Jan Knippers

Zusammenfassung

The increasing use of timber in multi-story construction has highlighted challenges related to the vibration behavior of timber floor slabs, affecting both structural and acoustic performance. Floor vibrations between 0 and 20 Hz and structure-borne sound especially between 50 and 100 Hz are impairing the user comfort and serviceability. This paper investigates a mono-material approach using wooden tuned mass dampers (TMDs) to reduce these vibrations in timber slabs, particularly in buildings with long spans. Eigenmodes in relevant frequency ranges are first identified, followed by the separate design and interdisciplinary integration of TMDs for structural and acoustic performance. The study integrates acoustic and structural design requirements through an interdisciplinary process, employing both experimental and numerical models. Results demonstrate that wooden TMDs can address both disciplines and reduce deflection in timber slabs and improve structure-borne and low-frequency sound transmission.

Zusammenfassung

Robotic coreless filament winding with natural fibres and bio-based resin systems offers potential solutions to address productivity and sustainability challenges in the construction sector. Their use in modular, prefabricated structures enables efficient, controlled, and eco-jriendly production, yielding high-quality building components with minimal production waste. Plant fibres like jlax provide good strength and stiffness while requiring less non­renewable energy compared to traditional fibres like glass or carbon. This research focuses on the use and implementation of jlax fibre for coreless filament wound structural components by describing the conceptualization, design, fabrication, and assembly of a full-scale architectural demonstrator, the livMats Pavilion.

Zusammenfassung

A continuously adjustable façade shading system functionalized with photovoltaics enables, besides adaptive shading, energy harvesting by solar tracking. This requires large bending motion in two directions. In this paper, the development of an appropriate façade module – FlectoSol – is presented. To achieve motion of ±80°, first time two pneumatic actuators are integrated into a GFRP-elastomer hybrid composite. To improve energy efficiency resp. air pressure consumption of actuation without impairing shading, a parametric study is performed. In detail the influencing criteria of the bending motion “overlap of the actuators” resp. “stiffness ratio of the actuator-surrounding GFRP” and their effect on the target parameters “bending angle”, “shadow width” resp. “air pressure consumption” are analyzed. It could be stated that the “stiffness ratio” only effects the air pressure consumption, but the “overlap” also effects the shadow width. The bending angle itself is, up to ±80°, only limited by the absolute laminate stiffness.

Zusammenfassung

Modular floor slabs must be subdivided into prefabricable, transportable segments. This slab segmentation process conventionally uses a rectangular pattern, particularly for timber buildings. Regular segmentation patterns and strict column grids are ideal for rectangular building shapes, but restrict timber buildings to only some architectural uses, and are unideal for urban infill. Unfortunately, planning and constructing multi-storey wood buildings without a strict grid is still challenging. There is therefore a conflict between the desired column placement and the constraints imposed by building systems. This article investigates novel methods for segmenting timber floors supported by irregular column layouts. It proposes six different segmentation methods that are informed through Co-Design by structural, material waste, and transportation requirements. Co-Design allows for the direct integration and automated feedback of such diverse criteria into the early building design phase. These methods are based on three well-known computational approaches: Single-Objective Optimisation, Parametric Modelling, and Agent-Based Modelling. They could also be applied to other non-timber prefabricated floor systems. The segmentation methods are demonstrated on two example floor slabs with irregular column layouts, one with a rectilinear and the other with an irregular outline. The methods are compared using quantitative proxies for cost, fabrication time, architectural adaptability, and assembly complexity. More benchmark testing is needed, but initial results showed that the most efficient segmentations cannot adapt to irregular layouts, emphasising the need for a more adaptable approach to modular timber construction.

Zusammenfassung

The utilization in architecture of computational design and digital fabrication, coupled with the exploration of new material systems, brings the potential to break with conventional ways of building. However, these emerging nonstandard structures also demand new ways of designing and proving the structure’s integrity and safety. This paper aims to develop an integrative structural design methodology and workflow to design, optimize, and validate nonstandard building systems by combining a multiscale and digital-physical approach. The methods are showcased with coreless filament winding (CFW) structures, an additive manufacturing method representative of nonstandard building systems made possible by robotic fabrication. The results demonstrate the potential of this methodology to shorten the gap between research and industry, facilitating the realization of innovative structures.

Zusammenfassung

To meet climate change goals and respond to increased global urbanisation, the building industry needs to improve both its building technology and its design methods. Constrained urban environments and building stock extensions are challenges for standard timber construction. Co-design promises to better integrate disciplines and processes, promising smaller feedback loops for design iteration and building verification. This article describes the integrated design, fabrication, and construction processes of a timber building prototype as a case study for the application of co-design methods. Emphasis is placed on the development of design and engineering methods, fabrication and construction processes, and materials and building systems. The development of the building prototype builds on previous research in robotic fabrication (including prefabrication, task distribution, and augmented reality integration), agent-based modelling (ABM) for the design and optimisation of structural components, and the systematisation of timber buildings and their components. The results presented in this article include a functional example of co-design from which best practises may be extrapolated as part of an inductive approach to design research. The prototype, with its co-designed process and resultant flat ceilings, integrated services, wide spans, and design adaptability for irregular column locations, has the potential to expand the design potential of multi-storey timber buildings.

Zusammenfassung

Coreless filament winding extends established industrial processes, enabling the fabrication of building parts with minimal formwork. Since the part's final geometry is unknown until completed, it creates uncertainties for design and engineering. Existing architectural design workflows are insufficient, and industrial software packages cannot capture the complexity of self-deforming fibres to model complex fibre layups. This research introduces a feedback-based computational method conceived as four development cycles to design and evaluate fibre layups of large-scale architectural building components, and a multi-scalar digital-physical design and evaluation toolset to model and evaluate them at multiple resolutions. The universal applicability of the developed methods is showcased by two different architectural fibre structures. The results show how the systematization of methods and toolset allow for increased design flexibility and deeper integration of interdisciplinary collaborators. They constitute an important step towards a consolidated co-design methodology and demonstrate the potential to simultaneously co-evolve design and evaluation methods.

Zusammenfassung

Currently, there is a tendency to use Islamic Geometric Patterns (IGPs) as important identities and cultural elements of building design in the Middle East. Despite high demand, lack of information about the potential of IGPs principles have led to formal inspiration in the design of existing buildings. Many research studies have been carried out on the principles of IGPs. However, comprehensive studies relating to new possibilities, such as structure-based, sustainablebased, and aesthetic-based purposes, developed by computer science and related technologies, are relatively rare. This article reviews the state-of-the-art knowledge of IGPs, provides a survey of the main principles, presents the status quo, and identifies gaps in recent research directions. Finally, future prospects are discussed by focussing on different aspects of the principles in accordance with collected evidence obtained during the review process.

Zusammenfassung

The linear design workflow for structural systems, involving a multitude of iterative loops and specialists, obstructs disruptive innovations. During design iterations, vast amounts of data in different reference systems, origins, and significance are generated. This data is often not directly comparable or is not collected at all, which implies a great unused potential for advancements in the process. In this paper, a novel workflow to process and analyze the data sets in a unified reference frame is proposed. From this, differently sophisticated iteration loops can be derived. The developed methods are presented within a case study using coreless filament winding as an exemplary fabrication process within an architectural context. This additive manufacturing process, using fiber-reinforced plastics, exhibits great potential for efficient structures when its intrinsic parameter variations can be minimized. The presented method aims to make data sets comparable by identifying the steps each data set needs to undergo (acquisition, pre-processing, mapping, post-processing, analysis, and evaluation). These processes are imperative to provide the means to find domain interrelations, which in the future can provide quantitative results that will help to inform the design process, making it more reliable, and allowing for the reduction of safety factors. The results of the case study demonstrate the data set processes, proving the necessity of these methods for the comprehensive inter-domain data comparison.

Zusammenfassung

This research investigated building components that can be produced and transported in a flat state and transformed to a spatial state without scaffolding on-site. Curved folding was employed to allow for a shape change between flat and spatial bending active structures. Bending generally allows for expressive curvature with simple flat production as well as easy customization. Limitations presented by laborious forming and upscaling of individually bent plates were overcome by large-scale curved folding. The present research builds upon the context but adds a design framework for volumetric curved folded components, a bistable behavior, and comprehensive detailing regarding upscaling and increased structural capacity. The mechanism was studied on a kinematic level, considering geometrical rules of curved folding and the design space. It was also studied on a kinetic level under the consideration of material properties specific to plywood. As a proof of concept, a 1:1 scale demonstrator was built. Finite element modeling software was used to optimize the shape. The demonstrator was fabricated flat, folded up, and locked in its stable configuration by the bistability and bases. It supported twelve people with a self-weight of approximately 300kg.

Zusammenfassung

Structural members made of fiber-reinforced polymers (FRP) attract increasing attention in the development of novel architectural systems that challenge the standard design methodologies. Cylindrical surfaces constitute one of the typical geometric sets obtained with the FRP component fabrication. This paper explores the influences of two geometric parameters on the buckling performance of elliptical cylinders: inverse slenderness (ratio of minimum diameter to height) and eccentricity (ratio of radii along semi-axes). The overall stiffness properties are defined using lamination parameters. This analysis method eliminates the dependency of optimal solutions on the initial assumptions regarding the laminate configuration, which needs to be explicitly described in multi-layer modeling. Finite element analyses are utilized to compute buckling loads of the cylinders under axial compression force and bi-axial bending moments. The optimal lamination parameters and buckling stresses are determined for various parameters, and the lamination parameters corresponding to the optimal and simple ±45° angle-ply design points are presented in the lamination parameter plane via Miki's diagram. The results reveal the level of performance that can be achieved by a specific geometry and provide guidelines for the optimal design of elliptical laminated cylinders against buckling.

Zusammenfassung

Coreless filament winding is an emerging fabrication technology in the field of building construction with the potential to significantly decrease construction material consumption, while being fully automatable. Therefore, this technology could offer a solution to the increasing worldwide demand for building floor space in the next decades by optimizing and reducing the material usage. Current research focuses mainly on the design and engineering aspects while using carbon and glass fibers with epoxy resin; however, in order to move towards more sustainable structures, other fiber and resin material systems should also be assessed. This study integrates a selection of potential alternative fibers into the coreless filament winding process by adapting the fabrication equipment and process. A bio-based epoxy resin was introduced and compared to a conventional petroleum-based one. Generic coreless wound components were created for evaluating the fabrication suitability of selected alternative fibers. Four-point bending tests were performed for assessing the structural performance in relation to the sustainability of twelve alternative fibers and two resins. In this study, embodied energy and global warming potential from the literature were used as life-cycle assessment indexes to compare the material systems. Among the investigated fibers, flax showed the highest potential while bio-based resins are advisable at low fiber volume ratios.

Zusammenfassung

Coreless filament winding (CFW) is a novel fabrication technique that utilises fibre-polymer composite materials to efficiently produce filament wound structures in architecture while reducing manufacturing waste. Previous projects have been successfully built with glass and carbon fibre, proving their potential for lightweight construction systems. However, in order to move towards more sustainable architecture, it is crucial to consider replacing carbon fibre’s high environmental impact with other material systems, such as natural fibre. This paper evaluates several fibres, resin systems, and their required CFW fabrication adjustments towards designing and fabricating a bio-composite structure: the LivMatS Pavilion. The methods integrate structural design loops with material evaluation and characterisation, including small-scale and large-scale structural testing at progressive stages. The results demonstrate the interactive decision-making process that combines material characterisation with structural simulation feedback, leveraged to evaluate and optimise the structural design. The built pavilion is proof of the first successful coreless filament wound sustainable natural fibres design, and the developed methods and findings open up further research directions for future applications.

Zusammenfassung

Coreless filament winding is a robotic fabrication technique in which conventional filament winding is modified to reduce the core material to its minimum. This method was showcased and developed through a series of pavilions demonstrating its potential to create lightweight structures. The latest project, Maison Fibre, goes one step further and adapts the fabrication into a hybrid structure combining fibre-polymer composites (FPC) with laminated veneer lumber (LVL) to allow for walkability. The result is the first multi-storey building system fabricated with this novel technique. During the integrative design process of the slab system, the optimum fibre layup was negotiated between the timber support span, load induction, boundary conditions, and material amount required. A total of four iterations of the hybrid component were load tested and compared with the maximum enveloped forces resulting from the global structural simulation. The full-scale load tests were used to calibrate the refined structural simulation of the slab components. The experimental process allowed for material reduction and validated the structural system's capability to withstand the design forces. In addition, the fibre layup was tailored and load adapted for the non-tested wall and slab components of the installation using the test results and achieving further material optimization. This publication describes the integrative design process of the hybrid slab system from initial concepts to the iterative optimization of the structural system, demonstrating its potential for future applications.

Zusammenfassung

Recent efforts on the research of bending- and tensile-active structures have shown the vast range of aesthetic and performative opportunities that elastic structures can offer for generating innovative architectural solutions. In this context, the task of conceptualizing and representing elastic structures is not trivial due to the presence of large deformations along the forming process. This condition demands to expand beyond current geometrical modeling schemes used in architecture and develop a more intuitive simulation-based design practice. Dynamic methods, such as Particle System and Dynamic Relaxation, have become an important topic on this subject with major efforts entirely focused on speeding up rates of numerical convergence. Fast simulations simplify the development of design iterations, but designers are still forced to break the integration process when topological changes need to be introduced for fulfilling a given design intention. As the exploration of elastic structures becomes more integrated within architectural design agendas, there is a growing necessity to introduce more flexible numerical models for design conceptualization. In this paper we introduce the conceptual framework for a generic Particle System model built on principles of combinatorial maps and graph theory that is designed to support topological transformations on the fly. The computational implementation of the proposed model is demonstrated with two types of data structures. The aim of this work is to enhance modeling capabilities when numerical simulations are used as design tools.

Zusammenfassung

In coreless filament winding, resin-impregnated fibre filaments are wound around anchor points without an additional mould. The final geometry of the produced part results from the interaction of fibres in space and is initially undetermined. Therefore, the success of large-scale coreless wound fibre composite structures for architectural applications relies on the reciprocal collaboration of simulation, fabrication, quality evaluation, and data integration domains. The correlation of data from those domains enables the optimization of the design towards ideal performance and material efficiency. This paper elaborates on a computational co-design framework to enable new modes of collaboration for coreless wound fibre–polymer composite structures. It introduces the use of a shared object model acting as a central data repository that facilitates interdisciplinary data exchange and the investigation of correlations between domains. The application of the developed computational co-design framework is demonstrated in a case study in which the data are successfully mapped, linked, and analysed across the different fields of expertise. The results showcase the framework’s potential to gain a deeper understanding of large-scale coreless wound filament structures and their fabrication and geometrical implications for design optimization.

Zusammenfassung

The applications of fiber-reinforced polymer (FRP) composites extend rapidly along with the development of new manufacturing techniques. However, due to the complexities introduced by the material and fabrication processes, the application of conventional structural design methods for construction members has been significantly challenging. This paper presents an alternative methodology to find optimum fiber layups for a given tube-shape geometry via a graphical optimization strategy based on structural performance requirements. The proposed technique employs simplified shell element models based on classical lamination theory (CLT) to avoid explicit fiber modeling in the FEA simulations. Lamination parameters are utilized to generate the reduced stiffness matrices for continuous multi-layer FRP lamination. The fiber layup of the component is retrieved from the optimal lamination parameters that maximize the structural performance. The case study results demonstrate that the developed method provides compact solutions, linking the structural design requirements with optimal fiber orientations and volumetric proportions. In addition, the determined solutions can be interpreted directly by the winding fabrication settings.

Zusammenfassung

Though capable of allowing multi-directional spans, timber products such as cross-laminated timber are primarily utilized uni-directionally using linear supports like walls or beam elements. Recent building designs increasingly show punctual supports but with narrow column grid layouts. Support beams and narrow grids limit the design space for multi-storey timber buildings. To overcome these design limits, an integrative design concept for punctually supported timber slabs is being developed that allows for large spans and irregular column layouts. Therefore, engineering methods are integrated in the architectural design of the building components, such as plates, columns, and their connections. The developed slab system combines hardwood and softwood materials in a sandwich construction. The plates have a tailored internal topology considering the force flow in the slab. A plate-to-plate connection design is evaluated through mechanical tests, which also serve as calibration for the global structural model. The research findings are validated through the design and construction of a large scale demonstrator: the ITECH Campus Lab.

Zusammenfassung

Fiber-reinforced composite structures manufactured by coreless filament winding (CFW) are adaptable to the individual load case and offer high, mass-specific mechanical performance. However, relatively high safety factors must be applied due to the large deviations in the structural parameters. An improved understanding of the structural behavior is needed to reduce those factors, which can be obtained by utilizing an integrated fiber-optical sensor. The described methods take advantage of the high spatial resolution of a sensor system operating by the Rayleigh backscatter principle. The entire strain fields of several generic CFW samples were measured in various load scenarios, visualized in their spatial contexts, and analyzed by FEM-assisted methods. The structural response was statistically described and compared with the ideal load distribution to iteratively derive the actual load introduction and prove the importance of the sensor integration. The paper describes methods for the sensor implementation, interpretation and the calibration of structural data.

Zusammenfassung

The arrangement of columns and their spacing in multi-story timber construction is restricted to rectangular grids by the production and shipping sizes of floor assemblies. This is particularly true for hollow box floor systems, for which the punctual supports must be placed at the reinforced edges of the hollow boxes. The arrangement of the columns and their spacing is thereby restricted by the production and shipping sizes of the box ceilings to rectangular grids. To overcome these design limits a new wooden box building system is developed that allows for irregular column layouts through a tailored slab interior design. This development allows for the increased applicability of timber floor systems regardless of site shape or architectural design intent. The slab interior design is dependent on occurring forces and fabrication requirements. Three methods for the internal slab layout are developed and compared: a sequential method, a structurally informed agent-based method, and a geometrically informed agent-based method that uses both a sequential and agent-based approach. The structural performance of each method is compared through the analysis of three reinforcement layouts an architectural testing setup.

Zusammenfassung

In building industries, branched load-bearing structures are used for defined load transfer and load distribution. While fiber-reinforced plastics are established as concrete formwork for straight segments, node geometries are less available. This is caused by the complex manufacturing process of spatially branched, three-dimensional textile preforms. There are only few productive textile processes for the manufacture that are attractive to industry, the most common is braiding. However, setting up the process, including programming the mandrel path through the braiding machine and adjusting the fiber placement, is very time consuming, making the process unattractive despite high productivity. This paper presents a new digitalized process workflow for the fabrication which simplifies the process preparation and thus could establish the braiding process for rapid fabrication of spatially branched, three-dimensional geometries. The digitalized workflow is validated by manufacturing a 4-arm node structure consisting of a concrete-filled CFRP in a scale relevant to the building industry.

Zusammenfassung

Recent development in research and practice for curved cross-laminated timber (CLT) opens up novel and interesting possibilities for applications of slender surface-active shell structures in architecture. Such typologies provide advantageous structural behaviour allowing for efficient and lightweight structures while simultaneously determine the envelope and space of a building. The high degree of prefabrication combined with a sustainable and renewable building material makes CLT an ecological and economic solution for future construction. This paper presents the design development and construction of the Urbach Tower for the Remstal Gartenschau 2019: a structure made from high curvature CLT components on a building scale. This research contribution illustrates a sophisticated integrative design to construction process emphasizing computational and structural design, fabrication and detailing for curved timber components in complex spatial structures. The authors further explore the structural potential of self-shaped curved CLT investigating the influence of curvature radius on the load-bearing behaviour of the tower structure. The Urbach Tower translates these technical developments into practice arising at the intersection of digital innovation and scientific research.

Zusammenfassung

A hemispherical research demonstration pavilion was presented to the public from April to October 2019. It was the first large-scale lightweight dome with a supporting roof structure primarily made of carbon- and glass-fiber-reinforced composites, fabricated by robotic coreless filament winding. We conducted monitoring to ascertain the sturdiness of the fiber composite material of the supporting structure over the course of 130 days. This paper presents the methods and results of on-site monitoring as well as laboratory inspections. The thermal behavior of the pavilion was characterized, the color change of the matrix was quantified, and the inner composition of the coreless wound structures was investigated. This validated the structural design and revealed that the surface temperatures of the carbon fibers do not exceed the guideline values of flat, black façades and that UV absorbers need to be improved for such applications.

Zusammenfassung

The BUGA Fibre Pavilion was built in 2019 in the Bundesgartenschau (National Gardening exhibition) at Heilbronn, Germany. The pavilion consists of modular fibre-polymer composite components made out of glass and carbon fibres with an epoxy resin matrix. The fabrication technique employed, called coreless filament winding (CFW), is a variant from conventional filament winding where the core is reduced to minimum frame support. The fibres are wound between these frames, freely spanning and creating the resulting geometry through fibre interaction. For the structural design of these components, conventional modelling and engineering methods were not sufficient as the system cannot be adequately characterized in the early stage. Therefore, a more experimental design approach is proposed for the BUGA Fibre Pavilion, where different levels of detailing and abstraction in the FE simulations are combined with prototyping and structural testing. This paper shows the procedure followed for the design and validation of the structural fibre components. In this process, the simulations are used as a design tool rather than a way to predict failure, while mechanical testing served for the verification and validation of the structural capacity.

Zusammenfassung

Increasing the construction capacity, while at the same time significantly reducing harmful emissions and consumption of nonrenewable resources, and still providing a liveable and affordable built environment, provides a great challenge for future construction. In order to achieve this, both the productivity of construction processes and the energy and resource efficiency of construction systems have to be improved in a reciprocal process. Digital technologies make it possible to address these challenges in novel ways. The vision of this Cluster of Excellence IntCDC at the University of Stuttgart and the Max Planck Institute for Intelligent Systems is to harness the full potential of digital technologies to rethink design and construction based on integration and interdisciplinarity, with the goal of laying the methodological foundations to profoundly modernize the design and construction process and related building systems by adopting a systematic, holistic and integrative computational approach. One key objective is to develop an overarching methodology of “co-designing” methods, processes and systems based on interdisciplinary research encompassing architecture, structural engineering, building physics, engineering geodesy, manufacturing and systems engineering, computer science and robotics, and humanities and social sciences. In this way, the Cluster aims to address the ecological, economic and social challenges and to provide the prerequisites for a high-quality and sustainable built environment and a digital building culture.

Zusammenfassung

This paper aims to define the influencing design criteria for compliant folding mechanisms with pneumatically actuated hinges consisting of fiber-reinforced plastic (FRP). Through simulation and physical testing, the influence of stiffness, hinge width as well as variation of the stiffness, in the flaps without changing the stiffness in the hinge zone, was evaluated. Within a finite element model software, a workflow was developed for simulations, in order to infer mathematical models for the prediction of mechanical properties and the deformation behavior as a function of the aforementioned parameters. In conclusion, the bending angle increases with decreasing material stiffness and with increasing hinge width, while it is not affected by the flap stiffness itself. The defined workflow builds a basis for the development of a predictive model for the deformation behavior of FRPs.

Zusammenfassung

Die Herausforderung an das Bauen der Zukunft besteht darin, mehr zu bauen, dabei weniger Schadstoffe zu emittieren und weniger endliche Ressourcen zu verbrauchen und trotzdem eine qualitätsvolle und lebenswerte gebaute Umwelt zu schaffen. In einem sich wechselseitig beeinflussenden Prozess müssen hierfür sowohl die Produktivität der Bauprozesse als auch die Energie‐ und Ressourceneffizienz der Bausysteme verbessert werden. Digitale Technologien bieten neue Lösungsansätze für diese Herausforderungen. Ziel des Exzellenzclusters IntCDC an der Universität Stuttgart und dem Max‐Planck‐Institut für Intelligente Systeme ist es, das volle Potential digitaler Technologien zu nutzen, um das Planen und Bauen in einem integrativen und interdisziplinären Ansatz neu zu denken und damit die methodischen Grundlagen für eine umfassende Modernisierung des Bauschaffens zu legen. Eine zentrale Zielsetzung ist die Entwicklung einer übergeordneten Methodologie des „Co‐Design“ von Methoden, Prozessen und Systemen, basierend auf interdisziplinärer Forschung zwischen den Bereichen Architektur, Bauingenieurwesen, Ingenieurgeodäsie, Produktions‐ und Systemtechnik, Informatik und Robotik sowie Geistes‐ und Sozialwissenschaften. So sollen Lösungswege für die ökologischen, ökonomischen und sozialen Herausforderungen aufgezeigt und die Voraussetzungen für eine qualitätsvolle, lebenswerte und nachhaltige gebaute Umwelt sowie für eine digitale Baukultur geschaffen werden.

Zusammenfassung

The multi-stage filament winding (MSFW) method enables the sustainable production of lightweight fibre composites with complex geometries. Double curved components, even with undercuts, are analysed and concave areas which are not suitable for filament winding are replaced by convex temporary geometries. Permanent and temporary mandrel parts are combined for the stage-based fabrication method. The sand composites developed for MSFW mandrels can be washed out using water. The sand can be reused. This paper introduces the fabrication method, presents the status of the research, and focuses on the geometry generation algorithm of the integrative design process.

Zusammenfassung

The presented research describes the holistic development of a modular lightweight timber shell. So-called segmented timber shells approximate curved geometries with the use of planar plates, thus combining the excellent structural performance of double curved shells with the resource-efficient prefabrication of timber modules using only planar elements. Segmented timber shells constitute a novel building system that demands for innovative approaches on structural design and construction technologies. The geometric complexity of plate shells in conjunction with the particularities of the building material wood pose great challenges to the computational design and planning processes as structural requirements and fabrication constraints determine the shell design at early design phases. This paper discusses the design development and construction of the BUGA Wood Pavilion: A segmented timber shell structure made of hollow cassette components. Particular emphasis lies on the technical challenges of the employed building system, notably structural design and analysis, detailing solutions and the construction process. The authors further describe the integrative structural design and optimization methods developed for the timber shell in question. The BUGA Wood Pavilion demonstrates the possibilities of lightweight and sustainable wood architecture merging the merits of integrative design, structural engineering and high-tech robotic fabrication methods.

Zusammenfassung

Adaptive shading devices are of special interest in the context of global need for reducing greenhouse gas emissions. To reduce mechanical complexity of kinetic architectural applications, the investigation of bio-inspired compliant mechanisms has proven to be a promising approach. Thus, a coherent integrative design framework for bio-inspired kinetic folding mechanisms has been developed. This includes the abstraction process of biological principles, such as kinematic behaviours, actuation, as well as materialisation principles. A computational design and simulation model is built to analyse the kinematic and kinetic behaviour of the abstracted biological principles under consideration of specific materialisation and fabrication parameters and constraints. The design and simulation model builds the basis for an automated fabrication process, as well as for interaction and active control of the physical application. The development of the ITECH Research Demonstrator 2018-19, a large-scale compliant folding mechanism, inspired by the folding behaviour ladybug wings (Coleptera coccinellidae), serves as a case study of the developed process. The folding motion of the demonstrator is facilitated by distinct elastic hinge-zones with integrated pneumatic actuators.

Zusammenfassung

Within the framework of a biomimetic top-down approach, our study started with the technical question of the development of a hinge-free and compliant actuator inspired by plant movements. One meaningful biological concept generator was the opening and closing movements of the leaf halves of grasses. Functional morphological investigations were carried out on the selected model plant Sesleria nitida. The results formed the basis for further clarifying the functional movement principle with a particular focus on the role of turgor changes in bulliform cells on kinetic amplification. All findings gained from the investigations of the biological model were incorporated into a finite-element analysis, as a prerequisite for the development of a pneumatic cellular actuator. The first prototype consisted of a row of single cells positioned on a plate. The cells were designed in such a way that the entire structure bent when the pneumatic pressure applied to each individual cell was increased. The pneumatic cellular actuator thus has the potential for applications on an architectural scale. It has subsequently been integrated into the midrib of the facade shading system Flectofold in which the bending of its midrib controls the hoisting of its wings.

Zusammenfassung

The BUGA fibre pavilion built in April 2019 at the Bundesgartenschau in Heilbronn, Germany, is the most recent coreless fibre winding research pavilion developed from the collaboration between ICD/ITKE at the University of Stuttgart. The research goal is to create lightweight and high-performance lattice composite structures through robotic fabrication. The pavilion is composed of 60 carbon and glass fibre components, and is covered by a prestressed ethylene tetrafluoroethylene (ETFE) membrane. Each of the components is hollow in section and bone-like in shape. They are joined through steel connectors at the intersecting nodes where the membrane is also supported through steel poles. The components are fabricated by coreless filament winding (CFW), a technique where fibre filaments impregnated with resin are wound freely between two rotating scaffolds by a robotic arm. This novel structural system constitutes a challenge for the designer when proving and documenting the load-carrying capacity of the design. This paper outlines and elaborates on the core methods and workflows followed for the structural design, optimization and detailing of the BUGA fibre pavilion.

Zusammenfassung

Regarding modern, daylight-flooded buildings with large window façades, appropriate shading systems to improve the energy consumption of climate controlling systems are becoming more relevant. Building envelopes contribute largely to the temperature control and should be at best installed on the outside to prevent the interior from heating up. Preferably, those systems work with minimum maintenance and maximum robustness, covering as much of the window area as possible. Previous shading systems were mostly based on rigid-body mechanisms using error-prone joints. Components, whose movability is achieved by a local compliance of the material, offer a way to avoid the usage of mechanical joints. Within this paper, a new fiber-reinforced plastic (FRP) façade shading demonstrator called “Flexafold” is presented. Its opening and closing movement are controlled by pneumatic cushions which are integrated directly into the laminate set-up. The Flexafold shows thereby the possibility of producing self‑supporting, adaptive FRP components whose actuators are integrated into the component and thus protected in exterior applications. The functional principles and components of Flexafold, e.g. the locally compliant FRP material, the folding pattern and the integrated actuator system, are explained within this paper. Furthermore, a comparison to existing adaptive façade shading systems “flectofin®” and “Flectofold” is given.

Zusammenfassung

Compliant mechanisms of fiber-reinforced plastic (FRP) have been developed to reduce the mechanical complexity of kinetic systems. In a further step, pneumatic actuation was integrated into the set-up of the FRP, offering lightweight, slender, and inconspicuous actuation. Inflation of an integrated cushion causes rotation through the asymmetric material lay-up. Inspiration from the ultrastructure of pressurized veins in arthropod wings has led to the development of a thin layer of elastomer surrounding this pneumatic cushion to avoid delamination. T-peel tests revealed that the elastomer forms a higher adhesion to itself than to glass-fiber-reinforced plastic (GFRP) layers with an epoxy matrix. The angle-pressure relationship for specific GFRP samples with a defined compliant hinge zone was investigated physically and numerically, showing good consistency between the two. Further, a mathematical model, taking into account the bending stiffness of the cushion-surrounding FRP layers, was developed, and a parametric study was conducted on the actuation angles.

Zusammenfassung

The ICD/ITKE Research Pavilion 2016/2017 is the most recent in the series of experimental building demonstrators developed by the Institute for Computational Design (ICD) and the Institute for Building Structures and Structural Design (ITKE) at the University of Stuttgart. The completed structure is a 12 m long cantilevering lattice-composite shell that was wound in one piece by a multi-machine fabrication system using coreless filament winding. To realise such a structure through this fabrication process involved a negotiation between architectural design, structural requirements and fabrication constraints. The structural design process was divided into two steps. A shell model was used to evaluate possible geometries in the initial negotiation between architectural design and fabrication constraints. In order to approximate the highly anisotropic material behaviour of fibre reinforced polymers, substitute material properties had to be determined in physical tests. In the second step the actual fibre layup was analysed using a detailed beam-element model. The main load bearing fibre bundles were directly analysed in cross section and position. As-built and intended geometry were constantly compared and the feedback was used to refine the finite element analysis during fabrication. This paper covers the aspects mentioned and gives an outlook on further possibilities of this design and fabrication approach.

Zusammenfassung

Hingeless shading systems inspired by nature are increasingly the focus of architectural research. In contrast to traditional systems, these compliant mechanisms can reduce the amount of maintenanceintensive parts and can easily be adapted to irregular, doubly curved, facade geometries. Previousmechanisms rely merely on the reversible material deformation of composite structures with almost homogeneous material properties. This leads to large actuation forces and an inherent conflict between the requirements of movement and the capacity to carry external loads. To enhance the performance of such systems, current research is directed at natural mechanisms with concentrated compliance and distinct hinge zones with high load-bearing capacity. Here, we provide insights into our biological findings and the development of a deployable structure inspired by the Flexagon model of hindwings of insects in general and the hierarchical structure of the wing cuticle of the shield bug (Graphosoma lineatum). By using technical fibre-reinforced plastics in combination with an elastomer foil, natural principles have been partially transferred into a multi-layered structure with locally adapted stiffness. Initial small prototypes have been produced in a vacuum-assisted hot press and sustain this functionality. Initial theoretical studies on test surfaces outline the advantages of these bio-inspired structures as deployable external shading systems for doubly curved facades.

Zusammenfassung

Textile Hybrid Structures are a novel type of structural system referring to the coupling of tensile form- and bending-active components into a stiffer construct. For form finding its static equilibrium shape, several computational frameworks built upon the Dynamic Relaxation method have been developed for the interactive exploration of material and geometric properties. However, efforts are still required when addressing dynamic alterations of topology without completely resetting the simulation. The main problem to face is the dynamic alteration of topological data without losing consistency of connectivity. In this paper, we present the development of a computational framework for form-finding textile hybrid structures which enables dynamic explorations of complex topological configurations during solver’s execution. A so-called evolving network formulation used to model mutable assemblies of interconnected particles is presented as well as the numerical scheme adopted to find the equilibrium state of such structures. The implementation of the framework is further described through the development of ElasticSpace, an interactive form finding tool for textile hybrid structures built with Java.

Zusammenfassung

In the research field of segmented timber shells, two construction systems have lately received much attention, which both expose interesting structural and constructional characteristics: planar plate structures made of thin plywood and actively bent plywood structures. The research presented in this article combines elements of both approaches, resulting in a construction system for segmented shell structures with elastically bent elements. The increasing complexity of this approach requires a sophisticated design process, which integrates fabrication constraints as well as structural feedback. As a consequence, form-finding strategies of bending-active timber shells are discussed, with a special focus on the programming of the stiffness distribution in order to fulfil geometrical requirements. The authors also reflect on the specific structural challenges of joining thin sheets of plywood by transferring traditional textile connection methods to timber construction. Investigations of biological role models such as the sand dollar led to transfers of constructional principles on different levels. The resulting construction system was validated through the design and construction of a full-scale architectural prototype

Zusammenfassung

Die Tragfähigkeit von Betondruckgliedern, wie Stützen im Hochbau, kann durch eine Umschnürung gesteigert werden. Dies erlaubt reduzierte Querschnittsabmessungen, geringeres Gewicht der Bauteile sowie einen Geschoßflächengewinn bei gleichem Traglastniveau. Es werden Untersuchungen zum Tragverhalten an unbewehrten, umschnürten Betonzylindern mit Querschnittdimensionen, die an gängige Hochbaustützen heranreichen, vorgestellt. Gewickelte und erstmals geflochtene Rohre aus kohlefaserverstärktem Kunststoff dienen als Umschnürungen. Durch den Einsatz der Hülle als verlorene Schalung kann auch der Bauablauf im Vergleich zu konventionell geschalten Stützen verbessert werden. Das gewählte Steifigkeitsverhältnis des Kerns zur Hülle führt zu einem mehraxialen Spannungszustand, durch den die Druckfestigkeit von Beton gegenüber der einachsigen Beanspruchbarkeit erheblich gesteigert werden kann. Für die Auslegung werden deshalb aktuelle Bemessungsmodelle für gewickelte Umschnürungen angewendet und ausgewertet. Anhand von Druckversuchen an je drei gewickelten und geflochtenen, mit CFK umschnürten Betonzylindern sowie an Betonreferenzprüfkörpern werden Last‐Verformungskurven in Axial‐ und Umfangsrichtung ermittelt. Die mechanischen Eigenschaften der CFK‐Umschnürung werden anhand eines Split‐Disk‐Tests geprüft. Ergebnisse aus analytischen Modellen werden den experimentellen gegenübergestellt und diskutiert.

Zusammenfassung

Smart and adaptive outer façade shading systems are of high interest in modern architecture. For long lasting and reliable systems, the abandonment of hinges which often fail due to mechanical wear during repetitive use is of particular importance. Drawing inspiration from the hinge-less motion of the underwater snap-trap of the carnivorous waterwheel plant (Aldrovanda vesiculosa), the compliant façade shading device Flectofold was developed. Based on computational simulations of the biological role-model's elastic and reversible motion, the actuation principle of the plant can be identified. The enclosed geometric motion principle is abstracted into a simplified curved-line folding geometry with distinct flexible hinge-zones. The kinematic behaviour is translated into a quantitative kinetic model, using finite element simulation which allows the detailed analyses of the influence of geometric parameters such as curved-fold line radius and various pneumatically driven actuation principles on the motion behaviour, stress concentrations within the hinge-zones, and actuation forces. The information regarding geometric relations and material gradients gained from those computational models are then used to develop novel material combinations for glass fibre reinforced plastics which enabled the fabrication of physical prototypes of the compliant façade shading device Flectofold.

Zusammenfassung

Computational design and fabrication are at the focus of advanced practice and research in architecture. They allow for local differentiation of building components that enable buildings that were unthinkable a few years earlier. However, to fully exploit the potential of computational fabrication, a new paradigm in engineering is necessary. Today, the quantitative prediction of integrity by calculation of stresses and deformations is conceived as an indispensable prerequisite for any building construction. However, each simulation is only valid within certain boundary conditions, often not able to cope with advanced material systems. This paper discusses the need for alternative engineering strategies including integrated monitoring and physical testing in the design process to overcome the limitations of simulation.

Zusammenfassung

Stay-in-place formwork is often used to accelerate the construction of structural elements such as flooring, concrete bridge decks and compressed shells. This study aims at designing, manufacturing and testing of two different nonlinear shear connectors made of fiber reinforced polymer composites for the formwork: (1) non-directional, cylindrical shear-cones; and (2) directional, cubical shear-cones with one side beveled. Six 1m-long specimens were constructed using carbon fiber reinforced polymer stay-in-place formwork and a plain concrete slab (200 wide and 130mm thick). Based on the results of three-point bending tests, similar stiffness, load–displacement response and failure mode were observed in the two contrasting designs. The resistance of the specimens using cylindrical shear-cones was approximately 26% higher than that of the ones with cubical design.

Zusammenfassung

Over the course of 3.8 billion years of biological evolution, nature has found the answers to many engineering problems. The aim of biomimetics is to analyse and tap biology's potential as a huge reservoir for innovative solutions. Thomas Speck, Professor and Director of the Plant Biomechanics Group (PBG) at the University of Freiburg and the Freiburg Centre for Interactive Materials and Bioinspired Technologies (FIT), Jan Knippers , Professor and Head of the Institute of Building Structures and Structural Design (ITKE) at the University of Stuttgart, and Olga Speck, a researcher at the PBG, scientific coordinator of FIT and manager of the Competence Network Biomimetics at Freiburg, explain how biological material systems with self‐x properties are cost‐efficient, multifunctional, and can be environmentally friendly; and with several billion trial runs, have surely stood the test of time.

Zusammenfassung

Process‐based biomimetics focuses on the transfer of biological principles to architectural construction. To realise the ICD/ITKE Research Pavilion 2014 ‐15, presented here by Moritz Doerstelmann, Jan Knippers, Valentin Koslowski, Achim Menges, Marshall Prado, Gundula Schieber and Lauren Vasey of the Institute for Computational Design (ICD) and Institute of Building Structures and Structural Design (ITKE) research team at the University of Stuttgart, sensor‐driven robotic fabrication was combined with advanced design computation and simulation. This enabled the construction of an architectural fibre structure on a pneumatic mould, drawing on the complex design of the web of a water spider.

Zusammenfassung

Biegeaktive Tragwerke sind gekrümmte Tragwerke, deren Geometrie und Systemsteifigkeit sich aus einer elastischen Verformung von Tragelementen ergibt. Biegung kann demnach dazu genutzt werden, komplexe räumlich gekrümmte Tragsysteme aus ursprünglich geradlinigen oder ebenen Tragelementen zu erzeugen. Bei der Arbeit mit biegeaktiven Tragstrukturen zeigt sich, dass dieser Formgebungsansatz die Entwicklung hocheffizienter Tragsysteme ermöglicht, welche - frei von tradierten typologischen Ansätzen der Tragwerkslehre - aus dem Kurzschließen von Rückstellkräften entstehen. Nach einer Definition der Begriffe und kurzen Darstellung der relevanten mechanischen sowie werkstofftechnischen Grundlagen werden in diesem Aufsatz die besonderen Eigenschaften dieser Tragwerke anhand von Fallbeispielen erläutert.

Zusammenfassung

Segmental plate shells are an interesting option for the design and construction of cost-effective shell structures. They are composed of prefabricated segmental plates that are joined together to become an integral structure that generates a shell action and transfers external loads into membrane forces. However, connections between segmental plates nearly always weaken shell structures as they disturb the material continuity and thus their stiffness. The application of finger joint connections can effectively increase the in-plane stiffness and thus makes plate shell structures stiffer and stronger. Moreover, they attract more forces to flow through the connection in the form of in-plane shears instead of axial forces and thus reduce the load in the axial direction of a connection. As a result, the application of finger joints allows a lighter axial joint design with smaller screw diameters, which is preferred in a thin timber plate structure. The paper presents the Landesgartenschau Exhibition Hall as a successful demonstrator for segmental timber plate shells and highlights the design of the finger joint connections.

Zusammenfassung

In architecture, kinetic structures enable buildings to react specifically to internal and external stimuli through spatial adjustments. These mechanical devices come in all shapes and sizes and are traditionally conceptualized as uniform and compatible modules. Typically, these systems gain their adjustability by connecting rigid elements with highly strained hinges. Though this construction principle may be generally beneficial, for architectural applications that increasingly demand custom-made solutions, it has some major drawbacks. Adaptation to irregular geometries, for example, can only be achieved with additional mechanical complexity, which makes these devices often very expensive, prone to failure, and maintenance-intensive.Searching for a promising alternative to the still persisting paradigm of rigid-body mechanics, the authors found inspiration in flexible and elastic plant movements. In this paper, they will showcase how today's computational modeling and simulation techniques can help to reveal motion principles in plants and to integrate the underlying mechanisms in flexible kinetic structures. By using three case studies, the authors will present key motion principles and discuss their scaling, distortion, and optimization. Finally, the acquired knowledge on bio-inspired kinetic structures will be applied to a representative application in architecture, in this case as flexible shading devices for double curved facades. Plant movements.Kinetic structures.Biomimetics.Facade shading.Compliant mechanisms.

Zusammenfassung

This paper discusses form-finding and simulation strategies for form- and bending-active hybrid structures. The interaction of tension in the surface and bending in beam elements leads to a complex form-finding question in which the boundary conditions for the membrane are nonlinear; they deform as a result of the membrane pre- stress. After a general introduction of form- and bending-active hybrid structures the form-finding question is discussed by introducing a numerical approach in FEM as well as through the discussion of realised projects.

Zusammenfassung

Jörg Schlaich setzt sich für eine ganzheitliche Qualität im Ingenieurbau ein. Das Prinzip Leichtbau ist dabei die zentrale Richtschnur seines Entwerfens. Leichtbau ist für ihn nicht Selbstzweck, sondern hat eine soziale, ökologische und kulturelle Bedeutung. Sozial, weil eine feingliedrige Konstruktion eine hohe Wertschöpfung für Planung und Herstellung generiert, ökologisch, weil ein geringer Materialeinsatz Ressourcen spart und kulturell, weil eine dem Kraftfluss folgende Form zeitlosen Gestaltungsprinzipien folgt. Zu seinem Selbstverständnis als kulturell verantwortlicher Ingenieur gehört auch die Verankerung in der Bau‐ und Konstruktionsgeschichte. Viele seiner Entwürfe knüpfen an Ansätze großer Wegbereiter des Ingenieurbaus an, interpretieren diese aber völlig neu und überführen sie in Konstruktionen höchster Eleganz. Wie werden nun heute die Ansätze von Jörg Schlaich zum Leichtbau aufgegriffen, wie werden sie weiterentwickelt und welche Diskussionen stoßen sie an? Stellvertretend für die vielen Kolleginnen und Kollegen, die ihre prägenden beruflichen Impulse Jörg Schlaich und seinem Umfeld verdanken, möchten wir dies an eigenen Projekten diskutieren.

Zusammenfassung

The paper presents experimental work to determine the load-bearing capacity, strain responses up to failure, and failure mode of pultruded carbon fiber–reinforced polymer (CFRP) strips with different deviation saddle geometries. Several tests with different deviation angles and deviation saddle radii were carried out. The results show that the tensile strength of the CFRP strip is reduced significantly by deviation, even if the deviation radius is comparatively large in relation to the thickness of the CFRP strips. Further tests were carried out to determine the influence of other important parameters on the load-bearing capacity of the strip such as surface properties of the saddle. With the help of a polyethylene layer (PE-HD) between the CFRP strip and the deviation saddle, friction could be reduced. This leads to an increase in the breaking strength of the CFRP strip. The effect of these parameters on the load-bearing capacity of the CFRP strip is presented in this article.

Zusammenfassung

In this paper the authors present research into an integrative computational design methodology for the design and robotic implementation of fibre-composite systems. The proposed approach is based on the concurrent and reciprocal integration of biological analysis, material design, structural analysis, and the constraints of robotic filament winding within a coherent computational design process. A particular focus is set on the development of specific tools and solvers for the generation, simulation and optimization of the fibre layout and their feedback into the global morphology of the system. The methodology demonstrates how fibre reinforced composites can be arranged and processed in order to meet the specific requirements of architectural design and building construction. This was further tested through the design and fabrication of a full-scale architectural prototype.

Zusammenfassung

Während eines Forschungsprojektes wurde ein neuer thermoplastischer Werkstoff für Fassadenbekleidungen entwickelt, der zu über 90 % aus nachwachsenden Rohstoffen besteht. Die recyclebare Biokunststoffplatte kann als Fassaden- und Innenwandbekleidung ebener oder frei geformter Innen- und Außenwände eingesetzt werden. Sie erfüllt die üblichen Anforderungen, die hinsichtlich Dauerhaftigkeit und Flammschutz an Baustoffe gestellt werden. Ziel des am Stuttgarter Institut für Tragkonstruktionen und Konstruktives Entwerfen (ITKE) durchgeführten Forschungsprojektes war, ein möglichst nachhaltiges und dennoch langlebiges Baumaterial zu entwickeln. Der Anteil erdölbasierter Komponenten und Additive sollte dabei gering gehalten werden. Das Institut für Siedlungswasserbau, Wassergüte- und Abfallwirtschaft (ISWA) übernahm die ökobilanzielle Bewertung, ermittelt wurde auch die Beständigkeit des Materials gegenüber mikrobiellem Abbau.

Zusammenfassung

Aerogelhaltiger Leichtbeton weist als gefügedichtes Material eine signifikant verbesserte Wärmedämmung gegenüber luftgedämmten Leichtbetonmaterialien auf. Durch eine gezielte Beeinflussung der Betonkomponenten zu einer höheren Packungsdichte lassen sich auch die Festigkeitseigenschaften positiv beeinflussen, sodass das Material sowohl eine hervorragende Dämmwirkung als auch eine ausreichende Tragfähigkeit aufweist. Der Aufsatz beschreibt die Materialentwicklung und experimentell ermittelte Materialparameter.

Zusammenfassung

Der von SOMA Architecture aus Wien, Österreich entworfene Themenpavillon “One Ocean” ist eines der wichtigsten Gebäude der Expo 2012 in Yeosu, Korea. Die dem Expo‐Gelände und dem Haupteingang zugewandte Seite ist von einer kiemenartigen, mit LED bestückten beweglichen Medienfassade geprägt. Sie stellt einen gestalterischen Bezug zum Meer her und ermöglicht die Lichtsteuerung des Gebäudes. Grundlage der Entwicklung der kinetischen Fassade war die Analyse natürlicher Bewegungsprinzipien. Die Verwendung von glasfaserverstärkten Kunststoffen (GfK) erlaubt große reversible elastische Verformungen und ermöglicht somit eine komplett neue Interpretation wandelbarer Strukturen.

Zusammenfassung

In the current paper the authors present a biomimetic design methodology based on the analysis of the Echinoids (sea urchin and sand dollar) and the transfer of its structural morphology into a built full-scale prototype. In the first part, an efficient wood jointing technique for planar sheets of wood through novel robotically fabricated finger-joints is introduced together with an investigation of the biological principles of plate structures and their mechanical features. Subsequently, the identified structural principles are translated and verified with the aid of a Finite Element Model, as well as a generative design system incorporating the rules and constraints of fabrication. The paper concludes with the presentation of a full-scale biomimetic prototype which integrates these morphological and mechanical principles to achieve an efficient and high-performing lightweight structure.

Zusammenfassung

The introduction of computational design processes and particularly of computer‐aided fabrication methods recast roles across the design team. As Jan Knippers , founding partner of Knippers Helbig Advanced Engineering and Head of the Institute of Building Structures and Structural Design (ITKE) at the University of Stuttgart explains, it offers structural engineers a unique opportunity: the potential to break through the barriers of conventional model thinking (thinking in discrete typologies) and to embrace process design and new forms of interaction.

Zusammenfassung

Bending-active structures are composed of curved beam or shell elements which base their geometry on the elastic deformation of an initially straight or planar configuration. In bending-active structures the moment of inertia has a direct influence on the residual stress and is therefore limited by a given minimal curvature in the system and the permissible bending stress capacities of the chosen material. These interdependencies may lead to a scaling issue that limit bending-active structures to a certain size range. This range may be widened if the system's reliance on elastic stiffness is compensated by other stiffening factors such as coupling of structural elements and stress stiffening effects. This paper will analyse the scaling effects in bending-active structures. Some basic systems are studied by means of dimensional analysis and FEM parameter studies to clarify at which power each influencing factor effects scaling. Based on these findings some more complex structures are studied for their scalability. This will offer the basis for some more general conclusions.

Zusammenfassung

In the current paper, the authors developed two different numerical methods for fibre reinforced polymers. The first method deals with the simulation of an innovative manufacturing process based on filament winding for glass and carbon fibre reinforced polymers. The second developed numerical method aims at modelling a high level of material complexity and allowing reciprocal confrontation with a geometric differentiated global structure. The developed numerical techniques served as a basis for the design and implementation of a Pavilion built on the campus of the University of Stuttgart in 2012 and could thus be tested and proved.

Zusammenfassung

In this paper structures that actively use bending as a self-forming process are reviewed. By bringing together important material developments and various historical as well as recently built samples of such structures, the aim is to show coherences in their design approach, structural systems and behaviour. Different approaches to bending-active structures are defined and described. By making this work accessible and categorising it, this paper aims to contribute to an emerging development. Adifferentiation of such structures is suggested based on their design approaches. Three such approaches are differentiated: the behaviour based approach, the geometry based approach and current research that seeks to integrate the two. In this paper the nature of these approaches and some important project samples are discussed.

Zusammenfassung

This paper will focus on how the emerging scientific discipline of biomimetics can bring new insights into the field of architecture. An analysis of both architectural and biological methodologies will show important aspects connecting these two. The foundation of this paper is a case study of convertible structures based on elastic plant movements.

Zusammenfassung

Material behaviour computes form. In the physical world, material form is always inseparably connected to internal constraints and external forces; in the virtual space of digital design, though, form and force are usually treated as separate entities – divided into processes of geometric form generation and subsequent engineering simulation. Using the example of the interdisciplinary ICD/ITKE Research Pavilion, constructed at the University of Stuttgart in 2010, Moritz Fleischmann, Jan Knippers, Julian Lienhard, Achim Menges and Simon Schleicher explain how feedback between computational design, advanced simulation and robotic fabrication expands the design space towards previously unexplored architectural possibilities.

Zusammenfassung

This paper presents a novel biomimetic approach to the kinematics of deployable systems for architectural purposes. Elastic deformation of the entire structure replaces the need for local hinges. This change becomes possible by using fibre-reinforced polymers (FRP) such as glass fibre reinforced polymer (GFRP) that can combine high tensile strength with low bending stiffness, thus offering a large range of calibrated elastic deformations. The employment of elasticity within a structure facilitates not only the generation of complex geometries, but also takes the design space a step further by creating elastic kinetic structures, here referred to as pliable structures. In this paper, the authors give an insight into the abstraction strategies used to derive elastic kinetics from plants, which show a clear interrelation of form, actuation and kinematics. Thereby, the focus will be on form-finding and simulation methods which have been adopted to generate a biomimetic principle which is patented under the name Flectofin®. This bio inspired hingeless flapping device is inspired by the valvular pollination mechanism that was derived and abstracted from the kinematics found in the Bird-Of-Paradise flower (Strelitzia reginae, Strelitziaceae).

Zusammenfassung

Die Herstellung doppelt gekrümmter Glaselemente mittels Kaltverformens, wie sie auf der glasstec 2010 vorgestellt wurden, ist vielversprechend für die Verwendung für Ganzglas‐Schalenkonstruktionen, deren optische und technische Qualität auf die Ansprüche der Architektur nach hochtransparenten, sanft gekrümmten Formen reagiert. Die Ergebnisse der Untersuchung von Formgebungs‐ und Materialeigenschaften der kaltgekrümmten Scheiben ermöglichten die Erarbeitung und Vorauswahl entsprechender doppelt gekrümmter Schalengeometrien. Charakteristische Grundformen sind dann Parameterstudien und Sensibilitätsanalysen zur Ermittlung des Tragverhaltens abhängig von Fügung, Lagerung und Einteilung unterzogen worden. Antiklastische Geometrien haben sich dabei als besonders interessant herausgestellt.

Zusammenfassung

In Friedberg (Hessen) wurde im Juli 2008 erstmals in Deutschland eine Straßenbrücke unter Verwendung von glasfaserverstärktem Kunststoff (GFK) fertig gestellt. Das Bauwerk überspannt mit 27 m die Bundesstraße B 3a bei der Stadt Friedberg (Hessen) und wurde in Stahl‐GFK‐Verbundbauweise realisiert. Die hohe Dauerhaftigkeit des neuen Werkstoffs und die zügige Montage der Brücke waren die entscheidenden Gründe pro GFK. In den letzten Jahren wurden in den USA, Japan und auch in Europa einige Leichtbaubrücken mit faserverstärkten Kunststoffen realisiert. Dabei konnten wertvolle Erfahrungen zum Bau und Betrieb gesammelt und die Leistungsfähigkeit von Verbundwerkstoffen unter Beweis gestellt werden. Die Brücke in Friedberg geht über diese Vorbilder hinaus, indem hier erstmals die Verbundwirkung zwischen der GFK‐Fahrbahn und dem Haupttragwerk aus Stahl berücksichtigt wird. Außerdem wurde konsequent der Ansatz eines wartungsarmen und langlebigen Bauwerks verfolgt, indem auf Lager und Fahrbahnübergänge verzichtet wurde.

Zusammenfassung

Kohlenstofffaserverstärkter Kunststoff (CFK) besitzt eine Reihe von ausgezeichneten Eigenschaften mit weitreichenden Anwendungsmöglichkeiten im konstruktiven Ingenieurbau. So werden schon seit einigen Jahren CFK‐Lamellen für die Instandsetzung und nachträgliche Verstärkung von Bauteilen aus Stahlbeton eingesetzt. Solche Lamellen könnten auch als freie Spannglieder, z. B. für extern vorgespannte Stahlbetonbrücken oder für unterspannte Decken im Hochbau, Verwendung finden. Die Empfindlichkeit von Kohlestofffaserverstärktem Kunststoff für Beanspruchungen durch Querpressungen macht jedoch die konstruktive Gestaltung der Endverankerung und der Umlenkung auf einem Sattel schwierig. Für die Endverankerung liegen bereits Ansätze von verschiedenen Forschungseinrichtungen vor. In diesem Aufsatz werden die Ergebnisse von Versuchen zur Ermittlung des Einflusses einer Umlenkung auf die Bruchlast von CFK‐Lamellen veröffentlicht.

Zusammenfassung

Frei geformte Gitterschalen aus Stahl sind in der zeitgenössischen Architektur weit verbreitet. Computergesteuerte Planungs‐ und Fertigungswerkzeuge ermöglichen Konstruktionen, die vor wenigen Jahren noch undenkbar gewesen wären. Aber wie wird eine frei geformte 3D‐Geometrie in eine gebaute Struktur überführt, ohne dass dabei die architektonische Vision einer elegant geformten Gebäudehülle verlorengeht? Dazu ist von der Formgenerierung bis zur Montage auf der Baustelle eine durchgängige Prozesskette erforderlich, in der der Tragwerksplaner als Schnittstelle zwischen den ästhetischen Ambitionen des Architekten, den technischen Zwängen der Fertigung und den finanziellen Möglichkeiten des Bauherren eine zentrale Rolle einnimmt. In diesem Aufsatz wird am Beispiel von zwei verglasten Gitterschalen gezeigt, wie frei geformte 3D‐Geometrien neue Abläufe bei der Planung erfordern und sich neue Betätigungsfelder für Tragwerksplaner eröffnen.

Zusammenfassung

The recent completions of free-form spatial structures provide us a very attractive form. To realize such an extraordinary shape, it is absolutely necessary that the connector systems have to be investigated the characteristics of the systems and analyzed with a practicable method. In this context, this research consists of not only literature research but also numerical analysis with selected connector systems, which was adopted in real free-form spatial structures. For numerical analysis, especially, finite element analysis (FEA) is performed with a various test parameter using a commercial program ANSYS. Consequently, the general characteristics of node connectors the moment-rotation-curves are presented by considering a large deformation effect as well as a multi-linear material properties.

Zusammenfassung

The appearance of many Glass Fiber Reinforced Plastic (GFRP) constructions look like ordinary steel construction, because GFRP has been imitated by the same way with the traditional steel's cross section as well as connection system. In terms of detachable connection, there was not enough appropriate option of GFRP connection, such as a traditional bolt connection for steel and wood structures. Most of all, from material characteristic of GFRP related to the deficient ductility, the shearstress principle of GFRP s not proper for the material property, which causes ineffective and not economic application of material. With this research problem, the innovative and detachable onnection system, which is more considered with appropriate material characteristic for FRP, is developed. Not only short time but also long time research with various connection variations is carried out.

Zusammenfassung

Auf der glasstec 2006 in Düsseldorf, der weltweit größten Messe der glaserzeugenden und glasverarbeitenden Industrie, wurde von der Firma Seele eine Ganzglastreppe mit einer freien Spannweite von sieben Metern errichtet. Die beiden tragenden Wangen bestehen aus jeweils einer mehrlagigen Floatglasscheibe ohne Stoß. Neben der großen Spannweite der Glasscheiben ist vor allem die Verwendung einer neuartigen Klebetechnik mittels hochtransparenter SGP (SentryGlas® Plus)-Folien bemerkenswert. Im Mittelpunkt dieses Aufsatzes stehen das statische Konzept der Treppe sowie die Ausführung und Bemessung der Klebeverbindungen.

Zusammenfassung

Currently, the structural material, namely glass fiber reinforced polymer (GFRP) is focused on innovative structure due to lightness, excellent workability and noncorrosive characteristics, etc. However, the lack of GFRP connection technology produces only an imitation of steel and wood structures. This uses univentive design principles as well as unsuitable material applications, causes tons of surplus of materials to be wasted, and results in uneconomical structures, because the characteristics between steel and GFRP are completely different. Thus, this research develops the new, innovative GFRP connection system with considerations of the characteristics of GFRP and adopts it to a mobile und modular membrane pavilion.

Zusammenfassung

Mit dem neuen Kaufhaus Peek und Cloppenburg ist ein Bau von herausragender architektonischer Qualität mitten im Herzen der Kölner Altstadt entstanden. Seine Fassade, über die in diesem Aufsatz berichtet wird, war in vielfacher Hinsicht eine besondere Herausforderung für die Tragwerksplanung. Dies betrifft die komplexe Geometrie, die Lagerung auf dem Rohbau vor allem aber die ungewöhnliche und neuartige Kombination der Werkstoffe Stahl und Holz. Aufgelöste vertikale Holzbinder und horizontale Stahlrohre bilden mit diagonalen Stahlseilen eine freitragende Stabschale. Dazu mußten zahlreiche Konstruktionsdetails, insbesondere die Holzverbinder, erstmals gelöst werden.

Zusammenfassung

Grid shells exhibit different modes of stability failure. This paper explains some parameters influencing the failure load of domes and barrel vaults and makes suggestions for the imperfection shape which has to be assumed in an analysis. All computations are carried out with a commercial FE-program.

Zusammenfassung

A fjord of the Baltic Sea divides the centre of the City of Kiel. To provide a pedestrian crossing that allows passage of ships, a folding cable-stayed bridge was built. Its unusual folding mechanism was proposed not only to ensure a safe and robust operation, but also to provide a visual and technical attraction. The deck folds at three hinges by the continuous rotation of a pair of single-speed winches, to which all cable drums are connected.

Zusammenfassung

Der Beitrag beschreibt den Einfluß von Stablänge, Stabsteifigkeit und dem Stich-zu-Spannweiten-Verhältnis auf die erreichbare Traglast von Stabschalen. Daneben werden Überlegungen zur Wahl der rechnerischen Ersatzimperfektionen angestellt. Diese sind nicht nur für die Stabschalen von Interesse, sondern lassen sich auf die Berechnung von beliebigen stabilitätsgefährdeten Strukturen übertragen.

Zusammenfassung

A mixed/hybrid FE formulation for the solution of elasto-viscoplastic problems under dynamic loading conditions is presented. The constitutive equations under considerations are those of Chaboche. The spatially semi-discretized system of ordinary differential equations is numerically integrated in time by means of a midpoint type algorithm. A layer-model is developed which enables the application of the proposed methods in shell or plate theory. Numerical examples demonstrate the efficiency of the proposed method.

Zusammenfassung

A mixed/hybrid FE formulation for the solution of elasto-viscoplastic problems is presented. The spatially semi- discretized system of ordinary differential equations is numerically integrated in time by means of a midpoint type algorithm. Stability considerations are discussed and conditions for its maintenance are established. Illustrative numerical examples demonstrate the ability of the proposed method to reproduce elasto-viscoplastic behaviour. Comparison with known results is also made.

Zusammenfassung

L'uso di materie plastiche e membrane è abbastanza recenti nell'architettura. Dopo un attento esame dei materiali sintetici in uso nelle costruzioni, vengono presentati i semilavorati rinforzati con fibre, membrane e membrane tessili idonei per l'impiego nell'architettura. L'impiego dei semilavorati viene presentato in modo pratico-operativo con una carrellata di dettagli che presentano soluzioni che non tengono solo conto del carattere tecnologico del materiale ma anche del ruolo nella fisica costruttiva negli involucri multistrati. Inoltre i casi di studio sono stati scelti per rappresentare le molteplici possibilità di utilizzo e integrazione di questi materiali nella progettazione architettonica moderna.

Zusammenfassung

Whether it be as translucent sheets, broadly stretched membranes, and inflated foil cushions or in graceful, organic curves, architecture today is utilizing plastics in the most disparate forms and for a wide variety of purposes. Innovative technical developments are constantly improving its material properties; at the same time, there is a growing new awareness of its potential as a construction material. While plastics used to be employed primarily as an inexpensive variant on traditional building materials, they are increasingly regarded in the construction world today as a serious and viable alternative, be it as supporting structures, roofs, facades, or elements of interior design and decoration. Thanks in large part to this inherent self-sufficiency, plastics are currently enjoying an unprecedented surge in popularity, even among the international architectural avant-garde – as multiwall sheets or corrugated, fiber-reinforced panels, or as filling between glass panes. And the new generation of ecological bioplastics also pays tribute to the debate on sustainability, ridding plastics of their lingering reputation as environmental offenders. From the history of plastics and membranes in architecture to their material properties and requirements in construction and design, the Plastics and Membranes Construction Manual cuts to the chase, providing the kind of solid and comprehensive overview of the subject that readers have come to expect from the Im DETAIL series. Selected project examples round off the reference work and make it indispensable for the day-to-day life of the professional planner and for every architecture library.

Zusammenfassung

Grundlagen des Bauens mit synthetischen Werkstoffen Von transparent bis transluzent – neue Konstruktionsmöglichkeiten mit einem vielseitigen Material Ob als transluzente Platten, weit gespannte Membranen, luftgefülltes Folienkissen oder in organisch geschwungener Gestalt: In den unterschiedlichsten Formen und Anwendungsbereichen finden Kunststoffe Verwendung in der Architektur. Innovative technische Entwicklungen verbessern stetig seine Materialeigenschaften. Kunststoffe sind heute im Bauwesen eine ernstzunehmende Alternative, sei es als Tragkonstruktion, Dach, Fassade oder Inneneinrichtung. Der »Atlas Kunststoffe + Membranen« kehrt zu den Basics der Reihe zurück, indem er sich einem einzelnen Baustoff widmet. Von den Werkstoffeigenschaften bis hin zu Anforderungen an Entwurf und Konstruktion bringt er in gewohnter DETAIL-Qualität fundiertes und umfassendes Fachwissen auf den Punkt. Ausgewählte Projektbeispiele runden das Nachschlagewerk ab und machen es unabdingbar für den Planungsalltag. - Geschichtliche Entwicklung von Kunststoffen und Membranen in der Architektur - Umfassende Grundlagenvermittlung zu Herstellung, Verarbeitung und Anwendung - Präzise Materialbeschreibung zu Werkstoffen und Halbzeugen - Bauphysikalische Eigenschaften und Umwelteinwirkungen - Formfindung und Berechnung von Kunststofftragwerken und Membranen - Erstmals nach neuestem Forschungsstand komplett zusammengestellte Übersicht von Leitdetails

Zusammenfassung

Coreless filament winding (CFW) is an advancement of industrial filamentwinding for architectural applications. In this process, the formwork is reduced to anabsolute minimum, allowing the fibers to span freely in space between anchor points.Using carbon and glass fibers with a resin matrix, it exhibits high potential for light-weight, material efficient building elements. While previous research demonstrated itsapplicability in shell, roof and long-span structures, the potential in using this methodfor multi-story wall and slab systems has not been thoroughly investigated. This paperelaborates on methods to develop structural wall components built entirely of carbonand glass fiber composite, which are specifically tailored to meet the requirementsof multi-story construction in architecture. A computational design method basedon tangent-based approximation was developed to generate bespoke fiber patternsand openings, allowing the wall components to act as load-bearing elements. Thisfacilitates the generation of a multitude of pattern variations which can be adaptedto axisymmetric and asymmetric boundary conditions. Structural performance of thebuilding elements is evaluated throughout the design process by means of finite ele-ment analysis establishing a feedback loop between design, robotic fabrication andstructural evaluation and informing the optimisation of the wall geometry and fiberlayup. The developed methods were successfully applied in the design and fabricationof a multistory fiber installation exhibited at the 17th Architectural Biennale in Venice.It demonstrates the potential of coreless wound load-adapted fibrous walls as archi-tectural building components leveraging integrative computational design, structuralengineering and robotic prefabrication.

Zusammenfassung

Curved, surface-active, shell structures are known for material efficiency and slenderness but typically require complex manufacturing and formwork in combination with intricate on-site construction processes. The presented research proposes an alternative approach: a self-shaping building system for deploying lightweight, curved surface structures made from timber. The system uses the inherent hygromorphic properties of wood which naturally shrinks through drying. This anisotropic shape change is embedded into large-scale bilayer sheets - produced, machined, and shingle clad in a flat state with their later curved shape and connection detailing physically programmed within the material build-ups. When placed on-site, these sheets actuate through air drying to a final curved and interlocked geometry. Geometrically the structure is integratively designed from variable single curved surfaces using key material parameters (end grain angle and moisture content change) within a material stock, in relation to both the self-shaping and the final structural configuration. Each surface is modeled in the curved state using a board specific algorithmic calculation of curvature potential in parallel to a flat fabrication model. Emphasis is placed on investment in early-stage planning and intelligent material arrangement as a method to produce useful curvature. As a result, the curved shell shapes and interlocks without formwork or external mechanical force, with little onsite work. The outcome is a lightweight, longspan roof structure built from single curved wood surfaces with a thin cross-laminated build up. The project demonstrates a tangible new method of low impact, light touch self-construction and an ecologically effective use of material and geometry.

Zusammenfassung

This paper proposes an interactive computational approach for designing the layout of timber column-slab structures in a material-saving and structural-performance aware manner. The generated column slab layout meets the serviceability limit state deflection criteria by integrating gradient-based optimization within an agent system approach. This was achieved by extending the ABxM framework with an interactive design framework termed Timber Column Slab (TCS) solver. This solver is underpinned by three data structures: Firstly, an agent system representing a column-slab system for layout exploration. The finite element (FE) model that computes the slab’s nodal displacements, which enables rapid serviceability checks at each agent-system update in a real-time loop. With the TCS extension, the agent-based model uses the numerical analysis results to refine the decision of the adaptive agents. The real-time interaction built within the agent-based model is responsible for the live user guidance and design software integration. The proposed methodology has been built with multiple scientific stacks and encapsulated into an open-source framework in a C# environment. The developed method is tested on a wide range of real building floor plans of different scales and typologies, demonstrating how effective it is compared to previous efforts.

Zusammenfassung

In recent years, the coreless filament winding (CFW) technique has gained attraction due to its capacity to effectively realize large-scale lightweight building components out of fibre-reinforced composites. However, the sequential nature of its filament- based production process imposes a series of design constraints that restrain the use of this technique in new typologies and applications. The current research introduces a novel shape optimisation-to-fabrication method that expands the scope of CFW to- wards the production of load-bearing components for slabs. A multi-stage workflow is proposed, integrating parametric design, shape optimisation, stress-driven mate- rial layup, and fabrication to ensure a high level of consistency between form and materialization. The research is presented in two phases. The first phase explores the use of shape optimisation to comprehend the underlying logic of shell forms capable of performing under the specific requirements of the slab scenario. The sec- ond phase integrates the inherent conditions of the material, formwork system, and robotic filament winding process into a seamless design-to-manufacturing workflow. The research resulted in a 10.2 kg prototype of a slab load-bearing structure that withstood a load of 559 kg while spanning 2.7 m, demonstrating the effectiveness of the approach.

Zusammenfassung

Faserverbundwerkstoffe, auch als faserverstärkte Kunststoffe bezeichnet, haben wegen ihrer hervorragenden Werkstoffeigenschaften schon seit Langem einen festen Platz in der Luft‐ und Raumfahrttechnik, der Sportgeräte‐ und Automobilindustrie etc. Im Bauwesen sind sie noch selten, finden aber zunehmend Anwendung in Brücken, Fassaden, Windrädern oder als Verstärkung von Betonbauteilen. Der Beitrag gibt planenden Ingenieurinnen und Ingenieuren eine Zusammenstellung der Ausgangswerkstoffe, der Herstellungs‐ und Verarbeitungsverfahren, der bauaufsichtlich eingeführten technischen Regeln und zugelassenen Bauprodukte sowie der Bemessungskonzepte. Außerdem werden gebaute Beispiele gezeigt. Ziel ist es, den Vorteilen dieser Bauart, wie z. B. geringes Eigengewicht bei hoher mechanischer Festigkeit und Steifigkeit, Frost‐Tausalzbeständigkeit, niedrige thermische Leitfähigkeit, freie Formbarkeit etc. ein breiteres Anwendungsspektrum zu ermöglichen.

Zusammenfassung

In architectural research, pavilions play a special role because, as temporary structures, they present an opportunity to investigate specific issues without having to fulfill all requirements for permanent buildings. The findings resulting from this investigation can then be utilized in the design and implementation of permanent buildings. In this contribution we describe the context in which the Rosenstein Timber Pavilion was created, and the special issues that were investigated in the project, as well as the knowledge gained from it. In addition, we provide an outlook on other current research topics in the field of segmented timber shells and their application in architecture.

Zusammenfassung

Der spannende und vielseitige Leistungsumfang der Ingenieure im Bauwesen wird in der Öffentlichkeit selten als solcher wahrgenommen. Dabei ist die Bauwirtschaft nicht nur eine der Schlüsselindustrien in wirtschaftlicher, sondern auch in sozialer bzw. gesellschaftlicher Hinsicht: Ohne Bauten und Infrastruktur ist unser modernes Leben schlichtweg unvorstellbar. Das Ziel der Publikation ist es daher, den Beruf des Ingenieurs – stellvertretend für die gesamte Branche – so darzustellen, wie er ist: faszinierend, kreativ, umfassend und innovativ.Ingenieurpersönlichkeiten und deren Innovationen werden dazu vor dem Hintergrund der jeweiligen gesellschaftlichen, wirtschaftlichen und politischen Einflüsse dargestellt – von der Historie kommend mit dem Schwerpunkt auf aktuellen Projekten.

Zusammenfassung

Pflanzen besitzen weder Muskeln noch „klassische“ lokale Gelenke – und können sich dennoch bewegen. Im Laufe der Evolution sind effiziente Bewegungsmechanismen und ästhetische Bewegungsformen entstanden. Aus diesem „Angebot“ der Botanik schöpfen Architekten und Ingenieure in Zusammenarbeit mit Biomechanikern Inspiration für die Entwicklung neuartiger Verschattungssysteme für moderne Gebäude.

Zusammenfassung

Plant movements can inspire deployable systems for architectural purposes which can be regarded as ideal solutions combining resilient bio-inspired functionality with elegant natural motion. Here, we first give a concise overview of various compliant mechanisms existing in technics and in plants. Then we describe two case studies from our current joint research project among biologists, architects, construction engineers and materials scientists where the aesthetic movements of such role models from the plant kingdom are analysed, abstracted and implemented in bioinspired technical structures for sustainable architecture. Both examples are based on fast snapping movements of traps of carnivorous plants. The Waterwheel plant (Aldrovanda vesiculosa) captures prey underwater and the Venus flytrap (Dionaea muscipula) snaps in the air. We present results on the motion principles gained by quantitative biomechanical and functional-morphological analyses as well as their simulation and abstraction by using e.g. Finite Element Methods. The Aldrovanda mechanism was successfully translated into a similarly aesthetic and functional technical structure, named Flectofold, which exists in a prototype state. The Flectofold can be used as a façade shading element for complex curved surfaces as existing in modern architecture.

Zusammenfassung

Aiming to support the current research on bending-active plate structures, this paper discusses the topic of form-finding and form-conversion and presents examples to illustrate the formal and structural potential of these design strategies. Following a short introduction into the topic, the authors reflect on the specific challenges related to the design of bending-active plate structures. While previous research has mainly focussed on a bottom-up approach whereby the plates first were specified as basic building blocks and the global shape of the structure resulted from their interaction, the main emphasis of this paper lies on a possible top-down approach by form-conversion. Here, the design process starts with a given shape and uses surface tiling and selective mesh subdivision to inform the geometrical and structural characteristics of the plates needed to assemble the desired shape. This new concept entails some constraints, and the paper therefore provides an overview of the basic geometries and mechanics that can be created by following this approach. Finally, to better demonstrate the innovative potential of this top-down approach to the design of bending-active plate structures, the authors present two built case studies, each of which is a proof of the concept that pushes the topic of form-conversion in a unique way. While the first one takes advantage of translating a given shape into a self-supporting weave pattern, the second case study gains significant structural stability by translating a given form into a multi-layered plate construction.

Zusammenfassung

Seit 2012 werden am ITKE (Universität Stuttgart) Einsatzmöglichkeiten faseroptischer Sensoren mit Bragg‐Gittern zur Spannungsmessung auf Glasoberflächen und in Glaslaminaten erforscht, wofür die Sensoren aufgrund ihres geringen Durchmessers (< 0,2 mm), ihrer Robustheit, der Aufnahme mehrerer Sensoren auf einer Faser und der Verwendung eines Lasermesssignals besonders ge‐eignet sind. Die Entwicklung einer transparenten, autoklavgeeigneten Verklebung der Sensorfaser mittels Versuchen, numerischen und analytischen Modellen hat die Anwendung zum kontinuierlichen Echtzeit‐Spannungsmonitoring in laminationsgebogenen Gläsern ermöglicht. Das Potential konnte mittels eines begehbaren, sensitiven Glasbogens auf der glasstec 2014 gezeigt werden.

Zusammenfassung

Concrete double-curved shell constructions have been used in architectural design and building constructions since the beginning of the twentieth century. Although monolithic shells show a high stiffness as their geometry transfers loads through membrane forces, they have been mostly replaced by the more cost-efficient lattice systems. As lattice systems are covered by planar glass or metal panes, they neither reach the structural efficiency of monolithic shells, nor is their architectural elegance reflected in a continuous curvature. The shells of sand dollars’ – highly adapted sea urchins – combine a modular and multi-plated shell with a flexible, curved as well as smooth design of a monolithic construction. The single elements of the sand dollars’ skeleton are connected by calcite protrusions and can be additionally supported by organic fibres. The structural efficiency of the sea urchin’s skeleton and the principles behind them can be used for innovations in engineering sciences and architectural design while, at the same time, they can be used to illustrate the biological adaptations of these ecologically important animals within their environments. The structure of the sand dollar’s shell is investigated using modern as well as established imaging techniques such as x-ray micro-computed tomography (μCT), scanning electron microscopy and various optical imaging techniques. 3D models generated by μCT scans are the basis for Finite Element Analysis of the sand dollar’s shell to identify possible structural principles and to analyse their structural behaviour. The gained insights of the sand dollar’s mechanical properties can then be used for improving the state-of-the-art techniques of engineering sciences and architectural design.

Zusammenfassung

In architecture and construction engineering, a vast number of connections and branched columns in frame structures exist that are exposed to high static and dynamic loads. The manufacture of many of these elaborate structures is both time-consuming and costly. Industry has no solution for cost-effectively producing aesthetic and mechanically stable branched columns. This challenge is addressed by the development of branched structures inspired by branched biological concept generators such as Schefflera arboricola. Here, we present methodological approaches allowing the reconstruction of the outer shape and inner structure of complex branching regions, such as in S. arboricola, by using and combining three-dimensional-image stacking of histological thin sections, micro-computer-tomography (μCT) imaging and laser scanning. Computer-aided design (CAD) and Finite Element (FE) models of such structures can then be produced that not only help to provide a better understanding of the functional morphology and biomechanics of the biological concept generator, but also render the basis for the intended biomimetic transfer to branched columns consisting of a braided hull filled with concrete. The current project results are mainly based on the analysis of S. arboricola branching and the results of a previous research project (SPP 1420) in which biomimetic branched fibre-reinforced plastic (FRP) columns inspired by the branching structure of Dracaena were produced. Currently a biomimetic hull geometry that can be manufactured industrially is developed. Initially, branched FRPs based on triaxial braids with readily adjustable mechanical properties are filled with concrete and thus shall achieve sufficient mechanical properties for application and cost-effective fabrication in the building industry.

Zusammenfassung

The research presented in this paper pursues the development and construction of a robotically fabricated, lightweight timber plate system through a biologically informed, integrative computational design method. In the first part of the paper, the authors give an overview of their approach starting with the description of the biological role model and its technical abstraction, moving on to discuss the computational modelling approach that integrates relevant aspects of biomimetics, robotic fabrication and structural design. As part of the validation of the research, a full-scale, fully enclosed, insulated and waterproof building prototype has been developed and realized: The first building featuring a robotically fabricated primary structure made of beech plywood. Subsequently, the methods and results of a geodetic evaluation of the fabrication process are presented. Finally, as the close collaboration between architects, structural and geodetic engineers, and timber fabricators is integral to the process, the architectural and structural potentials of such integrative design processes are discussed.

Zusammenfassung

The paper presents a bottom-up design process based on the transfer of biomimetic design principles and digital fabrication strategies for modular fibre-based structures, as demonstrated on a full-scale prototype pavilion. Following the analysis of the structural principles of the beetle elytra, the material differentiation and the morphologic principles of the biological role model are transferred into design and fabrication strategies. Simultaneously, developments of a coreless robotic winding method for glass and carbon fibre reinforced composite elements are incorporated into the design process. The computational set-up developed for the entire workflow is presented, showing the integration of structural analysis with digital simulation, which enables the automatic generation of the robotic winding syntax for individually differentiated components. The investigations, simulation, fabrication and assembly process, which led to the realisation of a highly efficient lightweight architectural prototype, are explained in the current paper.

Zusammenfassung

Glas wird oft lastabtragend eingesetzt, wobei aus Gründen der Sicherheit und des Tragverhaltens Laminate zum Einsatz kommen. Insbesondere kalt gebogene, durch Lamination formstabilisierte Gläser sind ein zunehmend nachgefragtes Produkt. Herstellungsprozess und Nutzung führen in solchen Laminaten zu teils unbekannten Spannungen, welche die Aufnahme äußerer Einwirkungen begrenzen. Optische Messverfahren mit polarisiertem Licht erlauben keine Erfassung dieser Spannungen. Dünne, innen auf die Gläser geklebte faseroptische Sensoren stellen eine mögliche Lösung dar: In Versuchen an kalt gebogenen Gläsern wird gezeigt, dass optische Sensorik dem Laminationsprozess standhält und sich für kontinuierliche Dehnungsmessungen in Glaslaminaten eignet.

Zusammenfassung

Adaptive facades can greatly impact a building’s energy balance by responding to external climates and by regulating internal conditions. With the integration of solar energy harvesting components, they have the potential not only to reduce the energy loss of buildings but also to gain energy. This premise has been tested within the framework of bio-inspired compliant mechanisms for adaptive façade elements, developed at the University of Stuttgart. Due to the flexible kinematic behavior of bio-inspired adaptive architectural elements, an innovative and simple alternative to common, more complex applications of adaptive façade components is obtained. The research presented aims at establishing the environmental criteria that will lead to an improved energy performance of a building using elastically deformable, adaptive faҫade elements with integrated photovoltaics. Through simulations and physical testing, the influence of daylight, solar radiation, and the building´s thermal balance are evaluated. The findings of this research are showcased on an adaptive façade consisting of pneumatically actuated, glass fiber-reinforced plastic laminates with integrated photovoltaics, assembled at Botanical Garden in Freiburg, Germany. Relying on environmental sensing, this façade is able to adapt over time in response to solar conditions with the goal of finding the right balance between low-energy building operation, high indoor environmental quality, and high energy harvesting. This study provides a novel, integrative design method utilizing adaptive building envelopes that successfully react to varying environmental conditions in an energy-efficient and cost-effective manner.

Zusammenfassung

This paper presents a feedback-based computational method for the placement of columns in the early design phase of complex multi-story structures. The method integrates a circle packing algorithm, a spring system, and structural engineering simulations within a single script for the reciprocal and informed arrangement of columns in the space. While allowing the users to have an explorative approach, it empowers diverse potentials in multi-story constructions including additional cantilevering spaces around the boundary, increased spatial qualities with large span possibilities, multidirectional structural arrangements, and multi-purpose use of space. As a result, the developed algorithm allows for flexibility by leveraging the design possibilities of grid-based and irregular column arrangements and promotes the integration of structural and design-related constraints in the spatial organization of various building typologies.

Zusammenfassung

This paper discusses the architectural design potentials of a novel hollow timber slab building system for flexible and adaptive multi-storey timber building typologies. Current timber building systems are defined by their standardized nature, which limits most structures to unidirectional, rigid grids and limits designs to rectilinear layouts. At the same time, recent developments in computational design and digital fabrication open new possibilities to overcome these limitations. In this paper we present four building design applications of a new multi-directional slab building system that allows for a greater level of spatial flexibility and adaptability with free column placement and a tuned network of internal shear webs. These examples expand on previous work through the co-development of building design, skin, building system, and building service integration strategies for a long lifespan and changeable building program. The design applications illustrate open, reprogrammable floor plates that can support three different program states: office, residential, and mixed-use. Furthermore, the novel conceptual approaches to building service integration and the resulting slabs are compared to approaches more common in mass timber construction. Finally, we contextualize the study with related developments and discuss how computational and integrated design thinking could lead to a greater level of design freedom in timber construction and an increased applicability to more complex site conditions than in conventional masstimber construction

Zusammenfassung

Coreless filament winding (CFW) was developed in 2012 at the University of Stuttgart to reduce material waste during the fabrication of composite parts. This was achieved by diminishing the required formwork of state-of-the-art filament winding to discrete boundary frames. Then, impregnated fibers are wound between them, forming lightweight lattice structures. A series of pavilions at the University demonstrated the system's potential and enabled the transfer of CFW into practice, bringing along other engineering challenges, such as the requirement to prove structural integrity and safety. The BUGA Fibre Pavilion was the first long-span application using CFW. In this project, a series of full-scale structural tests successfully proved the structural capacity of the composite components. Maison Fibre expanded the research toward multi-story building systems and explored the combination of CFW components with timber plates as hybrid slabs. To improve the sustainability aspects of the system, the LivMatS Pavilion replaced the previously used carbon and glass fibers with natural fibers. This pavilion achieved different materiality, showing the potential of bio-composite filament wound structures. This paper describes and compares the design and engineering process in each system: long-span, hybrid slab, and natural fiber components, and reveals the potential and future research goals to achieve more sustainable building systems using CFW structures.

Zusammenfassung

The goal of this ongoing research is the development of a novel, digital, modular wood building system, which allows for open-plan, flexible spaces and bespoke architectural solutions. This paper presents a comparison of two new timber building systems for multi-storey construction. The building systems, one solid and one hollow, are developed using an integrative approach that considers structural, fabrication and assembly requirements in the system design process.

Zusammenfassung

This paper presents the development of an actively controlled shape changing surface-like structure, where geometric adaptivity is utilised by local elastic deformation on the component level. Besides the physical development of a proof of concept demonstrator, the research proposes a digital form-driving process, a computational workflow which allows the design and fast simulation of the shape changing structure, as well as the digital control of the actuation on the component level. The proposed material system consists of an initially flat surface, which is tessellated into single components based on a hexagonal grid. Each cell is comprised of a three-layer system, where a pneumatic cushion is placed in the middle of two bending active plates with strategic cut outs 1. In this way, each cell can be pneumatically actuated and therefore elastically deformed. The induced bending in the outer plates leads to a controlled change of area – the cells shrink or expand. By controlling this local behaviour within the global arrangement according to principle geometric rules 2 it is possible to achieve a controlled shape change from an initially flat surface to an anticlastic or synclastic geometric configuration. To design, simulate and control the shape change, the authors propose a digital form driving process. Here, the cells are abstracted and simplified into polygons, which can shrink and expand within a given range, according to the proposed physical system. This allows for the fast simulation of different actuation patterns and resulting geometric changes. The abstract values of shrinkage or expansion of each cell can be translated into pressure values and are used to control the pneumatic actuators in the physical demonstrator (figure 1).

Zusammenfassung

This paper presents an agent-based method for the design of complex timber structures. This method features a multi-level agent simulation, that relies on a feedback loop between agent systems and structural simulations that update the agent environment. Such an approach can usefully be applied for the design of variable density timber slab systems, where material arrangements based on structural, fabrication, and architectural boundary conditions are necessary. Such arrangements can lead to multi-directional spanning slabs that can accept pointwise supports in unique layouts. We discuss the implementation of such a method on the basis of the structural design of a pavilion-scale multi-storey testing setup. The presented method enables a more versatile approach to the design of multi-storey timber buildings, which should increase their applicability to a diverse range of building typologies.

Zusammenfassung

Funicular shells are known to be an efficient design paradigm for self-weight-driven structural surfaces 1. Nevertheless, the rules that govern funicularity offer a fairly constrained design spectrum, limiting the scope of application for these structures 2. The principle of corrugation has proven to be an effective approach to enable efficient structural performance in non-funicular thin shells 3. The research presented in this paper explores the use of corrugation methods for shells in the context of a computational and structural design workflow. As an extension to existing methods, the authors introduce work on Dynamic Corrugation, a strategy for increasing bending and buckling performance on non-funicular global designs by modulating the undulation of their surfaces according to bending stress distribution. The bending-driven dynamic corrugation method was developed during the Form and Structure seminar of the ITECH programme at the University of Stuttgart and was evaluated through the design of a non-funicular funnel shell in textile concrete. The method consists of a two-step Shape Optimization workflow that integrates NURBS-based surface generation with FEA and a Multi-Objective Genetic Algorithm (MOGA). In a first step of the design workflow, the initial design surface is analyzed to give its bending energy vector field. This field then serves as the source to generate a modulation curve passing through the areas of peak bending stresses. This curve then regulates the frequency, amplitude, and influence of local bending on the corrugation. The MOGA is given control over these variables and attempts to minimize both bending moment and displacements, offering a wide spectrum of performances and expressions along the emerging Pareto front. Simultaneously, the introduction of local curvature is evaluated on its capacity to improve the buckling resistance and to allow reductions in material thickness. The presented iterative approach is incorporated in a computational design framework. A series of Dynamic Corrugation-optimized shell samples are then compared with the initial non-corrugated design showing great structural (improved bending and buckling resistance), as well as economical and ecological (material savings) potential. Further, the expressive value of dynamically corrugated shells is deemed as a contribution to the aesthetic value of a design proposal for a small infrastructural building.

Zusammenfassung

Within the collaborative research center Transregio 141 ‘Biological Design and Integrative Structures. Analysis, Simulation and Implementation in Architecture’, the authors work in an interdisciplinary team composed of biologists, structural engineers, and textile engineers developing novel technical branchings as structural elements for architecture inspired by branchings in nature. Branchings are common in structures of plants and construction and have to fulfill structural demands in both fields. As resource efficiency is a vital factor allowing plants to resist competitive stress, beneficial load-bearing principles found in plants might, in an abstracted manner, also improve technical support constructions. To discover these principles, the biomechanics of selected plant branchings were investigated by FE-simulations. The observed principle of continuous fiber courses from the stem into the branch yields stiff and strong connections also favored in artificial joints. The key challenge is to produce technical branchings with a continuous fiber arrangement. This is enabled by a newly developed braiding process for branched structures. The design of the branched large-scale demonstrator at the Museum of Natural History in Stuttgart for the exhibition ‘baubionik’ (construction-bionics) reveals the potential for future architectural applications with individually variable knot geometries. The findings of the investigation mark a starting point for a novel braided concrete-fiber-reinforced plastic composite construction for branched supporting columns with both high aesthetical and load-bearing demands as a potential competitor for current construction methods of cast steel knots or labor-intensive welded steel pipe joints.

Zusammenfassung

In modern architecture branched supporting structures are increasingly used. Until now, these branched columns can only be produced in an extensive and cost-intensive way. A new concept made of fibre-reinforced plastic (FRP) serving as a formwork and a load-bearing hull for a concrete core makes it possible to produce a wide variety of different forms and geometries. To enable the potential of complex branched geometries, especially continuous load-confirming fibre arrangements over the entire braiding hull and large diameters, an advanced braiding technique to create triaxially braided preforms is required. This paper focuses on recent developments of an advanced braiding process to fabricate a multi-layered complex structural geometry on a 144 bobbins radial braiding machine and the adaptation of stationary threads until now regulated by spring force into ones operated electronically. With the new braiding technique, branched performs with triaxial braids were produced. Subsequent to impregnation with a thermosetting resin and annealing, the FRP-hull is poured with concrete. To evaluate a potential load increase of load capacity of the concrete core due to the confinement of FRP-hulls compression tests are conducted. In comparison to plain concrete specimens the mechanical parameters of fibrereinforced plastic-concrete-composites show a significant increase in compression strength.

Zusammenfassung

Within the collaborative research center Biological Design and Integrative Structures (CRC TRR 141), a research team of biologists, architects and engineers from Freiburg, Tübingen and Stuttgart is working on the development of biomimetic and bioinspired structures for implementation in architecture and building construction. One of the projects in this research center deals with the kinematics of planar, curved and corrugated plant surfaces as concept generators for deployable systems in architecture. It is an example for methods of engineering science at the interface between biology and architecture. The contribution will provide an insight into the process of analyzing the waterwheel plant Aldrovanda vesiculosa, a carnivorous plant that catches its prey by a quick closing movement of a snap trap consisting of two lobes attached to a midrib. At a first glance, the mechanism resembles the one of the famous Venus flytrap; however, it appears to be quite different from a mechanical point of view. In fact, a key aspect in the research presented here is the development of mechanical models and performing corresponding finite element analyses of the plant with the aim to obtain a better understanding of the compliant mechanism of Aldrovanda vesiculosa and its actuation. The latter is related to a change in turgor pressure in a so-called motor zone, adjacent to the midrib, possibly combined with prestressing effects. Apart from this scientific contribution to technical biology or reverse biomimetics, the abstraction of the trapping movement and its implementation in a façade element (Flectofold) as an example of biomimetic architectural design are briefly described.

Zusammenfassung

This paper presents results of the investigation of two biological role models, the shield bug (Graphosoma italicum) and the carnivorous Waterwheel plant (Aldrovanda vesiculosa). The aim was to identify biological construction and movement principles as inspiration for technical, deployable systems. The subsequent processes of abstraction and simulation of the movement and the design principles are summarized, followed by results on the mechanical investigations on various combinations of fibers and matrices with regard to taking advantage of the anisotropy of fiber-reinforced plastics (FRPs). With the results gained, it was possible to implement defined flexible bending zones in stiff composite components using one composite material, and thereby to mimic the biological role models. First small-scale demonstrators for adaptive façade shading systems – Flectofold and Flexagon – are proving the functionality.

Zusammenfassung

Recent developments in the field of segmented timber shells have shown promising structural and constructional characteristics. Advancements in computational design and digital fabrication enable architects and engineers to handle the increased geometric complexity necessary for this new construction type, integrating fabrication constraints and structural feedback in one design model. The research presented in this paper builds on new findings from biological role models for the constructional morphology, connection type, and material distribution of segmented shells. Based on the transfer of these principles, a robotic fabrication technique was developed that enables the production of elastically bent, double-layered segments made from custom-laminated beech plywood, by transferring traditional textile connection methods to timber construction. The construction system was evaluated through the design, production, and assembly of a large demonstrator.

Zusammenfassung

This paper presents the production and development of an adaptive robotically fabricated fiber composite compression shell with pneumatic formwork as a case study for investigating a generative behavioral design model and an adaptive, online mode of production. The project builds off of previous research at the University of Stuttgart on lightweight fiber composite structures which attempts to reduce the necessary formwork for fabrication while simultaneously incorporating structural, material and fabrication logics into an integrative computational design tool. This paper discusses the design development and fabrication workflow of the project, as well a set of strategies which were developed for online robotic programming in response to live sensor data.