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- Herausgeber: Wiley-VCH
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
Concrete is the most used building material. Its main component, cement, however, accounts production- related for up to 10 % of global CO2 emissions and is therefore a major contributor to human-induced climate change. Due to its low tensile strength, concrete must be further enhanced in tension with adequate reinforcement, such as steel. Producing the latter therefore additionally impacts the environment. Consequently, reducing the material amount for design and construction of structures, thus lowering material- and transport-induced emissions, represents a key element to climate protection. In this context, meeting the essential requirements ? sustainability, serviceability, durability ? is yet indispensable.
The book presents innovative optimization aided design methods for concrete structures. Mathematical optimization is applied to practical problems of structural concrete at each level: from external, through internal structure identification to cross-section design. It is shown how to design resource-efficient structures following the flux of forces, how to optimally adapt reinforcement layouts to the internal force flow, and how to efficiently cope with demanding cross-sectional design tasks such as biaxial bending.
The optimization aided design methods are discussed in detail and described vividly. They are independent of standards, concrete material (normal to ultra-high performance) and reinforcement type (steel fibers to carbon bars), thus universally applicable. The book illustrates the different approaches with numerous figures and calculation examples. Existing applications in structural engineering are presented to demonstrate the potential of optimization aided design concepts, including ultra-lightweight hybrid beams, thin concrete solar collectors, and improved reinforcement layouts for tunnel lining segments.
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Seitenzahl: 301
Veröffentlichungsjahr: 2022
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Table of Contents
Cover
Title Page
Copyright
Foreword by Manfred Curbachforeword
Intensifying Creativity in Construction
Notes
Foreword by Werner Sobekforeword
Building Emission‐Free for More People with Less Material
Note
Preface
List of Examples
Acronyms
About the Authors
Acknowledgments
1 Introduction
1.1 Preliminaries
1.2 Outer and Inner Shaping
1.3 Environmental Demands
1.4 Optimization Aided Design (OAD)
1.5 Structure of the Book
References
2 Fundamentals of Reinforced Concrete (RC) Design
2.1 Basic Principles
2.2 Verification Concept
2.3 Safety Concept
2.4 Materials
2.5 Load‐Bearing Behavior
References
3 Fundamentals of Structural Optimization
3.1 Structural Optimization Approaches
3.2 Problem Statement
3.3 Lagrange Function
3.4 Sensitivity Analysis
3.5 Solution Methods
References
4 Identification of Structures
4.1 One‐material Structures
4.2 One‐material Stress‐biased Structures
4.3 Bi‐material Structures
4.4 Examples
4.5 Applications
References
5 Internal Force Flow
5.1 Preliminaries
5.2 Continuum Topology Optimization (CTO) Approach
5.3 Truss Topology Optimization (TTO) Approach
5.4 Continuum‐Truss Topology Optimization (CTTO) Approach
5.5 Examples
5.6 Applications
References
Note
6 Design of Cross‐sections
6.1 Problem Statement
6.2 Equilibrium Iteration
6.3 Sectional Optimization
6.4 Solving
6.5 Parameterization
6.6 Examples
References
End User License Agreement
List of Tables
Chapter 1
Table 1.1 Specific strengths of construction materials: normal strength conc...
Chapter 4
Table 4.1 Material properties of Nanodur concrete according to [42] (
– mea...
Table 4.2 Collaborators of the project “ConSol.”
Table 4.3 Collaborators of the heliostat “transfer” project
Chapter 6
Table 6.1 Bending moment and required amounts of bottom and top reinforcemen...
Table 6.2 Reinforcement area
, flange height
, and minimized area
as func...
List of Illustrations
Chapter 1
Figure 1.1 Concrete shaped to the flow of forces: pylon of the Pont de Teren...
Figure 1.2 Railway concrete bridge with uniform single span girders and comp...
Figure 1.3 Reinforcement cages: (a) typical rectangular pattern of longitudi...
Figure 1.4 RC cross section designed under cost boundaries: (a) expensive fo...
Figure 1.5 Annual world consumption of water, cement, and aggregates, accord...
Figure 1.6 Development of the world population from
till
, according to [...
Figure 1.7 Traffic jam caused by a lane constriction to pass a construction ...
Figure 1.8 Age distribution of built bridges of a German city according to [...
Figure 1.9 Workers manually distributing and planning a concrete subbase.
Figure 1.10 Stepwise shaping of a single span girder with reduction in dead ...
Figure 1.11 OAD of a roof girder: (a) static system and design space, (b) op...
Figure 1.12 Optimization aided reinforcement design for a stepped beam place...
Chapter 2
Figure 2.1 (a) Load‐bearing principle of RC, (b) different types of reinforc...
Figure 2.2 Load‐bearing behavior of a bending beam in uncracked and cracked ...
Figure 2.3 Probability distributions of an action (
) and a resistance (
), ...
Figure 2.4 (a) Stress–strain diagram for concrete and (b) different material...
Figure 2.5 (a) Tensile force transmission across cracks and (b) various stee...
Figure 2.6 (a) Stress–strain relation of FRC under compression, (b) load‐bea...
Figure 2.7 (a, b) Compressive behavior of UHPC and constitutive models and (...
Figure 2.8 (a) Stress–strain curve for reinforcing steel and (b) consecutive...
Figure 2.9 Symmetric composite section under plane loadings, layered section...
Figure 2.10 Arbitrary composite section under spatial loadings, section of
Figure 2.11 Arbitrary RC section with
reinforcement points
, strain (
), ...
Figure 2.12 (a) Geometrical discontinuities, (b) statistical and/or geometri...
Figure 2.13 Exemplary D‐regions, associated principle stresses and correspon...
Chapter 3
Figure 3.1 Basic procedure of a structural optimization.
Figure 3.2 (a) Topology optimization, (b) shape optimization, and (c) sizing...
Figure 3.3 Organization of the approaches within this book.
Figure 3.4 (a) Simple optimization problem and (b) objective function, inequ...
Figure 3.5 Starting point dependence of the solutions using gradient descent...
Figure 3.6 Saddle point of a Lagrange function containing one inequality con...
Figure 3.7 Forward differentiation for a function dependent on one variable....
Chapter 4
Figure 4.1 Overview of Chapter 4: identification of structures.
Figure 4.2 Penalty exponent
in SIMP: (a) stiffness assignment, (b) impact ...
Figure 4.3 Numerical problems in topology optimization: (a) checkerboards, (...
Figure 4.4 Flow chart of the topology optimization approach.
Figure 4.5 Different optimization results depending on the load case definit...
Figure 4.6 Weighting factors with respect to the stress ratio and definition...
Figure 4.7 Unbiased, tension‐biased, and compression‐biased topology designs...
Figure 4.8 Flow chart of the stress‐biased topology optimization approach.
Figure 4.9 Stress–strain relationship for (a) compression‐only, (b) tension‐...
Figure 4.10 Bi‐material topology optimization: (a) checkerboards, (b) result...
Figure 4.11 Flow chart of the bi‐material topology optimization approach.
Figure 4.12 Influence of the employed material amount on the optimization re...
Figure 4.13 Influence of the sensitivity filter radius on one‐material topol...
Figure 4.14 Influence of the Young's modulus on one‐material topology optimi...
Figure 4.15 Pylon
example: (a) design space, (b) optimization result, (c) ...
Figure 4.16 Pylon
example: (a) design space, (b) optimization result, (c) ...
Figure 4.17 (a) Design space, (b) optimization result, (c) Daniel Hoan Memor...
Figure 4.18 (a) Design space, (b) optimization result, (c) Svinesund Bridge ...
Figure 4.19 Three‐span bridge example: (a) design space, (b) optimization re...
Figure 4.20 Wall with three point loads: (a) acting individually, (b) acting...
Figure 4.21 (a) Design space of a cantilever with vertical and horizontal lo...
Figure 4.22 Unbiased, tension‐affine and compression‐affine designs of a thr...
Figure 4.23 Bi‐material optimized structures for different ratios of the You...
Figure 4.24 Bi‐material optimized structures of a simple beam for material‐d...
Figure 4.25 Composite river bridge problem: (a) initial situation, (b) desig...
Figure 4.26 (a) Composite girder problem, (b) design space, (c) bi‐material ...
Figure 4.27 Composite arch bridge problem.
Figure 4.28 Principle of solar thermal collectors: (a) line‐focusing parabol...
Figure 4.29 Built‐up and installed “ConSol” concrete collector at the precas...
Figure 4.30 (a) Cross section of the shell with sickles and supports, (b) FE...
Figure 4.31 (a) Simplified loads and (b) topology optimization results for (...
Figure 4.32 (a) Optimization result for multiple load cases, (b) pattern of ...
Figure 4.33 Visualization of the parabolic shell with stiffeners and a detai...
Figure 4.34 Conceptual design of the strut‐like, modular heliostat made of H...
Figure 4.35 (a) Rotationally symmetric plate with hyperbolical thickness and...
Figure 4.36 (a) Segmental module with line‐like prestressing force
, (b) to...
Figure 4.37 Design studies for
,
and
: (a) Design space with loads and b...
Figure 4.38 Prototype of a modular concrete heliostat at the DLR solar tower...
Figure 4.39 (a) Reference RC beam, (b) design space and FE mesh, (c) bi‐mate...
Figure 4.40 (a) Reference beam, RC truss structure and hybrid truss structur...
Chapter 5
Figure 5.1 Overview of Chapter 5: strut‐and‐tie models, partly according to ...
Figure 5.2 Recommended procedure for the STMs striving CTO approach.
Figure 5.3 Examples for the components of a ground structure: geometric elem...
Figure 5.4 Different ground structures for a simple beam.
Figure 5.5 Transformation of a bar from local (
) to global (
) coordinates....
Figure 5.6 Dependence of the results on the ground structure (here:
).
Figure 5.7 (a) Approximation of the heaviside step function for different sh...
Figure 5.8 Controlling the complexity of optimization results by limiting th...
Figure 5.9 Flowchart of the TTO approach with complexity control.
Figure 5.10 Recommendations for modeling STMs optimization problems.
Figure 5.11 (a) Avoiding collinearity of overlapping bars at
, (b1) optimiz...
Figure 5.12 Recommended procedure for the STMs striving TTO approach.
Figure 5.13 Partial area loading: (a) classical STMs, (b) TTO, (c) CTO, (d) ...
Figure 5.14 CCTO: (a) superimposed design domains, (b) ground structures dep...
Figure 5.15 (a) Bilinear stress–strain relationship for concrete and steel, ...
Figure 5.16 Principle of truss layout simplification [17]: (a) initial resul...
Figure 5.17 Post‐processing the CTTO results: (a) stress limits in continuum...
Figure 5.18 Flow chart of the CTTO approach for solutions.
Figure 5.19 (a) Simple deep beam, (b) analysis model, (c) CTO results, (d) S...
Figure 5.20 (a) Continuous deep beam with openings problem, (b) CTO results,...
Figure 5.21 (a) Corbel problem, (b) analysis model, (c) CTO results, (d) CTO...
Figure 5.22 (a) Cantilever‐like beam problem, (b) analysis model, (c) CTO re...
Figure 5.23 (a) Shear load transfer problem, (b) CTO result, (c) STMs, adapt...
Figure 5.24 (a) Simple deep beam problem, (b) ground structures, (c) results...
Figure 5.25 Axial forces [kN] of different STMs for a deep beam: (a) STMs or...
Figure 5.26 (a) Frame corner with negative bending moment, (b) model and bas...
Figure 5.27 (a) Problem of a deep beam with a large block‐out and associated...
Figure 5.28 (a) Classical STMs for the deep beam with large opening problem ...
Figure 5.29 (a) Problem of a corbel, (b) analysis model and base mesh, (c) c...
Figure 5.30 (a) Core wall with two openings problem, adapted from [48], (b) ...
Figure 5.31 (a) Deep beam with small openings problem, (b) base mesh for
(...
Figure 5.32 (a) Short deep beam with large openings problem, (b) base mesh f...
Figure 5.33 (a) Continuous deep beam with openings problem, (b) base mesh, (...
Figure 5.34 Components of a tunnel with “cam & pot“ circumferential joints....
Figure 5.35 Optimization of the reinforcement layout at the pot of a circumf...
Figure 5.36 Test specimen representing the longitudinal joint of a tunnel li...
Chapter 6
Figure 6.1 Overview of Chapter 6: design of Cross‐sections.
Figure 6.2 Combination of sectional forces: uniaxial bending, uniaxial bendi...
Figure 6.3 Typical cross‐sections: RC, steel–concrete composites, FRC, layer...
Figure 6.4 Parameterized rectangular cross‐section under plane loadings
an...
Figure 6.5 Parameterized T‐section under spatial (left) or plane (right) loa...
Figure 6.6 Parameterized rectangular cross section under spatial loading wit...
Figure 6.7 Unsymmetric cross‐section with given loading
,
, reinforcements...
Figure 6.8 Spatial plane of strains (dashed lines) and distribution of the c...
Figure 6.9 Rectangular footing (
) under eccentric loading
with distributi...
Figure 6.10 Numerical results of block wise constant soil stresses in a spre...
Figure 6.11 T‐section with geometry parameters, reinforcements, and concrete...
Figure 6.12 Parameterized discretization of the T‐section and calculated con...
Figure 6.13 Rectangular cross‐section in axial bending with discretization....
Figure 6.14 I‐shaped RC section under bending, discretized into lamellae, wi...
Figure 6.15 Required flange areas of concrete under compression and rebars u...
Figure 6.16 Initial configuration of a rectangular footing under eccentric l...
Figure 6.17 (a) Optimized geometry of the footing, (b) distribution of soil ...
Figure 6.18 Related developments of the optimization variables
,
,
and t...
Guide
Cover Page
Title Page
Copyright
Foreword by Manfred Curbach
Foreword by Werner Sobek
Preface
List of Examples
Acronyms
About the Authors
Acknowledgments
Table of Contents
Begin Reading
WILEY END USER LICENSE AGREEMENT
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Optimization Aided Design
Reinforced Concrete
Georgios Gaganelis, Peter Mark, and Patrick Forman
Authors
Dr.‐Ing. Georgios Gaganelis
Univ.-Prof. Dr.‐Ing. habil. Peter Mark
Dr.‐Ing. Patrick Forman
Institute of Concrete Structures
Faculty of Civil and Environmental Engineering
Ruhr University Bochum
Universitätsstraße 150
44780 Bochum
Germany
Coverfoto: Talbrücke Lindenau A44
Copyright: Aljona Riefert, KINKEL + PARTNER, Dreieich, Germany
Photo editing: Patrick Forman, Razan Karadaghi
Executing companies:
KINKEL + PARTNER, Dreieich, Germany (structural design)
Züblin Hoch‐ und Brückenbau GmbH, Bad Hersfeld, Germany (construction)
Unless otherwise stated, the rights to the
figures are held by the authors.
All books published by Ernst & Sohn are carefully produced. Nevertheless, authors, editors, and publisher do not warrant the information contained in these books, including this book, to be free of errors. Readers are advised to keep in mind that statements, data, illustrations, procedural details or other items may inadvertently be inaccurate.
Library of Congress Card No.: applied for
British Library Cataloguing‐in‐Publication Data
A catalogue record for this book is available from the British Library.
Bibliographic information published by the Deutsche Nationalbibliothek
The Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available on the Internet at <http://dnb.d-nb.de>.
© 2022 Wilhelm Ernst & Sohn, Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Rotherstraße 21, 10245 Berlin, Germany
All rights reserved (including those of translation into other languages). No part of this book may be reproduced in any form – by photoprinting, microfilm, or any other means – nor transmitted or translated into a machine language without written permission from the publishers. Registered names, trademarks, etc. used in this book, even when not specifically marked as such, are not to be considered unprotected by law.
Print ISBN: 978‐3‐433‐03337‐1
ePDF ISBN: 978‐3‐433‐61071‐8
ePub ISBN: 978‐3‐433‐61070‐1
oBook ISBN: 978‐3‐433‐61072‐5
Foreword by Manfred Curbach
Intensifying Creativity in Construction
There is hardly a topic among building professionals that is discussed more intensively than sustainable construction. In view of the emphasis on this topic, it appears that intensive work is being done on the implementation of this challenge, both in research and in realization. After all, it is about nothing less than building in a way that enables all people of the generations to come to live a decent life on this earth. Because we have only this one. In 1994, the astronomer and astrophysicist Carl Sagan had the idea of taking a photo of the Earth with the help of the Voyager 1 space probe after it left the solar system. In a lecture on 13 October 1994 at the Cornell University, he said the following about this:
Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves. There is perhaps no better demonstration of the folly human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we've ever known.1
In fact, we are overexploiting and consuming the resources of our earth and changing them massively. The consequences are climate change, scarcity of resources, natural disasters, hunger, flight, and misery. And the construction industry is massively involved in these developments.
The building industry in Germany accounted for 5.3% of nominal gross value added in 2018 (€179.6 billion GDP of €3388.2 billion GDP)2 but causes around 25% of CO2 emissions and uses around 40% of the energy generated.3
This discrepancy alone should lead to enormous productive activities. But what is the reality in terms of efficiency and research?
In sectors such as manufacturing (excluding construction), productivity increased by around 70% from 1995 to 2016, whereas in construction it only increased by around 5%.4
In terms of industry investment in research and development, out of a total of 436 571 people (in full‐time equivalents) in 2017, only 1147 people came from the construction industry, i.e. 0.26%.5
The Federal Government of the Federal Republic of Germany spent a total of €17 250 million on research and development in 2018. Of this, €118.1 million was allocated to the area of “Regional planning and urban development; construction research,” i.e. 0.69%.6
Considering only the Federal Ministry of Education and Research, a total of €10 486.7 million was invested in 2018. The area of “Regional planning and urban development; construction research” accounted for a share of only €27.5 million, i.e. 0.26%.
In 2019, the annual grant total from the German Research Foundation amounted to around €3285.3 million. The field of Civil Engineering and Architecture received grants totaling €51.5 million, i.e. 1.57%.7
The result of this small survey illustrates that in one of the most important industries in Germany, which contributes disproportionately to climate change, efficiency is stagnating and, at the same time, research is receiving severely below‐average funding.
Every 12 years, the population of the earth grows by 1 billion people8 who need a decent home, infrastructure, and energy supply. In view of the continuing increase in the world's population, we will not build less, but more. Contrary to this, we need to radically limit resource consumption and CO2 emissions. It is obvious that in the future, building will have to be completely different, not just marginally, but fundamentally.
It is thus clear that we must significantly intensify research in the construction industry. Because of its enormous leverage effect, this is therefore one of the most important tasks for the future, both nationally and internationally, with extremely great significance for society as a whole. At all levels, from basic research to realization, for all available and newly to be developed building materials and combinations of building materials, in all areas of our social life up to politics, we have to become much more creative. Only through our inventiveness, our power of imagination for realization, our abilities to mentally penetrate complex processes will we change the entire building
