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Computation of Principal Stress-Aligned Rebar Layouts
Abstract
Despite innovations in computational design and digital fabrication , little attention has been paid so far to investigate the structural implications of novel reinforcement distributions in concrete building components. In this context, a computational framework for the generation and structural validation of rebar layouts is presented. Featuring custom reinforced concrete design and non-linear finite analysis modules, the framework retakes the concept of principal stresses and proposes a distance-constrained algorithm that generatively traces stress-aligned reinforcement bars.
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Whereas entire houses are reported to be built by means of 3D Concrete Printing (3DCP), automated integration of reinforcement is still a vastly unresolved challenge and - undoubtfully - a crucial requirement for widespread adoption of 3DCP in construction practice. The disruptive technology of 3DCP opens up the chance to overcome insufficiencies of conventional steel reinforcement and its rationalised orthogonal use. This paper discloses a field of options for future construction by exploring possible reinforcement strategies for different kinds of cement-based Additive Manufacturing techniques using continuous textile fibres. A methodology is introduced to identify, compare and assess new processes for integration of fibre reinforcement based on robotic winding. Two novel approaches will be described regarding Large Particle 3D Concrete Printing and Shotcrete 3d Printing. Respective case studies will be presented in order to give a basic proof of concept.
The paper describes the physical realisation of a 3D-concrete-printed, mortar-free, unreinforced masonry arched footbridge, designed for disassembly and reuse. The paper also details the novel integrated design, engineering and fabrication framework and the manufacturing and assembly processes used for the project. The research, motivated by the rapid growth in large-scale 3D concrete printing (3DCP), addresses the current lack of both design tools and integrated design-to-production solutions. It is guided by the insight regarding the applicability of design and analysis methods used in unreinforced masonry to large-scale, layered 3D printing with compression dominant materials such as concrete. Thus, the underlying computational framework and integrated design environment further extends and adapts advances in the computational design and analysis of unreinforced masonry structures to 3DCP masonry blocks. Adopting an unreinforced masonry paradigm for the design of 3DCP structures can make it possible to (i) reduce the amount of concrete used by allowing precise placement of concrete only where needed along the compressive flow of forces, (ii) reduce the amount of steel needed by reducing tensile and flexural strength requirements through a compression-appropriate design of both the global, shape and the block discretisation, and (iii) reuse components, repair the structures and recycle materials more easily. This paper builds on the relevance of the computational masonry paradigm to both delivering the ecological promises of 3DCP and to the development of a 3DCP-specific, design-to-production toolkit.
Concrete is a major contributor to the environmental impact of the construction industry, due to its cement content but also its reinforcement. Reinforcement has a significant contribution because of construction rationalisation, resorting to regular mats or cages of steel bars, despite layout-optimisation algorithms and additive-manufacturing technologies. This paper presents an automated framework, connecting design and fabrication requirements for the op-timisation of spatial layouts as of reinforcement of concrete structures, by the means of robotic filament winding.
We present a computational technique that aids with the design of structurally‐sound metal frames, tailored for robotic fabrication using an existing process that integrate automated bar bending, welding, and cutting. Aligning frames with structurally‐favorable orientations, and decomposing models into fabricable units, we make the fabrication process scale‐invariant, and frames globally align in an aesthetically‐pleasing and structurally‐informed manner. Relying on standard analysis of frames, we then co‐optimize the shape and topology of bars at the local unit level. At this level, we minimize combinations of functional and aesthetic objectives under strict fabrication constraints that model the assembly of discrete sets of bent bars. We demonstrate the capabilities of our global‐to‐local approach on four robotically‐constructed examples.
Global production of cement has grown very rapidly in recent years, and, after fossil fuels and land-use change, it is the third-largest source of anthropogenic emissions of carbon dioxide. The availability of the required data for estimating emissions from global cement production is poor, and it has been recognised that some global estimates are significantly inflated. This article assembles a large variety of available datasets, prioritising official data and emission factors, including estimates submitted to the UN Framework Convention on Climate Change (UNFCCC), plus new estimates for China and India, to present a new analysis of global process emissions from cement production. Global process emissions in 2018 were 1.50±0.12 Gt CO2, equivalent to about 4 % of emissions from fossil fuels. Cumulative emissions from 1928 to 2018 were 38.3±2.4 Gt CO2, 71 % of which have occurred since 1990. The data associated with this article can be found at 10.5281/zenodo.831454 (Andrew, 2019).
This paper describes how 3D-printed formwork can be used to facilitate the integration of functional features in structurally optimised concrete slabs. The weight of concrete slabs represents the largest portion of the weight of a concrete framed, multi-storey building. Despite this significant share, slabs are usually designed as monolithic, oversized boxes due to various construction constraints. Optimised design alternatives, featuring funicular shapes, differentiated ribs, profiled soffits and hollow sections use significantly less material and can moreover integrate building services within the thickness of the slab, such as heating, cooling and ventilation. Nevertheless, both the optimised external geometry and the internal network of functional voids present very complex fabrication challenges for concrete. This is because standard commercial formwork systems are not suitable for bespoke designs. To address this limitation, this research demonstrates how fused-deposition 3D printing can be used for the fabrication of custom formwork for a functionally integrated concrete slab. The resulting prototype efficiently uses material and integrates provisions for an active beam ventilation system within the standard structural depth of the slab. All these intricate geometric features are achieved with an ultra-lightweight 3D-printed formwork, which weighs less than 15 kg for the 660 kg concrete slab.
Designing freeform architectural surfaces with due regard to economic and feasibility factors is a challenging task. Rationalizing such surfaces by means of quadrilateral meshes following principal curvature lines has proven to be beneficial for manufacturing reasons, such as planar cladding panels and simplified substructure connections. On the other hand, for structural efficiency, it is convenient to ensure static equilibrium in the load bearing structure through axial forces only. It turns out that both of these goals can be reached for surfaces in membrane equilibrium where principal stress and curvature directions coincide. In this paper, we present a method for the optimization of a given shape towards stress and curvature alignment, within a workflow for the design of principal meshes in equilibrium. Our method can be applied to shapes without any geometric or topological limitation.
Topology optimization can be used as a design method to reduce material without affecting the functionality of an object.
Despite being one of the most demanding economic sectors in terms of material consumption, the construction industry
has not yet adopted such design methods. This is generally because computational optimization algorithms produce
solutions which are difficult to fabricate, especially at a large scale. This research investigates the feasibility of using
additive manufacturing to produce large‐scale building components with optimized material distribution. To evaluate this
new approach, two large horizontal load‐bearing slab prototypes were designed using different topology optimization
algorithms and fabricated with a hybrid 3D printing and casting method.
Digital fabrication with concrete has become a highly interesting topic due to the potential for freeform architecture and efficient material placement, with major strides in its development taking place in the past few years. However, reinforcement remains problematic, as current technologies rely mostly on post-hoc placement and infill. In this paper, we present the Mesh Mould, a digital fabrication technology unifying formwork and reinforcement, wherein a mobile robotic arm with a specially designed end effector bends, welds, and cuts steel reinforcement to additively manufacture a digitally designed mesh either onsite or in a prefabricated environment. This mesh is subsequently infilled with concrete and finished with a cover layer to serve as a freeform reinforced concrete structural element. Research challenges for various fields such as robotics, concrete technology, structural engineering, as well as architecture are presented, highlighting the multidisciplinarity of the project and serving as a microcosm of how synergies between disparate fields can be exploited within this burgeoning area of research.
From Egypt and Classical Greece and Rome through the building booms of the Gothic era and the Renaissance, and from the Industrial Revolution to the present era of digital modelling, Building: 3,000 Years of Design, Engineering, and Construction, charts centuries of innovations in engineering and building construction. This comprehensive and heavily illustrated volume, aimed at students and young professionals as well as general readers, explores the materials, classic texts, instruments, and theories that have propelled modern engineering, and the famous and not-so-famous buildings designed through the ages, from the Parthenon to Chartes Cathedral and the dome of St. Peter's, from eighteenth-century silk mills in England to the Crystal Palace, and on to the first Chicago high-rises, the Sydney Opera House, and the latest "green" skyscrapers.
The book concentrates on developments since the industrial and scientific revolutions of the seventeenth and eighteenth centuries. Incorporated within the continuous narrative are sidebars with short biographies of eminent engineers, excerpts from classic texts, stories of individual projects of major importance, and brief histories of key concepts such as calculus. Also included are extensive reference materials: appendices, a glossary, bibliography, and index.
This book is out of print but now available on line:
https://archive.org/details/building3000year0000addi
Ultra-high performance fibre reinforced concrete (UHPFRC) is a relatively new construction material. In comparison with conventional high strength concrete UHPFRC usually does not contain coarse aggregates larger than 6–7 mm in size. This paper presents the outcomes of an experimental study of UHPFRC beams subjected to four-point loading. The effect of two parameters was studied, namely the fibre content and the temperature of curing water. Eight UHPFRC beams comprising 6 beams reinforced with rebars and two beams without rebars were tested. Three fibre contents were investigated in this study (1%, 2% and 4% in volume). The study investigated two curing temperatures of water which are 20°C and 90°C. The results presented in this paper include deflections, toughness energy and moment capacity and also includes a comparison with calculations according to EC2 provisions. A minor difference was observed in the deformation and flexural behaviour of beams with fibre contents of 1% and 2% (in volume). However, beams with 4% (in volume) fibres exhibited a higher flexural capacity. Only flexural failure was observed and no shear related failure was recorded. Beams with 1% (in volume) fibres for both curing regimes had the highest peak-load toughness energy. Beams reinforced with rebars and cured at 20°C had a significantly higher bending resistance.
This paper presents an historical and analytical evaluation of the ribbed floor slab systems developed by the Italian structural artist Pier Luigi Nervi (1891-1979). The historical discussion includes the evolution of the floor slab from a non-structural element to an inspired structural system, culminating in Nervi's patented ribbed floor systems. While the isostatic inspiration for the rib patterns of Nervi's floor systems is well-documented, the method used to generate these patterns is considerably unknown by comparison. The methods of experimental stress analysis identified by Nervi and the mathematical theories available prior to the 1949 isostatic floor system patent are discussed to clarify the means used to generate the isostatics. An Isostatic Line Tool developed for this paper is used to evaluate the correlation between the isostatics and Nervi's arrangement of ribs for the Gatti Wool Factory, Palace of Labor, and Large Sports Palace floor systems. This tool can be used by designers in the conceptual design phase to develop ribbed floor systems inspired by Nervi.
Construction material consumption is greater than any time in history. Australia produces approximately 30 million tonnes of finished building products each year, with over 56% of this quantity, by mass, being attributed to concrete and a further 6%, steel. Globally, 23 trillion kilograms of concrete alone is consumed annually, with growing population driving increasing demands. This study assesses the environmental performance of various concrete slab systems. Historically, the focus of environmental performance in buildings has been Operation Energy (OE) requirements, however Zero Energy Buildings (ZEB) are changing this. Specifically the study investigates the environmental performance of concrete structures varying design parameters and construction techniques to optimise its embodied energy (EE). These structures are designed in accordance with all relevant Australian codes and standards. The various slab systems investigated include: beam & slab, flat slab and flat plates while concurrently considering the use of conventionally reinforced and post-tensioned construction methods. Designs were compared in terms of EE outcomes given fixed design criteria, with results indicating reductions between 23.7% and 49.1% when utilising post-tensioned construction methods.
If robots are to be employed in the construction of high-rise structures, logistics and material systems have to be entirely rethought to cater for both their abilities and limitations: robots have limited loading capacity, but greater dexterity than other on-site, automated construction techniques. Here, Norman Hack of ETH Zurich and Willi Viktor Lauer of the Future Cities Laboratory (FCL) at the Singapore-ETH Centre for Global Environmental Sustainability (SEC) describe the research they have undertaken to develop ‘mesh-mould’ as an alternative to conventional formwork.
Over the course of the 20th century, architectural construction has gone through intense innovation in its material, engineering and design, radically transforming the way buildings were and are conceived. Technological and industrial advances enabled and challenged architects, engineers and constructors to build increasingly complex architectural structures from concrete. Computer-aided design and manufacturing (CAD/CAM) techniques have, more recently, rejuvenated and increased the possibilities of realising ever more complex geometries. Reinforced concrete is often chosen for such structures as almost any shape can be achieved when placed into a formwork. However, most complex forms generated with these digital design tools bear little relation to the default modes of production used in concrete construction today. A large gap has emerged between the possibilities offered by digital technology in architectural design and the reality of the building industry, where actually no efficient solutions exist for the production of complex concrete structures. This paper presents construction methods that unfold their full potential by linking digital design, additive fabrication and material properties and hence allow accommodating the construction of complex concrete structures. The emphasis is set on the on-going research project Smart Dynamic Casting (SDC) where advanced material design and robotic fabrication are interconnected in the design and fabrication process of complex concrete structures. The proposed fabrication process is belonging to an emerging architectural phenomena defined first as Digital Materiality by Gramazio & Kohler (2008) or more recently as Material Ecologies by Neri Oxman [2].
A unified design concept, which is consistent for all types of structures and all their parts, is required. To be satisfactory, this concept must be based on realistic physical models. Strut-and-tie models, a generalizatian of the well known truss analogy method for beams, are proposed as the appropriate approach for designing structural concrete, which includes both reinforced and prestressed concrete structures. This report shows how suitable models are developed and proposed criteria according to which the model's elements can be dimensioned uniformly for all possible cases. The concept is explained using numerous design examples, many of which treat the effect of prestress.
. This paper presents a new evenly-spaced streamlines placement algorithm to visualize 2D steady flows. The main technical contribution of this work is to propose a single method to compute a wide variety of flow field images, ranging from texture-like to hand-drawing styles. Indeed the control of the density of the field is very easy since the user only needs to set the separating distance between adjacent streamlines, which is related to the overall density of the image. We show that our method produces images of a quality at least as good as other methods but that it is computationally less expensive and offers a better control on the rendering process. Introduction The problem of visualizing vector fields has been widely addressed in the past years because it has numerous applications. The main issue is to visualize properly the direction and magnitude of the flow. Spatial resolution techniques such as arrow plots, streamlines or particles traces suffer from their spatia...
Currently, additive manufacturing in concrete construction can be divided into three main methods: firstly, material extrusion, secondly material spraying, and thirdly particle bed binding, with the material typically being applied in layers. In contrast, Injection 3D Concrete Printing (I3DCP) is based on the concept that a fluid material A is deposited spatially free into a material B with specific rheological properties, keeping material A in a stable position within material B. Thus, in contrast to the layered deposition of horizontal strands, free-form three-dimensional concrete structures can be printed entirely in one piece.
In general, three versions of Injection 3D Concrete Printing can be classified: a) injecting a fine-grained concrete into a non-hardening carrier liquid; b) injecting a non-hardening suspension into a fine-grained concrete; c) injecting fine-grained concrete with specific properties into concrete with different properties. This paper focuses on Injection 3D Concrete Printing into a carrier liquid.
For a deeper understanding of the underlying physical mechanisms, we carry out experiments that vary the rheological properties of the carrier liquid, the concrete flow rate, and the nozzle displacement velocity. We use a ground limestone suspension as carrier liquids in this study. We investigate the effect of the rheological properties of the carrier liquid on the positional stability of the injected concrete in small-scale print experiments. Based on this, we develop an analytical model that describes the positional stability as a function of the rheological properties. Also, we highlight that the final cross-section of the injected concrete strand is dependent on the concrete flow rate and nozzle velocity. Finally, we present the first reinforced I3DCP-elements and current developments of this novel technology for lightweight space frame structures in concrete construction.
Digital fabrication techniques with concrete and cementitious materials have seen a large amount of research and industrial activity recently, with industrialization of techniques such as 3D printing becoming more of a reality. The potential to revolutionize construction is real, not only through reducing costs, but also bringing more sustainability and increased functionality. Material challenges are significant, chief among them understanding and controlling early age hydration and the link to rheology, incorporation of reinforcement, and overall, the link between processing, material, and performance, both from a structural and durability point of view. Interdisciplinarity is crucial, as the field brings together many disparate fields and has been driven by fields such as architecture so far. This article is a review of the state of the art in the newly forming field of digital fabrication with concrete, and aims to provide some direction in terms of the research challenges encountered thus far.
The fabrication of novel reinforced concrete structures using digital technologies necessarily requires the definition of suitable strategies for reinforcement implementation. The successful integration of existing reinforcement systems, such as steel rebar, rods, wires, fibres or filaments, will indeed allow for printed concrete structures to be designed using standard structural codes. However, reinforcement integration has to be compatible with either the specific printing technique adopted for the structural element production or with its shape. This paper provides a systematic overview of a number of digital fabrication techniques using reinforced concrete that have been developed so far, proposing a possible organization by structural principle, or place in the manufacturing process.
Contemporary innovations in structural form-finding and fabrication techniques are leading to design of freeform masonry architecture. These new forms create new challenges in laying out tessellation patterns, especially if structural, fabrication and construction requirements as well as aesthetical considerations are taken into account. Addressing these challenges, we review historic stone-cutting strategies and their geometric principles, forming the base for the development of two new discretisation approaches for given thrust surfaces, allowing for various degrees of user control. First, we introduce a tessellation approach based on primal, anisotropic triangular meshes and their dual counterparts. Second, an alternative tessellation approach based on transverse cutting curves is presented. Using a simple set of geometric rules, both methods enable the design of rigid, staggered bonds with locally force-flow aligned block configurations to avoid sliding failures. For this research, the tessellation design of the Armadillo Vault, an unreinforced, dry-assembled, cut-stone stone shell, served as a case study to demonstrate the feasibility of our methods in the context of a full-scale architectural project.
A novel formwork system is presented as a material saving, labour reducing and cost-effective solution for the casting of bespoke doubly curved concrete geometries. The approach uses a custom knit technical textile as a lightweight stay-in-place formwork with integrated solutions for the insertion of additional elements, and is fabricated as a nearly seamless fabric. Using weft knitting as the textile formation technique minimises the need for cutting patterns, sewing, welding or gluing, when compared to conventional weaving and gives the possibility to integrate channels, openings, have varying widths and directional material properties, thus broadening the geometric design space. The system has been tested through a small-scale concrete footbridge prototype, built using a pre-stressed hybrid knitted textile and a bending-active structure that acted as a waste-free, stay-in-place, self-supporting formwork. Through the gradual buildup of strength in thin layers of concrete, formwork deformations during casting were minimised. This allowed for low tensioning of the fabric and the possibility to use more pressure (e.g. during shotcreting) in applying the subsequent concrete without intermediate support from below. The computational design and fabrication of the knitted textile formwork included integrated channels for the insertion of bending-active rods, tensioning ribbons and features for controlling the concrete casting. The analysis and process of increasing the stiffness of the lightweight and flexible formwork is presented. The hybrid approach results in an ultra-lightweight formwork that is easily transportable and significantly reduces the need for falsework support and scaffolding, which has many advantages on the construction site.
Discrete steel fibers are known to control crack widening in concrete members thereby enabling them to carry loads up to large deflections. This study examined the flexural behavior of steel fiber reinforced concrete (SFRC) beams reinforced with steel fibers by conducting four-point bending tests on eight beam specimens. The effect of reinforcing index (defined as the product of the volume fraction and the aspect ratio of steel fibers), fiber type, and beam depth was investigated. The load-carrying capacity corresponding to different beam deflections was predicted using available constitutive stress–strain/crack width laws in tension. Although existing constitutive relations in tension predict the peak load capacity well, they fail to accurately predict the load-carrying capacity at large deflections. Subsequently, a constitutive law is proposed using a back-calculation technique which was validated with the results from four-point bending tests conducted on 24 SFRC beams including 16 results found in the literature. The deviation of the predictions of the proposed model with regard to the average load-carrying capacity at large deflections is within 12% from the observed values.
Optimization techniques developed for additive manufacturing (AM) to maximize the structural stiffness of printed parts are often computationally expensive reformulations of classical procedures that do not typically consider the mechanical behavior introduced to the printed part by the AM fabrication process, which is layer-based, and result in pieces with significant anisotropy. The misalignment of filament orientation and structural action negates the potential benefits of optimization. Addressing this problem, this article presents a two-part research approach exploring a new method of material deposition called Stress Line Additive Manufacturing (SLAM), which deposits filament along paths derived from principal stress lines. The proposed method unifies the design and optimization of the geometry and filament layout of AM-produced parts, and is compatible to the operational characteristics of fused deposition modeling (FDM). Experimentally validating the structural significance of oriented filament, the first part of the research implements SLAM on a commercial platform for planar design cases. Ongoing research to adapt SLAM for complex 2.5D surface geometries using a six-axis industrial robot arm and a custom-designed heated extruder is then presented in Implementation 2: Robot-Enabled SLAM for 2.5-D Cases. The presented research opens new possibilities for structurally performative fabrication.
Principal stress-lines are pairs of orthogonal curves that indicate trajectories of internal forces. Subsequently, these curves idealize paths of material continuity, and naturally encode the optimal topology for any structure for a given set of boundary conditions. Stress-line analysis has the potential to offer a direct and geometrically-provocative approach to optimization that can synthesize both design and structural objectives. However, its application in design has generally been limited due to a lack of standardization and parameterization of the process for generating and interpreting stress lines. Addressing these barriers, this thesis proposes a new implementation framework that enables designers to take advantage of stress-line analysis to inform conceptual structural design. Central to the premise of this research is a new conception of structurally-inspired design exploration that does not impose a singular solution, but instead allows for the exploration of a diverse high-performance design space in order to balance the combination of structural and architectural design objectives. Specifically, the thesis has immediate application for the topological design of both regular and irregular thin shell structures predominately subjected to in-plane and compressive structural actions.
An increasing number of architectural design practices harness the power of parametric design tools. The aim of these tools is to facilitate and control complex building geometries. Parametric design programs such as Grasshopper (GH) for Rhino or Generative Components popularized this approach by providing easy-to-use visual programming environments that integrate with computer-aided design (CAD) packages. A logical next step consists in connecting parametric designs to applications that evaluate non-geometric aspects such as building physics or structural performance. This brings about new opportunities of collaboration between architects and engineers in the early stages of building design. The ease of testing alternatives by tweaking a set of parameters also opens the door for the application of generic optimization algorithms. Karamba is a finite element program geared towards interactive use in the parametric design environment GH. Being a GH plug-in, it seamlessly integrates with the diverse habitat of other third party programs available for GH. These range from building physics applications to genetic optimization engines. In the author's company, Karamba is used in early-stage design, form-finding, and structural optimization. “White Noise”, a mobile exhibition pavilion for the Salzburg Biennale, serves as a case study that shows how Karamba can be used to optimize the structural performance of intricate building geometries.
The word plate is a collective term for systems in which transfer of forces occurs in two directions; walls, deep beams, floors and bridge slabs are all plates. We distinguish two main categories, plates that are loaded in their plane, and plates loaded perpendicularly to their plane. For both categories we give an approach with differential equations, such that a basic understanding is provided and for certain characteristic cases an exact solution can be determined. We follow the displacement method, working with differential equations. In plates that are loaded in their plane, the plane stress state is called the membrane state. All stress components are parallel to the mid- plane of the plate. In special cases we can simply determine the stresses.
The problem of designing reinforced concrete plates and shells has interested researchers for a long time. The recent development of the computers' performance and storage capacity combined with powerful numerical methods revealed the need of a clear procedure to design elements subjected to membrane and flexure forces. In the present study this problem is formulated based on the equilibrium conditions and an iterative procedure is suggested. The computational code based on this approach is given, as well as some examples of the method.
The use of finite-element packages by practioners as a design tool for reinforced concrete structures has increased considerably in the last few decades. All structural codes of practice recognize the assumption of linear elastic behavior at a design stage. However, the problem remains of calculating the required reinforcement in plates and shells. The amount of reinforcement is determined locally, i.e., for each sampling point, from the equilibrium between applied and internal forces. The formulation of the method includes biaxial behavior of concrete and different lever arms for all the internal forces. Ideal plastic behavior is assumed for both materials. A reference is made to the absence of universally accepted solutions for the design of these structures and, therefore, scarcity of provisions in the structural concrete codes. To appraise the validity of the method, a comparison is made with experimental tests on slab and shell elements. Additional numerical results for practical structures are also given.
Although the use of Fibre Reinforced Concrete (FRC) for structural applications is continuously increasing, it is still limited
with respect to its potentials, mainly due to the lack of International Building Codes for FRC structural elements. Within
fib (Féderation Internationale du Béton), the Special Activity Group 5 is preparing a New fib Model Code that aims to update
the previous CEB-FIP Model Code 90, published in 1993, that can be considered as the reference document for Eurocode 2. The
New Model Code includes several innovations and addresses among other topics, new materials for structural design. In this
respect, FRC will be introduced. The Technical Groups fib TG 8.3 “Fibre reinforced concrete” and fib TG 8.6 “Ultra high performance FRC” are preparing some sections of the New Model Code, including regular and high performance
FRC. This paper aims to briefly explain the main concepts behind the structural rules for FRC structural design.
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Architecture, 2009. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. Includes bibliographical references (p. 145-153). This dissertation presents Thrust Network Analysis, a new methodology for generating compression-only vaulted surfaces and networks. The method finds possible funicular solutions under gravitational loading within a defined envelope. Using projective geometry, duality theory and linear optimization, it provides a graphical and intuitive method, adopting the same advantages of techniques such as graphic statics, but offering a viable extension to fully three-dimensional problems. The proposed method is applicable for the analysis of vaulted historical structures, specifically in unreinforced masonry, as well as the design of new vaulted structures. This dissertation introduces the method and shows examples of applications in both fields. Thrust Network Analysis, masonry, historic structures, compression-only structures, limit analysis, equilibrium analysis, funicular design, form-finding, structural optimization, Gothic vaults, reciprocal diagrams. by Philippe Block. Ph.D.
Metallurgical iron cycles are characterized for four anthropogenic life stages: production, fabrication and manufacturing, use, and waste management and recycling. This analysis is conducted for year 2000 and at three spatial levels: 68 countries and territories, nine world regions, and the planet. Findings include the following: (1) contemporary iron cycles are basically open and substantially dependent on environmental sources and sinks; (2) Asia leads the world regions in iron production and use; Oceania, Latin America and the Caribbean, Africa, and the Commonwealth of Independent States present a highly production-biased iron cycle; (3) purchased scrap contributes a quarter of the global iron and steel production; (4) iron exiting use is three times less than that entering use; (5) about 45% of global iron entering use is devoted to construction, 24% is devoted to transport equipment, and 20% goes to industrial machinery; (6) with respect to international trade of iron ore, iron and steel products, and scrap, 54 out of the 68 countries are net iron importers, while only 14 are net exporters; (7) global iron discharges in tailings, slag, and landfill approximate one-third of the iron mined. Overall, these results provide a foundation for studies of iron-related resource policy, industrial development, and waste and environmental management.
THIN SHELL CONCRETE STRUCTURES : THE MASTER BUILDERS
- David P Billington
- Maria M Garlock
Billington, David P, and Maria M Garlock. 2004. "THIN SHELL CONCRETE
STRUCTURES : THE MASTER BUILDERS." In Symposium IASS.
Pier Luigi Nervi: Architecture as Challenge
- Mario A Chiorino
- Cristiana Chiorino
Chiorino, Mario A., and Cristiana Chiorino. 2011. "Pier Luigi Nervi: Architecture as Challenge." International Journal of Structural Engineers World
Congress.
Nervi's Isostatically Inspired Ribbed Floors: From the Ribbed Floor Slab Systems of Pier Luigi Nervi
- Allison B Halpern
- P David
- Sigrid Billington
- Adriaenssens
Halpern, Allison B., David P. Billington, and Sigrid Adriaenssens. 2017. "Nervi's Isostatically Inspired Ribbed Floors: From the Ribbed Floor Slab Systems
of Pier Luigi Nervi." In Model Perspectives: Structure, Architecture and Culture. https://doi.org/10.4324/9781315091105.
Practitioner's Guide to Finite Element Modelling of Reinforced Concrete Structures
- Elzbieta Horszczaruk
- Piotr Brzozowski
Horszczaruk, Elzbieta, and Piotr Brzozowski. 2017. "Properties of Underwater Concretes Containing Large Amount of Fly Ashes." In Procedia Engineering, 196:97-104. Elsevier. https://doi.org/10.1016/j.proeng.2017.07.178.
International Federation for Structural Concrete. 2008. "Practitioner's Guide
to Finite Element Modelling of Reinforced Concrete Structures." Lausanne:
International Federation for Structural Concrete.
COMPAS: A Framework for Computational Research in Architecture and Structures
- Tom Mele
- Andrew Van
- Liew
Mele, Tom Van, Andrew Liew, Tomás Méndez Echenagucia, and Matthias Rippmann. 2017. "COMPAS: A Framework for Computational Research in Architecture and Structures." http://compas-dev.github.io/compas/.
Eigenshells: Structural Patterns on Modal Forms
- Panagiotis Michalatos
- Sawako Kaijima
Michalatos, Panagiotis, and Sawako Kaijima. 2014. "Eigenshells:
Structural Patterns on Modal Forms." In Shell Structures for
Architecture: Form Finding and Optimization, 1st ed. London:
Routledge. https://doi.org/10.4324/9781315849270.
Structural Design of Free-Curved RC Shells: An Overview of Built Works
- Mutsuro Sasaki
Sasaki, Mutsuro. 2014. "Structural Design of Free-Curved RC Shells: An
Overview of Built Works." In Shell Structures for Architecture: Form Finding
and Optimization. https://doi.org/10.4324/9781315849270.
Freiburger Knochendecke Ist Vorbild Für Optimale Leichtbaukonstruktion
- Detlef Stoller
Stoller, Detlef. 2014. "Freiburger Knochendecke Ist Vorbild Für Optimale
Leichtbaukonstruktion." Ingenieur.De. 2014. https://www.ingenieur.de/technik/fachbereiche/architektur/freiburger-knochendecke-vorbild-fuer-optimale-leichtbaukonstruktion/.
Eurocode 2: Design of Concrete Structures -Part 1-1: General Rules and Rules for Buildings
- Cen
CEN. 2004. "EN 1992-1-1:2004. Eurocode 2: Design of Concrete Structures -Part 1-1: General Rules and Rules for Buildings."
Eurocode 2. Design of Concrete Structures -Part 2: Concrete Bridges-Design and Detailing Rules
European Committee for Standardization (ECS). 2005. "Eurocode 2.
Design of Concrete Structures -Part 2: Concrete Bridges-Design
and Detailing Rules." European Standard. Brussels: BSI British
Standards. https://doi.org/10.3403/30096437.