Special Issue by Denis Zastavni
Applied Sciences, 2021
The current Special Issue focuses both on recent advances in graphic statics and on the examinati... more The current Special Issue focuses both on recent advances in graphic statics and on the examination of the old graphical methods from a more modern viewpoint. Suitable topics include but are not limited to the following:
Applications of graphic statics to the mechanics of
historic masonry constructions;
Historical approaches using graphic statics to
design structures;
Thrust network analysis;
Extension of graphic statics to 3D structures;
Recent advances in graphic statics;
Applications of graphic statics to the mechanics of
trusses;
Applications of graphic statics to bending analysis
and design;
Applications of graphic statics to concrete
structures;
Applications of graphic statics to timber structures;
Numerical tools using graphic statics;
Analytical and computational graphic statics;
Structural optimization using graphic statics;
Design of funicular forms;
A modern interpretation of the historical method of
graphic statics.
We would be grateful to you if you could spread this
information to anyone who might be interested.
Deadline for manuscript submissions: 30 June 2021
Papers by Denis Zastavni
Rilem bookseries, Sep 3, 2023
IABSE Workshop, Helsinki 2017: Ignorance, Uncertainty, and Human Errors in Structural Engineering, 2017
The aim of this paper is to develop a complementary method to the numerical approaches proposed i... more The aim of this paper is to develop a complementary method to the numerical approaches proposed in the literature on the subject, which will help in assessing the constitutive dimensions of structural robustness at the conceptual stage. Based on geometrical thinking, this method defines robustness as the ability of a structure to maximise the rearrangement of its internal forces. This can be expressed graphically by admissible geometrical domains. The purpose and extent of this new approach are summarised and illustrated by the detailed robustness analysis of two case studies. The areas obtained for the admissible geometrical domains are then compared with values of the minimal load path and with structural stiffness, in order to decide on the right modelling strategy.
info:eu-repo/semantics/publishe
This paper extends the theoretical developments of the ongoing research on 2D internally and exte... more This paper extends the theoretical developments of the ongoing research on 2D internally and externally statically indeterminate networks, using graphic statics. Specifically, parametric force diagrams are used for the analysis and optimization of strut-and-tie networks inscribed inside continuous structures. A simple wall is used to exemplify a series of optimization strategies that can be pursued while designing reinforced concrete structures. These help designers to reduce the overall cost of the structure while minimizing the overall quantity of reinforcement and optimizing the distribution of the compressive forces in the concrete struts
Le bois, produit de la forêt, a été de tous temps une ressource majeure pour la construction et p... more Le bois, produit de la forêt, a été de tous temps une ressource majeure pour la construction et pour l'homme, ce qui a justifié le maintien, puis l'extension des forêts. Il est matériau de prédilection pour les charpentes, les panneaux d'ossatures, les bardages, les planchers, le mobilier. Cependant, ses usages en construction ont toujours représenté une dimension technique affirmée. Aujourd'hui, le bois permet des bâtiments plus légers, des fondations réduites ; un impact carbone limité ou positif ; la rapidité de construction ; des bâtiments durables et recyclables, à haute performance énergétique... puis il y a toute la chaleur du matériau. La construction en bois est constamment le contexte d'innovations technologiques et la maîtrise technique croissante du matériau mène à réinventer notre habitat.... et peut-être les villes en bois de demain
Robert Maillart a contribue par son œuvre a faire du beton arme un materiau nouveau, avec des str... more Robert Maillart a contribue par son œuvre a faire du beton arme un materiau nouveau, avec des structures a l'expressivite jusque-la jamais rencontree. A un moment-cle de l'emergence de grands ouvrages en beton arme, Maillart propose une serie de systemes et de typologies structurales declinees de facon nouvelle en beton : le caisson, les ponts a trois articulations, les arcs raidis, les planchers-champignons et d'autres ouvrages plus complexes encore. L'etude de ces structures nous mene a considerer la conception structurale en beton dans un contexte elargi, mais qui prend un sens nouveau et tout particulier aujourd’hui.
La conception des structures en béton est aujourd'hui solidement adossé à des outils nombreux... more La conception des structures en béton est aujourd'hui solidement adossé à des outils nombreux qui autorisent à ne plus laisser plus place à l'expectative. D'une part nos outils contemporains ont levé la quasi-totalité de difficulté mathématique à analyser des configurations ...
By reviewing some of the reinforced-concrete structures built in the early 20th century, this pap... more By reviewing some of the reinforced-concrete structures built in the early 20th century, this paper questions the geometrical aspects surrounding their design. It is well established that in the case of Robert Maillart’s designs, he relied on the logic of thrust lines, as was the case for masonry bridges that were provided by funicular polygons and graphic statics. Maillart also relied on trial sketches to define the mechanical features of successive sections of the bridge and on geometrical considerations to define the line of his bridges. In the case of his stiffened arch bridges, geometrical considerations were confined to following with almost regular thickness the trajectory of the thrust line. However, for some of them and for the whole family of three-hinged arch bridges, formal and geometrical considerations applied, for which some rules are presented here, and their evolution can be seen over time. The challenge in the geometrical organization of concrete around the thrust line is to equilibrate the stresses and manage the group of possible thrust lines depending on various loading cases. A well-designed concrete geometry avoids tensile stresses, which guarantees relatively long-lasting structures. With Maillart’s approach, an almost completely geometrical approach to design is encountered, since forces are also managed by geometry within the scope of graphic statics. Regular geometries and isostatic and symmetrical structures guarantee the possibility of undertaking a complete analysis using graphical approaches. However, when hyperstaticity or lateral forces are taken into account, the analysis is not as straightforward. This paper examines the extent to which the geometrical approach provides answers to these issues, with various hypotheses such as elastic analysis or a plastic lower-bound approach. The paper concludes by questioning this approach to the design of concrete structures in the early 20th century and its relative interest for structural design today.
With a summary of what the authors consider to be the fundamental challenges encountered in desig... more With a summary of what the authors consider to be the fundamental challenges encountered in designing structures, this paper aims to explore elements of Maillart's approach to designing structures to show how these ends are encountered naturally as soon as the basis of the design approach is soundly established. While showing how Maillart proceeded to conceptualise and design the Zuoz Bridge (1901), the Salginatobel Bridge (1929), the Vatschielbach Bridge (1923) and the Chiasso Shed (1924), the main features of his methods can be summed up as follows: after carefully establishing structural behaviour, the lateral form was defined by developing a design from a series of graphic statics drawings, while algebraic calculations allowed him to determine the transversal section and details of the plan and profiles. It may be one of the first occasions when graphic statics have been used as a heuristic method to discover the right form, i.e. as a design tool for morphogenesis. Studying the geometry of the Chiasso Shed demonstrates the way Maillart used graphic statics-a powerful tool for equilibrating the structure with the aim of placing materials in the right position within a structural system. As Maillart was also a builder, he integrated aspects into his design taken from construction, which made his projects particularly costeffective. Finally, we conclude from this analysis of Maillart's work that there is a senseduring the design process-of giving priority to thinking globally about form and the status given to concrete in order to come up with efficient and reliable designs.
<u>Third International Congress on Construction History</u>, Brandenburg University of Technology Cottbus, Germany , 20th-24th May 2009, 2009
This paper attempts to reveal the specific nature of the work of Robert Maillart [1872-1940], aft... more This paper attempts to reveal the specific nature of the work of Robert Maillart [1872-1940], after carefully reviewing the historical context of concrete design. Maillart’s favourite material was reinforced concrete, and he devised forms that synthesised all the characteristics of a relevant structure. He succeeded by establishing a clear status for each material used – concrete and reinforcement steel – which allowed him to define the geometry of his structures correctly. This is demonstrated here by an analysis of the design drawings for the Salginatobel Bridge and the Chiasso Shed. These examples offer clarification of the use he made of calculation and graphic statics for design purposes. We conclude with the specificity of his approach as a singular vision of how (reinforced) concrete can be used within a structural scheme, which in turn allows an original, expressive structure to be produced of great relevance and reliability.
Geometrical domains characterising the degrees of freedom of a structural system within the conte... more Geometrical domains characterising the degrees of freedom of a structural system within the context of Maxwell’s reciprocal representation of force and geometry are likely to provide indicators of the constitutive elements of structural robustness. Structural robustness is defined as the “insensitivity to local failure”. This definition emphasises the structure’s capacity for force redistribution and the possibility of finding alternative load paths in a structure. Features linked to resistance and the redistribution of forces are likely to be modelled by load path, struts and ties or thrust lines, close to geometrical thinking. Since most methods proposed today for assessing the robustness of structures are based on probabilistic approaches, they are of limited interest for the design phase. Of the few approaches that have adopted a deterministic formulation, all provide a type of survey that is based on an in-depth analysis of the structure once it has been designed, according to specific scenarios. A central challenge should be to manage the issue of robustness earlier during the design process, or even to be able to interact with a model of the future structure in order to adjust the features of robustness. This paper explores the ability of geometrical domains to assess some of the relevant elements of structural robustness in terms of design in order to characterise the capacity of structures to redistribute forces. It compares indicators linked to the area of these domains. Based on case studies, this quantification of the structural provision is then compared with indices of deterministic and energetic criteria currently proposed in literature to quantify structural robustness.
In 1879, then 23-year-old Maurice Koechlin became the lead structural engineer of Gustave Eiffel’... more In 1879, then 23-year-old Maurice Koechlin became the lead structural engineer of Gustave Eiffel’s construction company founded 13 years before. Together, they pushed the boundaries of steel and iron structural design. They were responsible for the design of the Garabit viaduct (1879-1884), the Tarde viaduct (1881-1884), the inner reinforcement of the Statue of Liberty (1881-1886) and the 300 meter-high tower in Paris (1884-1889). In 1900, Koechlin succeeded Gustave Eiffel to head the company, a position he held until his retirement in 1940. Whereas Maurice Koechlin’s engineering works are known by many and considered as masterpieces, very little is known about his written scientific contribution. This paper first attempts to draw a comprehensive list of Koechlin’s publications. A total of 28 have been identified among which one book and 14 papers provide original findings on struc-tural engineering science. Written between 1884 and 1925, they address the resolution of specific structural problems using graphic statics or numerical methods, they develop the design process of structures built by the Eiffel Company or they describe pioneering implementations for steel. As this original survey sheds new lights on Koechlin’s research interests and their chronolo-gy, the paper also restates Maurice Koechlin’s influence on the introduction of graphic statics in French-speaking Europe and further contextualizes the collaboration between Maurice Koechlin and Gustave Eiffel and the contribution of Maurice Koechlin to the Societe de constructions de Levallois-Perret.
La conception des structures en beton est aujourd’hui solidement adosse a des outils nombreux qui... more La conception des structures en beton est aujourd’hui solidement adosse a des outils nombreux qui autorisent a ne plus laisser plus place a l’expectative. D’une part nos outils contemporains ont leve la quasi-totalite de difficulte mathematique a analyser des configurations structurales extremement sophistiquees. D’autre part, l’experience accumulee, de nombreux tests et le processus de codification du calcul du beton entame au debut des annees 1900 apportent des reponses quant aux strategies de modelisation et aux procedures de verification a suivre. En d’autres termes, quelque soit la complexite de la question structurale en beton arme ou precontraint, dans les conditions de mise en oeuvre les plus courantes, les outils theoriques et informatiques permettent raisonnablement d’esperer qu’une solution sera atteinte sans encombre, ou si peu. Notre approche contemporaine du calcul et du dimensionnement est base sur l’analyse structurale. La forme est donnee par le contexte, l’architecte, une experience, une reference... L’analyse structurale permet de decrire la reponse structurale dans la configuration geometrique et mecanique dans laquelle l’analyse a ete initiee. Les efforts permettent alors de dimensionner les elements structuraux qui composent le projet. Sitot que les caracteristiques geometriques de la configuration structurale s’en trouve modifie, l’analyse peut devoir etre reiteree. La solution la 'meilleure' peut vouloir etre recherchee et la methode devient iterative : c'est l’optimisation structurale. Les caracteristiques de la solution optimale sont se sont parfois singulierement ecartees de celles qui etaient recherchees au travers de la premiere formulation formelle ( geometrique ). Cette approche ne questionne pas la forme, les fondements, le point de depart de l’approche. Elle n’est cependant pas unique. Il existe des exemples notables d’inversion de cette sequence logique avec des resultats reellement probants. En lieu et place de la sequence classique : forme > analyse > efforts > ( comprehension du comportement structural > ) dimensionnement ( adaptation de la forme ) ; une autre sequence a ete mise en oeuvre par certains maitres es structures. On rencontre chez l’ingenieur Robert Maillart la sequence suivante : definition du contexte structural ( charges et champs des possibilites d’appui ) > definition / choix du comportement structural > dimensionnement correspondant et definition de la forme simultanes. L’analyse structurale est sortie du coeur de la sequence et peut meme devenir accessoire en fin de processus ou elle est parfois employee pour simple verification. Les adaptations geometriques n’ont pas lieu d’etre ( le dimensionnement est direct et unique pour assister la definition de la forme ). La forme est la consequence directe du projet de l’ingenieur... projet qui reside dans la conception du comportement structural. Le concepteur a garde la main sur le processus et sur la definition de la forme ; le calcul est un auxiliaire. La maitrise du processus de conception est totale. Pour proceder de la sorte, il faut connaitre la relation intrinseque qui relie la geometrie, la matiere et ses proprietes et le comportement structural, ainsi que la maniere d’agir sur l’un( e ) par l’intermediaire d’un( e ) autre. En d’autre termes, il est question d’en revenir aux fondements ou aux fondamentaux. Il faut aussi que le concepteur dispose de methodes pour controler le passage de la forme aux efforts. Le principe de reciprocite en est un, qui a ete theorise par James Clerk Maxwell en 1864. Il a ete implemente en outil notamment pas Cremona en l’appliquant a la statique graphique inauguree en tant que science mecanique par Culmann. Maillart fut un maitre dans le maniement des outils de la statique graphique mais aussi d’autre concepts tout aussi elabores qui font aujourd’hui partie de l’arsenal de l’ingenieur en structures... pour autant que le regard porte sur la question structurale autorise a activer les differents leviers dont dispose le concepteur pour parfaire son projet.
Cette recherche developpe un outil de modelisation et de calcul graphique destine a accompagner l... more Cette recherche developpe un outil de modelisation et de calcul graphique destine a accompagner les ingenieurs dans leur travail de conception de structures lors de la toute premiere mise en place des definitions formelles et physiques. Ce document est presente en trois parties. Dans un premier temps il analyse l’etat actuel de la pratique de la conception structurale. Motive par cet examen, l’outil est ensuite defini en compagnie des concepts qu’il manipule. Une manipulation basique de l’outil est finalement illustree.
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Special Issue by Denis Zastavni
Applications of graphic statics to the mechanics of
historic masonry constructions;
Historical approaches using graphic statics to
design structures;
Thrust network analysis;
Extension of graphic statics to 3D structures;
Recent advances in graphic statics;
Applications of graphic statics to the mechanics of
trusses;
Applications of graphic statics to bending analysis
and design;
Applications of graphic statics to concrete
structures;
Applications of graphic statics to timber structures;
Numerical tools using graphic statics;
Analytical and computational graphic statics;
Structural optimization using graphic statics;
Design of funicular forms;
A modern interpretation of the historical method of
graphic statics.
We would be grateful to you if you could spread this
information to anyone who might be interested.
Deadline for manuscript submissions: 30 June 2021
Papers by Denis Zastavni
Applications of graphic statics to the mechanics of
historic masonry constructions;
Historical approaches using graphic statics to
design structures;
Thrust network analysis;
Extension of graphic statics to 3D structures;
Recent advances in graphic statics;
Applications of graphic statics to the mechanics of
trusses;
Applications of graphic statics to bending analysis
and design;
Applications of graphic statics to concrete
structures;
Applications of graphic statics to timber structures;
Numerical tools using graphic statics;
Analytical and computational graphic statics;
Structural optimization using graphic statics;
Design of funicular forms;
A modern interpretation of the historical method of
graphic statics.
We would be grateful to you if you could spread this
information to anyone who might be interested.
Deadline for manuscript submissions: 30 June 2021