fribourg s8 2009 constructive truths joint master of architecture till vallée ON STRUCTURE AND ARCHITECTURE A CIVIL ENGINEER‘S VIEW

Objectives The following is intended to Give a civil engineer’s view on the relations between structure and architecture To question the rationale between both Sketch potential strategies to question the readability of structures The following is… Highly subjective Largely incomplete Mainly a basis for discussions

The following is intended to

Give a civil engineer’s view on the relations between structure and architecture

To question the rationale between both

Sketch potential strategies to question the readability of structures

The following is…

Highly subjective

Largely incomplete

Mainly a basis for discussions

Defining structures In the context of the following, a structure is loosely defined as a physical object, or a system thereof, that enables people crossing voids, lift goods, defines space etc. It’s purpose of function is to supply the strength, stiffness, and rigidity to fulfill the aforementioned functions

In the context of the following, a structure is loosely defined as a physical object, or a system thereof, that enables people crossing voids, lift goods, defines space etc.

It’s purpose of function is to supply the strength, stiffness, and rigidity to fulfill the aforementioned functions

Defining structures Generally speaking: structures form parts of a work of architecture Structures are closely related to architecture, space and expression Structures can form the envelope, may control the inflow of daylight, potentially control the relation between the inside and the outside etc.

Generally speaking: structures form parts of a work of architecture

Structures are closely related to architecture, space and expression

Structures can form the envelope, may control the inflow of daylight, potentially control the relation between the inside and the outside etc.

Relationship between architecture and structure For classical Greek architecture, the architectural expression was strongly tied to the beams and columns, and their proportions With modernism, things changed e.g.: Perret and Le Corbusier separated constructive from functional/expressive elements Separation into purely structural and abstractly ae sthetic

For classical Greek architecture, the architectural expression was strongly tied to the beams and columns, and their proportions

With modernism, things changed

e.g.: Perret and Le Corbusier separated constructive from functional/expressive elements

Separation into purely structural and abstractly ae sthetic

Problems raised by modernism How to separate the structural elements from the aesthetical ones Where does the structure begin, and where does it end… While the answer might easy when it comes, e.g. to skelleton structures, it is not obvious for, e.g. a dome… The structure dome needs more than the topology dome

How to separate the structural elements from the aesthetical ones

Where does the structure begin, and where does it end…

While the answer might easy when it comes, e.g. to skelleton structures, it is not obvious for, e.g. a dome…

The structure dome needs more than the topology dome

How to sort out?

Sorting out by emphasis? National Gallery, Parma (1986) Guido Canali

National Gallery, Parma (1986)

Guido Canali

Refinement

Science vs. Technology? The purely structural aspect has to be separated into two components, that are not synonymous Scientific , as a theoretical answer to an optimization question involving solely the laws of nature Technological , as scientific + including boundary conditions imposed by e.g. manufacturing or any constraint imposed by “reality”

The purely structural aspect has to be separated into two components, that are not synonymous

Scientific , as a theoretical answer to an optimization question involving solely the laws of nature

Technological , as scientific + including boundary conditions imposed by e.g. manufacturing or any constraint imposed by “reality”

Little tangents… Iron wrought I-Beams, 1830’s IDEAL FORM, I 1 Independent of material OPTIMAL FORM, I 2 Ideal form + real material behavior CONSTRUCTIBLE FORM Optimal form + manufacturing constraints IMPLEMENTEND FORM Constructible form + cost analysis

IDEAL FORM, I 1

Independent of material

OPTIMAL FORM, I 2

Ideal form + real material behavior

CONSTRUCTIBLE FORM

Optimal form + manufacturing constraints

IMPLEMENTEND FORM

Constructible form + cost analysis

Little tangents… Britannia Bridge, 1850

Little tangents… I-Beams It’s seems nowadays obvious that the I-Beam developed from purely mechanical considerations… as an answer to maximizing I while minimizing A However, there is ample evidence, that in fact, manufacturability drove the development much more than theory…

It’s seems nowadays obvious that the I-Beam developed from purely mechanical considerations…

as an answer to maximizing I while minimizing A

However, there is ample evidence, that in fact, manufacturability drove the development much more than theory…

Explanation vs. Interpretation of structural form Using the laws of science and technology , cf. the difference made prior, we are usually able to explain how a structure is functioning However, we can sometimes only interpretate the architectural intention, using the context, certain functional and spatial relationships Southwark Station (1999) Jubilee Line, London. Architect: Richard MacCormac

Using the laws of science and technology , cf. the difference made prior, we are usually able to explain how a structure is functioning

However, we can sometimes only interpretate the architectural intention, using the context, certain functional and spatial relationships

“Aesthetics” Thus, there is a fundamental cognitive difference between the scientific / technological and architectural qualities So what makes a structure is coherent, or the cognitive experience pleasant ? In the following, purely considering solely structural aspects… Somewhere in northern Nevada Architect: better left unnamed… Column in the central nave. Architect; Jules Astric Église Notre-Dame du Travail (1902), Paris

Thus, there is a fundamental cognitive difference between the scientific / technological and architectural qualities

So what makes a structure is coherent, or the cognitive experience pleasant ?

In the following, purely considering solely structural aspects…

1 st wrap up

Structural form and it’s logic For civil engineers, structural form gravitates around central topics as Strength Stiffness Stability Durability in the broader sense In engineering practice, these topics are, as much as possible, orthogonalized Strength is attributed to the material Stiffness is a sectional quality Stability relates to static system Durability is related to detailing

For civil engineers, structural form gravitates around central topics as

Strength

Stiffness

Stability

Durability in the broader sense

In engineering practice, these topics are, as much as possible, orthogonalized

Strength is attributed to the material

Stiffness is a sectional quality

Stability relates to static system

Durability is related to detailing

What it is about

Three aspects At the heart of all discussions: material Defining efficiency: as a first design principle Adequacy of scale

At the heart of all discussions: material

Defining efficiency: as a first design principle

Adequacy of scale

Structural rationalism: Viollet-le-Duc What could establish unity in architecture, if not on the structure? Only by following the order of nature… can one conceive and produce according to the laws of unity… Each material has certain qualities and characteristics that “logically” produce certain forms… Every use of the material must be proportional to the object… When the scale changes, the architect must also change his mode of operation

What could establish unity in architecture, if not on the structure?

Only by following the order of nature… can one conceive and produce according to the laws of unity…

Each material has certain qualities and characteristics that “logically” produce certain forms…

Every use of the material must be proportional to the object… When the scale changes, the architect must also change his mode of operation

Structural rationalism: Frank Lloyd Wright From “ Entretiens sur l’architecture ” To bring out the nature of the material Let their nature intimately into your scheme Reveal the nature of the wood, plaster, brick or stone in your designs From “ The architectural record ” Materials not only have characteristics but also have ‘meaning’ Each material has it’s own message… speaks an own language

From “ Entretiens sur l’architecture ”

To bring out the nature of the material

Let their nature intimately into your scheme

Reveal the nature of the wood, plaster, brick or stone in your designs

From “ The architectural record ”

Materials not only have characteristics but also have ‘meaning’

Each material has it’s own message… speaks an own language

Structural rationalism: Louis Kahn Realization is Realization in Form, which means a nature. You realize that something has a certain order… If you think a brick… you consider the nature of brick: “What do you want, brick?” ÷ The brick’s answer: “I like an arch” Materials and their nature are inseparable…

Realization is Realization in Form, which means a nature. You realize that something has a certain order…

If you think a brick… you consider the nature of brick: “What do you want, brick?” ÷ The brick’s answer: “I like an arch”

Materials and their nature are inseparable…

Structural rationalism: Nervi Costruire correttamente Tactile sense and subconscious appreciation of the physical qualities of the materials… Employing materials according to their nature… they have a will of their own RC beams lose [their] rigidity and ask to be molded according to the line of the bending moments and shear stresses…

Costruire correttamente

Tactile sense and subconscious appreciation of the physical qualities of the materials…

Employing materials according to their nature… they have a will of their own

RC beams lose [their] rigidity and ask to be molded according to the line of the bending moments and shear stresses…

Opposite views Tschumi: those who advocate the “honesty of materials” are often motivated by ideological, rather than practical reasons Coop-Himmelb(l)au: … we want to keep the design moment free of all material constraints… but instead to define the feeling. disrupting a possible causal relationship between material properties and a ‘ resulting’ form

Tschumi:

those who advocate the “honesty of materials” are often motivated by ideological, rather than practical reasons

Coop-Himmelb(l)au:

… we want to keep the design moment free of all material constraints… but instead to define the feeling.

disrupting a possible causal relationship between material properties and a ‘ resulting’ form

Two main principles Form inherently resides in the material, and is made explicit by respecting the qualities and properties (the nature) of that material Form is conceived irrespectively of the material, and is as such free to evolve without preconditions for realization in a specific material However, there is still the ‘spirit’ of 1. , when looking at the detail level…

Form inherently resides in the material, and is made explicit by respecting the qualities and properties (the nature) of that material

Form is conceived irrespectively of the material, and is as such free to evolve without preconditions for realization in a specific material

However, there is still the ‘spirit’ of 1. , when looking at the detail level…

Global Form vs. Local Form

Sometimes, le bon Dieu est dans le détail The Portuguese Pavilion, Expo 98, Lisbon.

Sometimes, le bon Dieu est dans l’assemblage

Little tangent

2 nd wrap up

Why the world looks to easy to engineers Engineers can quantify efficiency On the lower level of structural efficiency, using structural mechanics But also on the level of technological efficiency, including ‘pricing’ We also agree on the difference between both The rules for both are known Structural efficiency by half a dozen of known formulæ Which I spare out here… even if, as an engineer, I was tempted to show them all

Engineers can quantify efficiency

On the lower level of structural efficiency, using structural mechanics

But also on the level of technological efficiency, including ‘pricing’

We also agree on the difference between both

The rules for both are known

Structural efficiency by half a dozen of known formulæ

Which I spare out here… even if, as an engineer, I was tempted to show them all

Pragmatics

Finally I could not resist… Structures are more efficient when …loads cause axial forces in the system rather than bending …compression forces are transported across short distances …structural members have optimized cross- sections …made locally more by triangulated trussing … made locally with pre- stressed members …etc. etc. etc.

Structures are more efficient when

…loads cause axial forces in the system rather than bending

…compression forces are transported across short distances

…structural members have optimized cross- sections

…made locally more by triangulated trussing

… made locally with pre- stressed members

…etc. etc. etc.

Basically said, we found our truth…

We also understand the relation between Efficiency and complexity At least as a spin-off of technological efficiency… Efficiency and scale What’s efficient on a large scale, might not at a smaller scale…

Efficiency and complexity

At least as a spin-off of technological efficiency…

Efficiency and scale

What’s efficient on a large scale, might not at a smaller scale…

Structural scale

Structural scale Overcoming the problem of structural scaling By changing the proportions – that is, to increase the structural depth relatively more than the span. Change the structural material – that is, to seek a material with a higher strength/stiffness-to-density ratio. Change the structural form, searching for relatively lighter, more efficient structures. Historically, an interesting way of overcoming the scale problem was by overlaying structural principles.

Overcoming the problem of structural scaling

By changing the proportions – that is, to increase the structural depth relatively more than the span.

Change the structural material – that is, to seek a material with a higher strength/stiffness-to-density ratio.

Change the structural form, searching for relatively lighter, more efficient structures.

Historically, an interesting way of overcoming the scale problem was by overlaying structural principles.

Structural scale

Structural scale A cantilevered seat at the Museum of Natural History, London. The cantilevering truss of Leppävaara sports stadium, Espoo, Finland (1985). Architects: the Building Design Department of the Technical Office of the City of Espoo/Pekka Kolari.

Aesthetics of the mechanical function Considering the aesthetics of structures from a mechanical point of view implies the appreciation of the capacity of materialized form to act structurally. An aesthetics of the mechanical function should embrace an aesthetics of materials and of scientific and technological processes. It invokes the concepts of material properties, of mechanical efficiency and of structural scale.

Considering the aesthetics of structures from a mechanical point of view implies the appreciation of the capacity of materialized form to act structurally.

An aesthetics of the mechanical function should embrace an aesthetics of materials and of scientific and technological processes.

It invokes the concepts of material properties, of mechanical efficiency and of structural scale.

Aesthetics of the mechanical function Structural form that ignores basic knowledge of the relationship between geometry and structural behavior, the result being an inappropriate lack of structural efficiency; Musée d’Orsay, Paris (1986). Architects Gae Aulenti and Act Architecture.

Structural form that ignores basic knowledge of the relationship between geometry and structural behavior, the result being an inappropriate lack of structural efficiency;

Aesthetics of the mechanical function Structures that resolve unsatisfactorily the relationship between material properties and structural form. This applies to both the global and the local level of structural form, and may also involve questions of structural scale; École d’Architecture de Lyon (1987). Architects Jourda and Perraudin.

Structures that resolve unsatisfactorily the relationship between material properties and structural form. This applies to both the global and the local level of structural form, and may also involve questions of structural scale;

Aesthetics of the mechanical function Over-simplification of form in larger- scale structures, displaying less structural efficiency than is considered appropriate; Coutts Bank, London (1978). Architect Frederick Gibberd.

Over-simplification of form in larger- scale structures, displaying less structural efficiency than is considered appropriate;

Aesthetics of the mechanical function A complexity of form that seeks inappropriately high structural efficiency in a structure of a small scale, the result being a lack of technological efficiency. Sainsbury’s, Camden, London (1988). Architect Nicholas Grimshaw.

A complexity of form that seeks inappropriately high structural efficiency in a structure of a small scale, the result being a lack of technological efficiency.

Some example Seen through engineer’s eyes

Hamar Olympic Amphitheatre Hamar Olympic Amphitheatre, Norway (1993). Architects HRTB, structural engineers Grøner AS.

Fuhlsbüttel Airport Fuhlsbüttel Airport, Hamburg (1993). Architects von Gerkan, Marg and Partners. structural engineers ARGE Kockjoy–Schwarz + Dr Weber.

Novartis Roof T. Keller, C. Haas, and T. Vallée, „Structural concept, design and experimental verification of a GFRP sandwich roof structure“, Journal of Composites for Construction, no. 12/4, pp. 454-468, 2008.

The Millennium Dome The Millennium Dome, Greenwich, London (1998). Architects Imagination Ltd and Richard Rogers Partnership.

Stuttgart Airport Terminal 1 Stuttgart Airport Terminal 1 (1991). Architects von Gerkan, Marg and Partners.

Schulhaus Leutschenbach

Cantonal Grammar School, Wil SG (2004) Cantonal Grammar School in Wil SG (2004). Staufer & Hasler architects.

German Pavilion Barcelona, 1929

German Pavilion Barcelona, 1929

German Pavilion Barcelona, 1929

Learning Center, EPFL SANAA Kazuyo Sejima+Rye Nischizawa,Tokyo V Ongoing works

Learning center, EPFL

Chapelle St. Loup, VD

Chapelle St. Loup, VD There are mathematical rules for origami crease patterns: Crease patterns are two colorable at any vertex The number of valley and mountain folds always differ by two in either direction At any vertex, the sum of all the odd angles adds up to 180 degrees, as do the even. A sheet can never penetrate a fold Significantly, paper exhibits zero Gaussian curvature at all points on its surface, and only folds naturally along lines of zero curvature. Almost any laminar material can be used for folding; the only requirement is that it should hold a crease.

There are mathematical rules for origami crease patterns:

Crease patterns are two colorable at any vertex

The number of valley and mountain folds always differ by two in either direction

At any vertex, the sum of all the odd angles adds up to 180 degrees, as do the even.

A sheet can never penetrate a fold

Significantly, paper exhibits zero Gaussian curvature at all points on its surface, and only folds naturally along lines of zero curvature.

Almost any laminar material can be used for folding; the only requirement is that it should hold a crease.

Some conclusive thoughts Structural, and technological logic certainly helps ‘reading’ the architecture Structures that follow certain minimal <formal> requirements are less likely to lead to cognitive dissonance Subordinating architecture to the structural logic, or keeping the design moment free of all material constraints, remains an open question For which latter formal requierements might still be formulated afterwards, and/or at different levels

Structural, and technological logic certainly helps ‘reading’ the architecture

Structures that follow certain minimal <formal> requirements are less likely to lead to cognitive dissonance

Subordinating architecture to the structural logic, or keeping the design moment free of all material constraints, remains an open question

For which latter formal requierements might still be formulated afterwards, and/or at different levels

Thank you for your kind attention I’ll do my best to answer any of your questions