Structures that behaves according to their shapes are characterized by the close and inseparable relationship between geometry and structural behavior. Therefore, the choice of an appropriate geometry is the indispensable previous step in the conceptual design of these structures.
In this task, the selection of possible antifunicular geometries for the most common permanent load distributions are rather limited and, many times, non-structural criteria (functional adaptability, aesthetics, construction process, etc.) do not allow their use in order to guarantee the maximum use of the material.
In this context, this research studies the possibility of obtaining a structure without bending moments even if the geometry is not antifunicular for its permanent loads.
Indeed, this work presents a procedure, based on graphic statics, which demonstrates how a set of additional loads, introduced through an external prestressing system with post-tension elements, can eliminate the bending moments due to permanent loads at any plane geometry. This results to be an antifunicular structure that provides innovative answers related to architectural versatility and material optimization.
This graphic methodology has been implemented through a freely distributed software (EXOEQUILIBRIUM), where the structural analysis and geometric variation are included in the same interactive and parametric environment. The use of these tools allows more versatility in the research of new efficient forms, which is of great importance in the conceptual design of structures, let the engineer free from the limitation of the calculation and from the misunderstanding of structural behavior.
This research includes the application of these procedures to structures of any geometry and initial load distribution, as well as the study of different possible design criteria to optimize the position of the post-tensioning system. In addition, the methodology has been used in the project of models on a reduced scale and in the construction of a pavilion made entirely of cardboard, which has allowed obtaining a physical validation of the developed procedure.
In essence, this thesis significantly expands the range of possible antifunicular geometries and it opens up enormous possibilities for the design of structures that combine structural efficiency and architectural flexibility.
.
2018
|
Todisco, L; Stocks, E; León, J; Corres, H Enhancing the Structural Performance of Masonry Structures by Post-Tensioning Journal Article Nexus Network Journal, pp. 1–21, 2018. Abstract | Links | BibTeX @article{Todisco2018b,
title = {Enhancing the Structural Performance of Masonry Structures by Post-Tensioning},
author = {L Todisco and E Stocks and J León and H Corres},
doi = {10.1007/s00004-018-0374-z},
year = {2018},
date = {2018-01-01},
journal = {Nexus Network Journal},
pages = {1--21},
abstract = {textcopyright 2018 Kim Williams Books, Turin Despite the evident advantages of combining masonry with prestress, their joint use has been poorly exploited during the last decades. This paper claims the high potential of masonry as a primary load-bearing material when combined with post-tensioning. This work deals with arch footbridges and antifunicular structures. With respect to the first, this research illustrates the introduction of external loads by internal post-tensioning to favourably increase the axial forces in a masonry arch, and consequently improving its structural behaviour. With respect to the second, this work shows how bending moments in a non-funicular 2D curved geometry can be eliminated through an external post-tensioning system. In summary, this research strongly expands the range of post-tensioned masonry structures that exhibit a bending-free (or quasi bending-free) behaviour and, de facto, opens up new possibilities for designs that combine structural efficient solutions with traditional materials.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
textcopyright 2018 Kim Williams Books, Turin Despite the evident advantages of combining masonry with prestress, their joint use has been poorly exploited during the last decades. This paper claims the high potential of masonry as a primary load-bearing material when combined with post-tensioning. This work deals with arch footbridges and antifunicular structures. With respect to the first, this research illustrates the introduction of external loads by internal post-tensioning to favourably increase the axial forces in a masonry arch, and consequently improving its structural behaviour. With respect to the second, this work shows how bending moments in a non-funicular 2D curved geometry can be eliminated through an external post-tensioning system. In summary, this research strongly expands the range of post-tensioned masonry structures that exhibit a bending-free (or quasi bending-free) behaviour and, de facto, opens up new possibilities for designs that combine structural efficient solutions with traditional materials. |
2016
|
Todisco, Leonardo; Mueller, Caitlin Externally post-tensioned structures : Validation through physical models Inproceedings International Conference on Structures and Architecture, pp. 1144–1151, 2016, ISBN: 9781138026513. BibTeX @inproceedings{Todisco2016b,
title = {Externally post-tensioned structures : Validation through physical models},
author = {Leonardo Todisco and Caitlin Mueller},
isbn = {9781138026513},
year = {2016},
date = {2016-01-01},
booktitle = {International Conference on Structures and Architecture},
pages = {1144--1151},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Todisco, Leonardo Funicularity and Equilibrium for High-Performance Conceptual Design PhD Thesis Technical University of Madrid, Spain, 2016. Links | BibTeX @phdthesis{Todisco2016f,
title = {Funicularity and Equilibrium for High-Performance Conceptual Design},
author = {Leonardo Todisco},
url = {http://oa.upm.es/39733/},
year = {2016},
date = {2016-01-01},
school = {Technical University of Madrid, Spain},
keywords = {},
pubstate = {published},
tppubtype = {phdthesis}
}
|
Todisco, Leonardo; Corres-Peiretti, Hugo; Mueller, Caitlin Funicularity through External Posttensioning : Design Philosophy and Computational Tool Journal Article Journal of Structural Engineering, 142 (2), pp. 1–9, 2016, ISSN: 978-90-5363-042-6. Links | BibTeX @article{Todisco2016e,
title = {Funicularity through External Posttensioning : Design Philosophy and Computational Tool},
author = {Leonardo Todisco and Hugo Corres-Peiretti and Caitlin Mueller},
doi = {10.1061/(ASCE)ST.1943-541X.0001416.},
issn = {978-90-5363-042-6},
year = {2016},
date = {2016-01-01},
journal = {Journal of Structural Engineering},
volume = {142},
number = {2},
pages = {1--9},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
|
2015
|
Todisco, L; Fivet, C; Corres-Peiretti, H; Mueller, C Design and exploration of externally posttensioned structures using graphic statics Journal Article Journal of the International Association for Shell and Spatial Structures, 56 (4), pp. 249–258, 2015. Abstract | BibTeX @article{Todisco2015b,
title = {Design and exploration of externally posttensioned structures using graphic statics},
author = {L Todisco and C Fivet and H Corres-Peiretti and C Mueller},
year = {2015},
date = {2015-01-01},
journal = {Journal of the International Association for Shell and Spatial Structures},
volume = {56},
number = {4},
pages = {249--258},
abstract = {textcopyright Copyright 2015 by Leonardo Todisco, Corentin Fivet, Hugo Corres-Peiretti and Caitlin Mueller. Funicular structures, which follow the shapes of hanging chains, work in pure tension (cables) or pure compression (arches), and offer a materially efficient solution compared to structures that work through bending action. However, the set of geometries that are funicular under common loading conditions is limited. Nonstructural design criteria, such as function, program, and aesthetics, often prohibit the selection of purely funicular shapes, resulting in large bending moments and excess material usage. In response to this issue, this paper explores the use of a new design approach that converts non-funicular planar curves into funicular shapes without changing the geometry; instead, funicularity is achieved through the introduction of new loads using external post-tensioning. The methodology is based on graphic statics, and is generalized for any twodimensional shape. The problem is indeterminate, meaning that a large range of allowable solutions is possible for one initial geometry. Each solution within this range results in different internal force distributions and horizontal reactions. The method has been implemented in an interactive parametric design environment, empowering fast exploration of diverse axial-only solutions. In addition to presenting the approach and tool, this paper provides a series of case studies and numerical comparisons between new post-tensioned structures and classical bending solutions, demonstrating that significant material can be saved without compromising on geometrical requirements.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
textcopyright Copyright 2015 by Leonardo Todisco, Corentin Fivet, Hugo Corres-Peiretti and Caitlin Mueller. Funicular structures, which follow the shapes of hanging chains, work in pure tension (cables) or pure compression (arches), and offer a materially efficient solution compared to structures that work through bending action. However, the set of geometries that are funicular under common loading conditions is limited. Nonstructural design criteria, such as function, program, and aesthetics, often prohibit the selection of purely funicular shapes, resulting in large bending moments and excess material usage. In response to this issue, this paper explores the use of a new design approach that converts non-funicular planar curves into funicular shapes without changing the geometry; instead, funicularity is achieved through the introduction of new loads using external post-tensioning. The methodology is based on graphic statics, and is generalized for any twodimensional shape. The problem is indeterminate, meaning that a large range of allowable solutions is possible for one initial geometry. Each solution within this range results in different internal force distributions and horizontal reactions. The method has been implemented in an interactive parametric design environment, empowering fast exploration of diverse axial-only solutions. In addition to presenting the approach and tool, this paper provides a series of case studies and numerical comparisons between new post-tensioned structures and classical bending solutions, demonstrating that significant material can be saved without compromising on geometrical requirements. |
