Booklet: Farady Pavilion (2012)

Faraday Pavilion

Roskilde Festival 2012, Denmark CITA: Centre for IT and Architecture Royal Danish Academy of Fine Arts, School of Architecture

Supported by: Det Frie Forskningsråd (FKK) – Postdoctoral Grant ‘Designing Material, Materialising Design’ for Paul Nicholas 2011-2012

Faraday Pavilion Roskilde Festival 2012

Collaborators, Participants, Sponsors Collaborators: Paul Nicholas, Ali Tabatabai Engineering: Christoph Gengnagel, Elisa Lafuente Hernรกndez (UDK) Participants: Martin Tamke, David Stasiuk, Matthew Gilbert, Andrius Vilcinskas, Kristjana Sigurdardottir, Henrik Evers, Irina Maximovich, Karl Tรถrnfeldt, Hollie Gibbons, Morten Myrup, Peter Houghton, Raphael Hilz, Niels Brix, Ben Lucraft Sponsors: Fiberline Composites, Hempel Paint

Research Question This project asks how bending performance might be incorporated within a digital model to design, simulate and build a bending-active network structure. It investigates the capacity of a force-based modeling approach to nest descriptions of material behaviour at multiple scales, to incorporate bending, to closely match the analysis and onsite assembly process. The approach to material-oriented digital simulation developed during the project links a top-down design intent with a bottom up understanding of material behaviour.

Traditional building structures facilitate load bearing through a correlation of compressive and tensile forces passing loads linearly through a building envelope that is

considered to have failed if it bends. In contrast, bending active structures utilize a material’s capacity to bend elastically to generate curved geometries from initially straight or planar building elements. Bending can be used strategically to allow quickly built, light and strong structures to be made from continuous straight profiles. However, as bending is typically absent from building structures, so has its description been absent from architectural representation and simulation tools. Conceptually, approaches that incorporate bending as part of the design process shift the understanding of material performance away from the absolute (ie. strength and lightness) and towards the capacity of a material for specification, variation and negotiation.

The project took point of departure in a brief to provide a seating and relaxation space for the 2012 Roskilde Festival.

Working with Fiberline’s 40mm fibre reinforced polymer (FRP) structural section, and exploring FRP’s high capacity for both bending and strength, the design comprises three seating ‘poles’ which generate a larger field of approximately 30x40m, whose extents and geometry are defined by 7 FRP gridshells.

The research asks: How can the property of bending, understood at multiple scales, be incorporated within a force-based modeling approach?

How can incremental assembly be incorporated within the simulation of bending-active network structures?

How can the negotiation of bottom-up and top-down parameters generate a gridshell topology? http://cita.karch.dk

Faraday Pavilion Roskilde Festival 2012

DEFINITION

DEFORMATION

LOCKING

Mannheim Multihalle

Bending Active Gridshell Structures The productive use of the elastic behaviour of materials has a history in vernacular architecture, yet only few examples have been constructed in 20th century, the Mannheim Gridshell being the most prominent example (Happold 1975). Here, elastic deformation was utilised as an economic construction method for double curved shell structures which takes advantage of ease of construction, long continuous elements, and simple connections.

While grid shells with short members theoretically do not experience bending forces, gridshells with continuous elements must consider bending. Grid shells are particular in that a key element of their erection process is to exert forces on material to deform it into a final shape. For this reason, they must be

materially flexible enough to deform and bend easily, with the capacity to remain elastic. For this reason timber has been the most used material, and FRP (with greater bending capacity than timber) now holds great interest.

Gridshell geometry can be determined via several methods: formfound using hanging models, geometrically, or computationally as the result of an equilibrium of applied shaping forces, internal bending moments and the forces transferred from one element to another (Lafuente Hernรกndez & Gengnagel). This means iteratively simulating the bending of the shell as it will be bent on site. The traditional approach is to define an initial flat grid that is then deformed into a double curved 3D form through the application of shaping forces and finally locked into position. To allow this

transition to take place, the grid topology has to be deformable and to begin in an inital relaxed state: these constraints restrict the geometries and topologies that are possible.

To explore an alternative approach, the construction process used here is one of incremental erection, and the geometry of the gridshell is not predefined. Instead elements are simulated individually using springs and bending constraints. The placement and path of elements is determined by a desired target geometry and a form-finding process that incorporates the bending capacities and behavioural tendencies of the FRP tubes into a digital design model.

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Faraday Pavilion Roskilde Festival 2012

Scale & Multiscale Working with composite materials and structures foregrounds the notion of scale, and of interdependency between scales. Scale is such a pervasive element of architectural practice that it is perhaps not obvious that considering several scales simultaneously can have substantial value. While approaches that link multiple scales do not exist as standard architectural tools, modeling concepts have been developed within the associated domains of material science and engineering. One of the key interests of this research is to transfer one of these concepts, multi scale modeling, to architecture, drawing from but not being limited by its application in other domains.

For material scientists, the Micro, Meso, Macro scales may all exist well below typical architectural scales. But for scientists studying geo-morphological processes, the Micro scale is defined as mm to cm, the Meso as m to km, and the maco as km to 10km, while for meteorological scientists, the Micro scale extends up to 2km, and the Meso scale up to 2000km. Recognising that instead of being explicit, scales are relational, Miyamoto proposed the three characteristic scales of D1, D2, and D3, where D1<D2<D3 (Miyamoto 1999). Within architectural design, these scales might be identified as the structure, the element and its material, with different descriptive methods capturing behaviour and performance at each scale, each valid within a certain bounds. These might include include metrics from direct experiment, equations, geometric models and force-based models.

Multiscale models link a scalar hierarchy of different methods together to simulate material and structural performance.

They pose the question of crafting associations between these different scales. At the macro scale, the problem is to achieve some desired performance under loading. At the micro scale, the problem is to identify the best local configuration. Through parameters that are both top down (the constraints, loads and goals) and bottom up (forces, stiffness matrices, etc), this project is able to explore material variation directly linked to formal variation, without being limiting the design space to material optimisation.

At the scale of the structure stability is important, and that the target plan geometry is maintained as much as is possible recognising material limits.

STRUCTURE

I θ

E

MATERIAL

ELEMENT

θ2

H

θ1

At the material scale the FRP tubes have a specific Youngs Modulus that is determined by the volume ratio of glass fibre and polymer matrix, and a set 40mm section. This gives a specific local stiffness, and a minimum local bending radius.

Beyond this radius will the matrix will snap.

Here the type of bending and the relationship between the length of each pole and its capacity for deflection becomes important. The longer the pole, the easier it is to deflect. If it is too short the assembly team is not physically able to push it into place, and the element will store a significant amount of energy that will potentially deform the structure. http://cita.karch.dk

Faraday Pavilion Roskilde Festival 2012 Områderne deler Roskilde Festival op i forskellige Villages, Zones &

r, Villages ies

Cities med hver deres tema for at gøre oplevelsen i det pågældende område så unik som muligt og samtidig understrege vores tværsektionelle fokus og indhold.

Sustainable Zone

Street City Entrance Platform

Backstage Village

Social Zone Orange Zone

Gloria Zone

Urban Zone Sonic Zone Entrance West

Graffiti Zone

Game City

Poor City Entrance East

Radio City Restricted Parking

Arena Zone

Trade Zone

Art City Cinema City Green City

Swim City

Roskilde Festival: Zones and Cities

Dream City

DESIGNMANUAL / ROSKILDE FESTIVAL 2012

Toilet 92-10

92-10

05-03

05-03 05-03

10-11 10-11 10-11 10-11

05-03A

10-11

10-11

10-11

50 m

92-10

10

-1 1

Roskilde Installation 2012 Sonic Zone - concept & references brandskel 10 m

40 m

Pavillon

ROSKILDE FESTIVAL - 2012 06 03

10-11

06-06

11-506C 11-509D

XL

10-05

3 stk.

08-12

06-06

brandskel 8 m

06-06 06-06 06-06

10-05

Sejl

√òL

k√∏l

√òl tank

m

Telcon

50

Råstof Roskilde

The installation site is 50m x 40m, and is located near the Pavilion stage. It will be present for the full period of the 2012 Roskilde Festival.

l 8.

Lager

YourSpace

ske

Your Space

Site plan

nd

bra

Pavilion Site in Sonic Zone

http://cita.karch.dk GAS

Toilet

Faraday Pavilion Roskilde Festival 2012

Design Concept The Faraday Pavilion, designed for Roskilde Festival 2012, is an installation that provides a place for people to rest, to meet, to eat and to socialize between concerts. The pavilion creates a space to sit on benches or to lie on the grass that is protected from the large surrounding crowds. , comprises three seating ‘poles’ which generate a larger field of approximately 30x40m, whose extents and geometry is defined by an FRP gridshell. At night, programmed lighting extends the pavilion’s usability and identity.

The design draws conceptually on the investigations and theories of Michael Faraday, who pioneered the study of electricity and magnetism. His work introduced for the first time the notion of the field, and that a space that seemed physically empty in actual fact contained energy and momentum. To represent the field, Faraday

introduced the notion of lines of force, which he also believed had a real, physical manifestation. We now know that this is not true, but the conceit that it might be drives the design and geometric definition of the pavilion.

The pavilion comprises of 3 positively charged ‘attactors’, which provide seating areas and located activities such as DJs within them, and a much larger field which defines a less formal area of inhabition that is protected from the the large flows of people within the site.

As such, it attempts to secure a large area with very little material.

While there are distinct entrances, the porosity of gridshell allows people to enter and exit the structure where they wish. During the design process, a computational model that calculated fieldlines given a set of input points was used to develop and explore

different plan configurations. The resultant 2D plan geometry becomes the target for the subsequent 3D, materially informed simulation process.

Plan Geometry: Simulation Sequence

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Faraday Pavilion Roskilde Festival 2012

ELEMENT SPRING

BEND CONSTRAINT

PHYSICAL TEST CATENARY CURVE SPRINGS AND HINGES FEA SIMULATION

From 2D to 3D - Encoding Elastica Behaviour The elastica, Latin for a thin strip, is the curve that most accurately describes the bending of a long thin piece of material. This is the curve that minimises bending energy over the length of an elastic curve, given specified endpoint conditions. The thin strip stores elastic potential energy as it is deformed. This energy is not distributed equally, but increases towards the middle where it reaches a maximum. If this energy exceeds the bending radius of the material, the strip will break.

There are many approaches to the elastica. The mathematical development of equations for solving the curve were developed by Euler and Bernouli. Force-based solutions are also possible using Finite Element Analysis (FEA) and physics engines. Using a physics engine, a combination of springs and hinge constraints allows for

the simulation of 3D bending. This approach is used here, where each element is defined as 16 nodes connected by 15 springs.

Groups of 3 nodes are connected via a bend constraint, which resists bending acting on an angle defined by 3 points. This definition was compared to the results of physical testing, as well as against the curve generated by FEA using Karambaâ&#x20AC;&#x2122;s large deflection analysis, and found to match both very closely. Combined with a local calculation of utilisation, this approach incorporates material behaviour at both a local and element level.

not near elastica

near elastica

very near elastica

near elastica

plan

base

Structural Concept

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Faraday Pavilion Roskilde Festival 2012

RADIAL ELEMENTS

TRANSVERSE ELEMENTS

NETWORK STRUCTURE

Modeling Sequence The modeling process is developed so that design, analysis and assembly are all matched as closely as possible. It sequentially determines radial and transverse FRP elements, and then simulates overall network behaviour. Each FRP element is defined by nodes connected by springs and hinges. The springs act to control the length of the element, while the hinges impose resistance and the correct bending behaviour. The starting lengths of each radial element are determined through approximation by a catenary curve, while the length of the transverse elemetns is determined by the simulation.

To match the desired target geometry, one end of each element is moved inwards, inducing bending, while the elements are locally constrained to constraint surfaces that are extruded from the 2D target plan. The strength of the surface constraint is dependent on the local measured bending radius, and is reduced as the bending radius approaches a minimum. Within the simulation, the geometric definition of each radial element therefore emerges from the negotiation of the elementâ&#x20AC;&#x2122;s local utilisation, its natural minimum energy bending behaviour, and the plan definition that acts as a target geometry.

CONSTRAINT SURFACE SIMULATED ELEMENT

PLAN CURVE

t=0

t = 25

t

t = 75

t = 100

t = 125

t = 150

t = 175

t = 200

Simulation of Radial Elements

=

50

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Faraday Pavilion Roskilde Festival 2012

Deviation from Target Shape

t=0 Once the radial elements are generated, the transverse elements are constrained to them and the edges but nothing else. The path of these transverse elements is then determined by solely by material bending and length parameters (tubes tend towards a length that is possible to bend by hand, on site). In this way, the geometry of the gridshells does not follow a standard grid, but instead is determined by a form-finding process that incorporates the bending capacities and behavioural tendencies of the material into a digital design model.

t = 100

t = 200

When both the radial and transverse elements are defined, springs are introduced at each node point to enforce a geometric separation, and the entire structure is simulated as a network free from any artificial constraints.

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Faraday Pavilion Roskilde Festival 2012

Structural Engineering - incremental bending simulation in Sofistik

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Faraday Pavilion Roskilde Festival 2012 Maximum Deformations

64.0

45.8

8.10

41.6

196.3 177.7 158.6 39.1 137.0 11.5

115.9 135.9 41.5 93.5

106.2

15.0

19.2

16.6

18.5

106.1 34.1125.6

19.3

21.5

44.5

7.80

35.7

22.9

38.6 54.0

33.4

25.4

43.3

67.7

63.6

75.5 65.6

49.6

75.6

MAX= 220.6

78.7

70.1

46.9 114.9

23.7

36.0

8.79 9.53

192.7

48.7

32.2 28.7

23.0 16.4

168.5 13.6

50.5

22.7 27.1

92.1 161.8

136.6

-5.00

27.3

50.5 101.4 102.8 82.5

22.249.2

20.0

97.3

94.6

10.1 4.66

28.6 34.2

6.05

42.8

2.37

88.2

48.6

111.3

38.0

98.0

17.1

61.4

5.26

FE-Model with deformations, exaggerated by a factor of 10

-10.00

69.2

-15.00 20.00

Properties of the profiles: E-Modul = 25GPa / Diameter = 40mm, Thickness = 3mm

Y

15.00

10.00

Knotenverschiebung Vektor, nichtlinearer Lastfall 100 EGZ= -1.00 sum_PZ= -2.29 kN

ZX

5.00

0.00

. , 1 cm im Raum = 229.7 mm

(Max=220.6)

m

M 1 : 94 X * 0.833 Y * 0.987 Z * 0.578

Max deformations are to be found on the edges with a maximum of 22cm.

Maximum Stresses 133.0 129.5

Model II: Connections between radial and transverse beams modelled as pin joints.

Ground supports have been modelled as fixed bearings.

110.6 107.4

126.1 122.8

106.5

119.5

108.6

116.2

125.8

112.9 109.5

109.3

106.2 102.9 99.6

129.6 130.4

92.9

105.2

89.6 86.3 83.0

74.4

79.7

48.8

76.3 73.0

20.2

69.7

93.0 82.0

65.1 40.3

63.1 59.7

125.8

112.9

66.4

76.1

57.7 30.6

56.4

116.5

130.4

124.1

96.3

74.1 97.5

120.8 129.1

53.1

123.5 115.7

34.9

49.8 46.5

MAX= 133.0 15.7

103.8 108.6 107.9

107.1 88.0

100.1 83.6 60.1 13.4

79.8 60.9 43.6

36.5 33.2

11.2

29.9 26.6

119.3

108.8 117.4

112.5 95.2

19.9

75.2 95.8

67.9 15.2

16.6

131.0 126.7

126.0 109.0

13.3

135.4 131.5

107.039.3 116.2

128.0

38.2

23.2

Maximum Stresses

-5.00

127.6 116.8 96.6

122.9 100.9

43.2 39.8

10.6 93.1

104.3

115.7

119.8

63.2

5.60 65.6

124.7

118.0

111.2 107.9

37.3 128.2 114.6

Y

ZX

124.6

104.5

-10.00

101.1 97.8

91.0 87.6

128.6

61.1

80.9 77.5

32.0

74.2 70.8

64.1 31.7

1.95

67.4

Stabelemente , Vergleichsspannung, Bemessungsfall 100, Material 1 C 24 Cl.2 (EN 1995)

10.00

, 1 cm im Raum = 373.4 MPa (Max=133.0)

5.00

0.00

50.6

m

126.1 115.0

82.3

98.3

61.5

83.1

39.1

58.2

31.9

87.7

99.3

82.6 -5.00

130.1 98.0 132.3 106.8 125.3 124.2

107.0 94.8

118.0 133.6 106.9 129.3

75.9 54.0 29.2

3.26

59.0

99.6

129.4

100.6

9.13

53.9

15.00

56.4

20.6

60.7 57.3

20.00

77.6

64.0

-15.00

72.4

118.0 129.0

129.2

117.7

93.8

84.3

96.7

128.1 127.1 131.3 133.6 133.0 132.7

120.0

79.1

94.4

115.9 120.7

6.6

0.2

123.4

114.6

50.0

9.9

3.3

121.4113.9 49.0

121.3

99.6

0.00

124.9

128.1

88.1 71.1

47.2

112.5 101.6

126.8

43.8

M 1 : 107

50.1

40.4

X * 0.833 Y * 0.987 Z * 0.578

37.1

23.2

33.7 30.3

92.3 67.1 97.3 31.6

23.6

Max sig = 133.0 MPa < sig,d= 0,6*240 = 144 MPa

20.2

4.06

16.9 13.5

94.1 41.8 41.6 127.7 MAX= 135.4 119.4

-10.00

121.0

58.9

27.0

106.234.6

114.6

129.4 132.7 98.7

62.2 24.4

-15.00

10.1 6.7 3.4 0.5

Structural Engineering - Maximum stresses and deflections

Y

ZX

20.00

15.00

Stabelemente , Vergleichsspannung, Bemessungsfall 100, Material 1 C 24 Cl.2 (EN 1995)

Max sig = 135.4 MPa < sig,d= 0,6*240 = 144 MPa

10.00

, 1 cm im Raum = 373.4 MPa (Max=135.4)

5.00

0.00

m

M 1 : 108 X * 0.833 Y * 0.987 Z * 0.578

Testing

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Faraday Pavilion Roskilde Festival 2012

R0

P

R1

1.15

R2

2.13 3.05

0.83 R17

3.9

1.82

R3

4.64

2.77 R16

5.25

3.64

R4

5.67

4.42 R15

6.03

5.07 6.18

5.59

6.08

5.81

6.15 6.13

5.95

R5

5.38 4.8

5.91 R14

4.09

5.53

Design Documentation All design documentation was derived from the 3D model. An underlying circular geometry embedded into the form-finding process provided the logic by which the site was surveyed and set-out points for the footings identified. Simple spreadsheets were then used to set the correct overall length of each element and to position the connection points along them. Footings and element were tagged with a laser-cut identification tag, which made the erection process straightforward. The sequence of erection matched that of the simulations - all radial elements were firstly raised, and then connected by transverse elements. The seating elements were pre-milled and assembled on site.

3.27

5

R13

2.46

4.33 1.37

3.54

R12

0.35

2.65 1.68 R11

A - Inner - Radial

R6

R10

0.69 R9

P

R8

R7

Radial Pole Number 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

Radial Pole Length 13,662 12,675 12,118 11,823 11,763 11,833 11,949 12,166 12,513 13,283 12,912 12,371 12,126 11,998 12,001 12,122 12,727 13,728 14,537 12,404 11,276 11,607 13,473 15,372 15,232 13,308 12,164 12,153 12,412 12,499 12,187 12,162 12,45 13,937 11,906 11,732 11,608 11,521 11,575 11,818 12,341 13,497 14,457 12,831 12,222 12,083 12,152 12,559 13,08 12,398 12,079

Distance of connector from centre 4.333, 7.246, 9.521, 0.228, 4.636, 7.62, 1.604, 5.594, 10.584, 0.243, 3.54, 3.741, 7.226, 7.551, 1.191, 1.918, 4.93, 6.125, 9.736, 10.579, 2.516, 4.218, 7.609, 8.682, 0.405, 1.668, 5.088, 6.723, 9.294, 11.802, 2.669, 4.301, 6.973, 9.577, 0.468, 5.371, 6.898, 4.399, 9.249, 4.337, 7.05, 0.583, 4.912, 5.607, 11.292, 2.577, 3.085, 6.615, 7.994, 1.474, 3.093, 5.685, 8.827, 0.38, 0.85, 4.623, 5.554, 9.661, 11.441, 2.616, 6.899, 8.401, 0.549, 5.232, 4.546, 6.997, 8.734, 8.9, 10.094, 10.183, 10.918, 0.579, 3.018, 11.124, 2.662, 6.857, 3.274, 6.589, 0.707, 7.078, 11.893, 9.22, 10.269, 10.894, 8.75, 10.06, 10.468, 0.701, 1.295, 2.412, 11.502, 2.325, 5.26, 6.016, 1.622, 4.446, 6.853, 9.698, 3.788, 7.201, 4.071, 8.714, 1.393, 3.072, 6.829, 9.897, 5.377, 1.351, 3.41, 10.684, 7.738, 9.024, 9.979, 0.011, 2.612, 3.797, 8.133, 8.82, 0.702, 1.3, 5.705, 6.117, 10.567, 3.298, 8.138, 8.437, 0.779, 1.343, 5.54, 5.794, 9.933, 10.92, 0.089, 2.411, 3.366, 7.901, 8.223, 1.281, 4.501, 6.695, 10.471, 0.132, 5.478, 6.651, 5.011, 7.632, 8.917, 9.661, 4.38, 8.129, 9.438, 10.662, 0.86, 2.568, 5.86, 12.501, 3.919, 8.354, 9.934, 0.533, 4.475, 7.773, 10.761, 1.167, 4.962, 6.469, 10.987, 4.47, 8.645, 5.673, 9.341, 0.261, 6.314, 6.952, 2.045, 4.405, 7.614, 10.105,

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Faraday Pavilion Roskilde Festival 2012

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Faraday Pavilion Roskilde Festival 2012

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Faraday Pavilion Roskilde Festival 2012

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Faraday Pavilion Roskilde Festival 2012

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Faraday Pavilion Roskilde Festival 2012

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Faraday Pavilion Roskilde Festival 2012

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Faraday Pavilion Roskilde Festival 2012

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