria; Sobek, Werner (Prof. Dr. Dr. E.h. Dr. h.c.)To address the growing urgent need to reduce resource consumption, embodied energy, and waste in construction, this thesis presents a new method for the zero-waste production of lightweight concrete structures using water-soluble sand formwork. The application of lightweight construction principles allows the creation of efficient and expressive structures with minimal material consumption and, consequently, an ecological footprint. Due to its ability to take any conceivable shape, concrete provides architects and engineers with virtually unlimited design freedom and is ideal for putting these principles into practice. However, despite the wide availability of design solutions known since the middle of the 20th century, lightweight concrete structures are still not widely used due to the lack of adequate sustainable production methods. This often involves formwork manufacturing, which is still labor-intensive and wasteful and accounts for over two-thirds of the production budget. Digital production methods, such as additive and subtractive manufacturing, enable highly precise creation of geometrically complex objects. However, their broader application in formwork production is limited by their narrow specialization in the types of geometry produced, the generation of waste during processing, and the use of toxic and non-recyclable formwork materials. Therefore, the emergence of a flexible and environmentally friendly formwork method suitable for producing geometrically complex structures is necessary for the broader application of lightweight construction with concrete. Offering a comprehensive approach to the above-described problem, this thesis proposes a novel zero-waste technology to produce lightweight concrete structures using additive manufacturing of a specially developed water-soluble sand and binder mixture. The powder-bed-based 3D printing of granular materials gives the greatest freedom in terms of geometric complexity, while the water-soluble nature of the formwork material mix allows it to be fully recycled after casting and reused in further production cycles. Following the overall goal of promoting lightweight concrete construction, this technology also has an inverse effect on designing lightweight structures. It makes it possible to realize structural morphologies that would be inefficient or even impossible to produce with conventional formwork methods. The water solubility of the formwork material allows the creation of structures with geometrically complex external shapes and internal configurations. This enables not only improved structural performance but also the integration of other functional elements, such as MEP systems, acoustic and thermal insulation. The work on the thesis includes the conceptualization of a closed-loop production cycle, the creation of an automated manufacturing process based on 3D printing of sand molds with a specially developed material mix, and the development of necessary accompanying CAD-CAM tools. The proposed technology is validated in the production of formworks for lightweight concrete structures of various scales, from small-scale prototypes to architectural demonstrator.