MArchDFM_Portfolio // Papandreou Marielena by Marielena Papandreou

Hello World!

This booklet is divided in two sections. Section A tells the story of the vanishing relationship between a robot and a pine tree, while section B is an adventure tale of four girls that decided to mess around with concrete. Both stories are based on true events that took place at the Here East Campus of UCL. They are connected by a theme which is related to the the passion of a young architect to exploit the available digital technologies in order to learn, create and destroy!

Enjoy!

01 02 03 intro

timber

connections

structure

04 co Nt 05 06 eN planning system

h a r d wa re

evaluation

08 07 ts a s se m b ly

outlook

0.86 m 0.40 m

2.60 m

1.20 m

5.00 m

DataTree <Line> perpLineGroups = new DataTree <Line> (); List <Line> tempPerpLineList = new List <Line> (); DataTree <Line> lineGroups = new DataTree <Line> (); List <Line> tempLineList = new List <Line> (); for (int j = 0 ; j < iMidPt.Count ; j++) { for (int i = 0 ; i < iAuxLine.Count ; i++) { Point3d startPt = new Point3d(iAuxLine[i].PointAt(0)); if (startPt == iMidPt[j]) { tempPerpLineList.Add(iAuxLine[i]); tempLineList.Add(iInteriorEdge[i]); if (tempPerpLineList.Count > 1) { GH_Path pth = new GH_Path (j); perpLineGroups.Add(tempPerpLineList[0], pth); perpLineGroups.Add(tempPerpLineList[1], pth); lineGroups.Add(tempLineList[0], pth); lineGroups.Add(tempLineList[1], pth); tempPerpLineList.Clear(); tempLineList.Clear(); } } } } oPerpLines = perpLineGroups; oPairs = lineGroups;

Thesis Project C o l l a b o r at o r s : V i c t o r L i n

iNTRODucTioN

[ co n tex t ] [ st a t e - o f - t h e- a r t ] [ aim ] [ m e t ho d o lo g y ]

MOTIVAT IO N & C O N T E X T mass customization workfLows The established ways of design and production are challenged by tailor-made computational and fabrication tools. The key to innovation in the field of manufacturing is a function of knowledge on materiality and production process, talent to vision and skill to address the latest techniques and technologies. Digital solutions for interfacing seem to proliferate, yet we are still far from an established general platform that allows an informed collaboration especially in the field of fabrication. While digital fabrication has empowered the creative employment of mass customization across many design disciplines, the actual implementation of these methods and technologies bears a lot of unresolved questions. These vary from technical matters, like the selection of appropriate tools and the potential interfacing between them, over matters of management of manufacturing and assembly,.

photos: 1. ICD/ITKE Research Pavilion 2011 University of Stuttgart 2. Parametric Wood Royal Danish Academy of Fine Arts 3. Articulated Timber Ground University of Melbourne

Is it possible for an autonomous robotic cell to accomplish a set of established carpentry tasks in a seamless digital workflow such as:

- identifying stock material - processing it in a known manner - placing it into a specific position

Structure + Methodology

CASE STUDY THE BRIDGE

st ruct

ur al

c onne

ct io ns

se lf -l oc kin g t im be r jo in ts

02 d i re c t l i n k t o st ruc t u ra l analy s i s

ge ne ral

ge om etry

(c ontrol c ur ves, me sh t ri angu lati on )

ge om etri c detailin g

(i nterse ct io n pl ane s b etween each t ri an gl e & each b ea m)

ge ne rate f abrica ti on d ata

(t arget gr ip pi ng p la ne s, m illi ng p la ne s pl ac em ent pl an es )

robot co ntrol

(rob ot & t oo l d ata, proc ed ure lo op )

1 The investigation and review of timber connection techniques 2 The design and performance of the overall structure 3 The establishment of a deterministic planning system 4 The analysis of the tooling and techniques that were adopted 5 The examination and evaluation of the fabrication process.

state of IBOIS , EPFL Integrated Mechanical Attachment for Structural Timber Panels In the ongoing production lines of timber elements, we usually encounter three disrupted interfaces. The one involves Computer Aided Design (CAD) platforms, the other is related to Computer Aided Manufacturing (CAM) software and last but not least the manual labourers complete the construction process. CNC machinery is used predominantly for the precise material processing and we could claim that its limited flexibility handicaps this method of production.

Gramazio Kohler Research, ETH Zurich & ERNE AG Holzbau Spatial Timber Assemblies There have been several research studies which focus on the assembly of timber elements in space rather than just processing of single parts. Gramazio Kohler Research at the ETH Zurich has been investigating during the past years the possibilities of large scale robotic assembly. However, in almost all the papers published complete automation is never achieved since the human factor is always intervening to fix the different elements in place.

t he aRt

t i m B E R c o N N E c t i o n s

[ bo t t o m - u p d es i g n ] [ se l f -loc k i n g jo i n t s ] [ ra c k jo i n t ] [ dove t a i l jo i n t ]

BOTTOM-UP DESIGN

A bottom-up design approach is adopted because it assists the process of working with both the material itself and the digital fabrication techniques. The study of wood joinery happened with both advanced computational methods and physical 1.1 prototypes. A bridge was chosen as a medium to demonstrate the aforementioned intentions. The general form is based on the concept of a triangulated truss which is created by the conjunction of relatively short timber beams.

rack joints

self-locking lap joints

joi nt de sign parame te rs : / ability to self align / fulfil the structural requirements to transfer loads / facilitate machining / have only one degree of freedom

SELF-LOCKING JOINTS

The connection between the beams of the triangle is based on the half-lap joint. However, instead of straight cuts the proposed geometry has a hook-like shape which blocks further rotation when it reaches the desired position.

RACK JOINTS

The connection between the different triangles happens at the long side of the beam. This joint is based on the finger joints system which originally are a planar pair of opposite shapes that have 3 degrees of freedom. We expanded this planar design in a three dimensional set of complimentary geometries in order to reduce the degrees of freedom to only 1. The trapezoidal shape of the ‘rack’s fingers’ facilitates self-aligning.

DOVETAIL The rack joints demonstrate high resistance to shear forces parallel to the edge of the beam and compressive forces perpendicular to the beam. Yet bending moments are also transmitted from one beam to another.

Xj+2 Xj+1

Ttop

Tbottom v

We had to modify the rack joint in order to correspond to the variable angles between the triangles and at the same time to tackle the structural incapacities of the finger joints.

The connection is designed parametrically based on the traditional wood joinery technique known as dovetail. The dovetail joints apart from being capable of resisting shear and compressive forces like the rack joints, they can also withstand bending moments as well as traction forces that are not necessarily perpendicular to the beam.

stRucturE

[ bridg e ] [ st ru c t u ra l a n a l y s i s ] [ de sig n va r i a t i o n s ] [ di ve rse a p p l i c a t i o n s ]

bRIDGE z x

OM ET

RIC

length width curvature height of top curves

variab le s

height of bottom curve

Extract Information for Structural Analysis & Fabrication

[Triangles, Naked Edges, interior Edges, Supports ]

Generate Delaunay Mesh

[constructs a mesh based on the Delaynay Triangulation Method]

Divide curves in variable lengths

[cull points that the distance between them is smaller than 500 mm]

Generate control curves

[variable width & height of truss ]

DE FIN

ITIO

Asign general measurements

[length, height, curvature ]

STRUCTURAL ANALYSIS

An irregular triangulated mesh was analysed in Karamba software. The mechanical behaviour of the arch bridge along with the compression strength of the material permit a longer span way more effectively than in a flat bridge.

utilization

3mm max displacement

tens io n

comp ress io n

The mechanical behaviour of the arch bridge along with the compression strength of the material permit a longer span way more effectively than in a flat bridge.

variations

Design

triangle_1 ver tice_A ver tice_B ver tice_C

triangle_2 ver tice_A ver tice_B ver tice_C

triangle_3 ver tice_A ver tice_B ver tice_C

... triangle_n ver tice_A ver tice_B ver tice_C

V1b=V2a

V1a T1

V1c=V2b

V2c

plaNNiNG s

[ c o m put a t i o n a l wo r k f low ] [ c u st o m t o o l s ] [ da t a sor t i n g ]

COMPUTATIONAL PROTOCOL

The realization of a rigorous software solution for the production of design and fabrication data is one main difficulty of the project. More specifically a digital model, which can accommodate all the complex relationships of its contained elements, has to be orchestrated properly in order to deliver valid information for every step of the design and construction of the case study. Custom computational tools were designed in order to handle and archive the multiplicity of properties and operations that describe each beam. In the next page the three main data editing actions are described, which were necessary for the generation of the machining toolpaths per part.

DATA STRUCTURE EDITING

data structure for

self-locking joints

dovetail joints

toolpath per beam

tria ngle_1

comm onEdge_1 comm onEdge_2 comm onEdge_3 ... comm onEdge_n

be am_A beam_C

tria ngle_2

be am_A be am_B be am_C beam_C

te mpBeam_A te mpBeam_B

tria ngle_3

te mpBeam_A te mpBeam_B

be am_A be am_B be am_C beam_C

te mpBeam_A te mpBeam_B

... tri angl e_n

...

be am_A te mpBeam_A te mpBeam_B

beam_C

data tree (bridge output-triples)

List + data tree (with corresponding

data tree (from pairs back to triples)

(corresponding paths with initial data tree)

BEAM A

BEAM C

data sorting for fabrication

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

BEAM B

ROBOTIC CELL - in du strial rob ot K UKA KR 60 - rotary t ab le

- ma terial feedi ng s tati on

- pa rallel p ne um at ic g ri pp ers - sp in dl e

- cu stom d es igne d worktabl e - storag e sh el ves

- optitr ac k ca me ras

- retro- refl ec ti ve s ph eres

haRDWARe

[ ro bo t i c s et u p ] [ c e ll co m p o n en t s ] [ c a l ibra t i o n s t ra t eg i es ]

tool- to- paR t

pa Rt -to- tool

Two different robotic setups have been tested namely tool-to-part and part-totool. Their difference lies in where the material billet is placed with regard to the robotic arm.

ce l l c o m p o n e n t s

Ø8

10 3

Ø8

69.28 R29

125

10 3

R29

125

22.5

69.28

111.72

22.5 111.72

59.5

Tracking Marker Ø 12.7

59.5

Tracking Marker Ø 12.7

Ø4

Ø 19 Ø4 150

Ø 16 Ø 19

45˚

70.7

70.7 Ø 16

Ø4

8 19.4

Ø 6.8 M8 Tapped

Ø4

200

100

Ø 16

Ø4

150

Ø 16

70.7

100

Ø 16

.2 69

200

Ø 19

45˚

70.7

Ø 6.8 M8 Tapped

Ø 16

39 7

1.7

Ø 19

1.7

al umi num plate for the rotary table with spindle body

m o t i o n c a p t u r e s y s t em w i t h i n t h e w o r kc ell [c a m er a s + r et r o r eflec t i v e m a r k er s ]

The optical capture system called Optitrack uses ten cameras and a set of retroreflective markers. The cameras are placed in the perimeter of the robotic cell in a way that each of them have a vantage viewpoint. The cameras capture multiple 2D pictures and rebuild the information into 3D coordinates through Motive software. Custom hardware was designed and made that features holes in specific positions for tracker locations for the calibration of the work cell.

106.42

Tracking Marker

106.421

160

106

Ø4 30

Ø8

Ø8 Ø12 10

93.5

Ø8 7.5 20

20 66.42

126.294

500

M8 34.64

14.34

Ø10

41.15

57.15

100

Ø 6.8 M8 Tapped

12.57

66.4

60 B

E E

Ø 4.2 Ø10.2 x 90˚

14.34

50.58

Ø10

7.5

20 E

Ø8 Ø12 10

E D

1500

1.5m alum inu m r a i l w i t h p n eu m at i c g r i p p er s

34.64 B

R15

5.62

Ø4

Tracking Marker

R15

Ø8

27.86

20 E

16.93 D

93.5

126.294

Ø8 7.5

Tracking Marker

Ø4 Ø8

12.57

Tracking Marker

27.86

Optitrackâ&#x20AC;&#x2122;s ground plane with 3 retro-reflective

The same dimensions of the calibration

markers. The origin within Motive is set to

triangle was used to set location of 3

wherever this device is placed in space.

trackers when creating the rotary tableâ&#x20AC;&#x2122;s aluminium plate.

aluminium plate with integrated marker's holes

spindle

cutter

bolts/washers

retro-reflective markers

tool changer

T nuts

pneumatic actuator

waterjet cut aluminium parts for the grippers' jaws

3mm mismatch due to calibration error

Four-Point Calibration with the long spike. Robot accuracy depends on human precision

c a l ib r at io n

The calibration procedure of the robot is a time consuming process and we could claim that the results are often fallible because this method is highly dependent on human precision. This is one of the primal reasons why industrial robots fail to achieve absolute positioning accuracy. In search for a quicker and utterly reliable method, we decided to use Optitrack for the adequate set up of the relationships between the distinct components within our workcell.

robot c a li b r at i o n u s i n g o p t i t r ac k

Robot and rotary table calibration using trackers in a circular motion to get the 2 centre planes

hardwa r e c a li b r at i o n u s i n g o p t i t r ac k

We will calibrate all our tooling based on the tracker positions that were integrated in the design of our hardware

lo n g spike-sh o r t sp i ke TC P c a l i b ra t i o n u s i n g c a p t u red p o i n t s

m ate r i a l t r ac k i n g

In terms of material variabilities, the timber beams can present dimensional inconsistencies in comparison with the digital model. These must be identified prior to any fabrication action and evaluated with regard to tolerances of the design system.

Wa r pin g eva l u at i o n a c c o rd i n g t o c a p t u red d a t a

3d pr in ted j ig w ith retro -re f lec t i ve ma r ke r s t o d e t ec t s t o c k ma t e r i a l

machiNiNg R

[ t o o l p a t h s t ra t eg i es ] [ re so n a n c e & f i n i s h i ng ] [ t o le ra n c e & f i t t i n g ] [ sh if ted jo i n t g eo me tries ] [ m a t e r i a l wa r p i n g ]

t o o l pat h s t r at g ie s slotting

1. p ath : offset surfaces result: sharp corners

flank milling

2. p ath : chamfered control polylines result: chamfered exterior/ fillet interior corners

3. p ath : zoning increased to 6 mm result: smooth curve

Different types of toolpath strategies that were initially tested and their geometric results

Breakouts of the wood when the cutter is exiting the material depend on speed, feed rate, grain direction, type of wood, cutter geometry.

RESONANCE & FINISHING

Different surface finish due to cutter’s geometry, speed, feed rate.

Chatter at the edge due to robot’s configuration and material’s cantilevering.

Surface deviations along the edge of the beam due to vibrations.

T O LE RA NCE & F ITTING

Opti calibration / 0.6 mm tolerance / single pass

4pt calibration / 0.8 mm tolerance / double pass

Opti calibration + comp. robot / 1.2 mm tolerance / double pass

4pt calibration / 1 mm tolerance / double pass

Opti calibration + comp. tracked data / 1.2 mm tol / double pass

4pt calibration / 0.9mm tolerance / double pass

front view / Part-to-tool setup

back view / Part-to-tool setup

shif te d j o in t g e o me t r y

Rotation around A6

Rotation around A5

Rotation around E1

ac c u mu l ate d cal ibration e rror : / Tool-to-Part TCP definition / rotary table calibration / multiple rotations for milling

r es u lt : / correct geometry / wrong relationship between joints

Alternative milling positions with tool to part setup to reduce uncertainties

mat erial warping

Another cause of geometrical inconsistences is the material deviations of the timber beams in comparison with the digital model. After we scanned six beams we realised that there were considerable differneces between the anticipated size and the real measurements.

a s s E m B ly

[ a ssemb l y s eq u en c e ] [ wo r k i n p ro g res s ]

ASSEMBLY

SEQUENCE

wo R K i

PRogRess 63

08 l

j o int FEA

After

building

the

whole

structure we realised that the weakest joints are the ones at the nodes. Localised structural conditions should be analysed and improved.

feed bac k base d proces s es \

Full

automation

implies the application of

feedback-based

processes in order to manage the un-modelled properties material parts.

of or

stock

assembly

Robotic asse mbly

\ The motion planning to carry out both cutting and assembly tasks has to be carefully coordinated to avoid global collisions, robot singularities and axis rotational limits.

Tolerance Balance for Manufacturing, Assembly, Structural capacity \ Finding the right tolerance balance between the required structural performance and movement flexibility for the assembly of tight-fitting dovetail joints \ Cross section optimization is necessary to reduce material redundancies

01 fo r c e i n fo r m e d a r c h i t e c t u r e

02 component design [TERM1]

03 formwork studies [term 2]

Heinz Islerâ&#x20AC;&#x2122;s examples of the endless forms possible for shells, from the 1959 IASS conference (Isler, 1960)

F o R C E iNfoRmed a R c h i t E c t u r e

A BRIEF INTRODUCTION

There have been numerous attempts within architectonic research to blend engineering and architecture. How could statics be nested into a shape, structural calculation enrich creativity or technical thinking guide and define the synthetic process and conformation of a building? Many methods have been developed for these questions to be answered. From experimental form-finding to digital simulation and structural optimization, architects and engineers have tried merging their synthetic abilities and technical knowledge. In the work presented below, both in Term 1 and Term 2, I investigate how the implementation of digital tools can give us information about the force flow of a structure to obtain its efficient shape. An attempt is made to explore the virtue of structure as a primary component of architectonic composition, by focusing on the methods of form finding and digital simulation. The conception of structural properties from the early stages of the design constitutes a key element of the synthetic process. As the main material of the RC101 cluster brief is concrete we will start in Term 1 by studying compression only structures. What does funicular mean and how boundaries and supports affect the shape of a volume? How does concrete behave and how carefully a mold should be designed and treated? In Term 2, we will continue with a deeper investigation of formwork systems. We will conduct digital simulations to create systems that work in tension and are able to support large concrete volumes with the minimun material arranged in such way that it represents its stronger state. Last but not least, we will try not only to be efficient in terms of structure but also on fabrication methods. Material cost and waste, on site labour, transportation issues, accuracy, assembly and cast time are only a few of the parameters that we took into consideration for the realization of these projects.

Parametric FEM Solutions for meshing complex geometries. The new central station for the Stuttgart 21 infrastructure project by Ingehoven Architects with Frei Otto features complex double curved concrete geometries.

Building in concrete with a knitted stay-in-place formwork: Prototype of a concrete shell bridge / Popescu M., Reiter L., Liew A., Van Mele T., Flatt R.J. and Block P - ETH Zurich

compoNENt D

[ g e t t i n g fa mi l i a r w i t h concrete ] [ de sig n res ea rc h ] [ f o rm - f i n d i n g w i t h R V ] [ t ex t ure ] [ f a bri c a t i o n s c en a r i o s]

GETTING FAMILIAR WITH CONCRETE

C O MPONE NT DE SIGN Our first task was to design a component for our first casting workshop. They design would be a simple origami form. My intention was to make and object, which when multiplied, can form a wall that could either carry vegetation or serve as a bookcase or in general provide variations of lighting.

origami exploration

cardboard test model

references: (1) Design robotics group, Harvard GSD //(2) ceramic design project by Linda Zhang and Jenny Hong // (3) Archi Union Architects, AU Office and Exhibition Space

component aggregation

MOLD DE SIGN I chose plywood for the material of the mold. It was easy to assemble and to demold. The main problem was that because wood is opaque there is no way to guarantee that the concrete has flown everywhere within the mold, especially in such a complex geometry that I chose to cast in. We can see in the resultant component that there is discontinuity of the material in some corners. Moreover the surface has a nice rough finishing but at the same time it is too brittle.

CASTING WORKSHOP In our first casting workshop we used a mix of one part fast-dry cement, 3 parts sand and water. Below are some pictures of the process as well as the result of the casted object.

DESIGN RESEARCH

FR EEFORM VS. F ORM F OUND In search of a general form that would be comprised by smaller concrete components, I conducted a structural analysis to understand the structural behavior of shells. I used Karamba software for the calculation and visualization of the deflections under gravity loads of two given models; a freeform surface and a form-found shell. The material I used for the simulation was concrete C35/45

freeform surface

rhinoVault surface

Displacement values (a) and deformed mesh in plan (b) and side view (c)

SET T ING CONSTRAINTS - THE H O U S E C O N C E P T To delimit the design space of my digital experiments I realised I have to put some constraints in my simulations. Can we design a vault structure using rhinoVault, where the form, apart from structural, produces a functional efficiency as well?

support points could create more private areas where necessary

computational workflow diagram

perspective

bird-eye view

form graph

force graph

84 kitchen

patio

bed

drooms

FORM FINDING WITH RV

base surface

form diagram

form graph

force graph

EVALUATION OF THE RE SULTS After numerous trials with Rhino Vault I finally reached a shape that would serve my housing goals. As is indicated in the section diagram, in the big open space of the front side, the living areas are located and they are directly related to the patio. The back side of the patioâ&#x20AC;&#x2122;s perimeter is lowered to the ground to provide privacy to the sleeping areas. On the right side the vault, support points to specific places create a solid front where the bathroom would be located.

85 bathroom

living room

MES H OUTPUT An attempt is made below to apply a component (a) and a brick pattern (b) on the mesh geometry. The resultant mesh of rhino vault is not organised in such a way that I can directly use it for further design of my shell structure. Further manipulation of my digital model is necessary to organise my geometry in such a way that I can continue my parametric workflow. How can we extract useful geometries from the resultant shape?

By using directly the mesh output of rV for further design of my shell I get a random division & orientation of bricks

CONVE RT TO SURFACE Below there is a definition of converting the rV output to a valid surface that we can analyse and proceed to further design & construction solutions. The idea behind this grasshopper definition to get a surface out of the mesh is inspired by the falsework used to build such structures. First we create a dense planar grid (a), then we project it to the mesh (b) and finally we use this 3d set of curves to create a surface. On the last figure (c) we can see the 3d shape of the lofted planar and projected lines.

FURTHER DESIGN OF THE SHELL STRUCTURE

TEXTURE Now that we have obtained a valid 3d geometry of our compression only vault we can proceed to applying construction elements to its surface. A rough finishing is proposed for the interior of the shell in order to fix acoustical problems of such curved space.

ACOUSTIC TILES REFERENCES (1) ‘sleath’ by 3d wall panels, (2) One brick type rotated into 6 different position by Klink and Petersen Tegl, (3) wooden decorative wall, (4) LAINE, acoustical panel by Anne Kyyrö Quinn, (5) acoustic tiles in the Elbphilharmonie Hamburg by Herzog & de Meuron, (6) Scale by Filz Felt, (7) 3d pixel by Beau

COMPONE NT DE SIGN Considering the initial goal of this term I decide to break the surface into individual interlocking components. When they are placed together they create the shell structure.

vertical & horizontal contours to split the surface

component boundaries

FABRICATION SCENARIOS

POLYUR E T H A N E F OA M MO L D S Two 3d models were prepared for CNC milling. One contained 3 components and the other a scaled model of the whole shell structure.

P R EPARATION OF THE MOL D There are certain important steps to be taken into consideration for the milling process and preparation of the mold out of Polyurethane Foam. First, measuring the block is of high importance. As we can see in the second picture there is a big difference between each side of the foam block volume. This extra material needs to be removed in order to achieve high accuracy. After the geometry has been produced, the surface that we will cast within needs to be sealed as is shown in the last picture. The use of PVA glue was not the best choice since its is a water disolved material. As a result demolding was quite a challange for both models. Since the scaled model of the shell was really thin, it broke while I was removing it the foam.

fixed tolerances for the tiles to interlock

two-part mold digital model

CONCRE TE RE SULTS A fibre reinforced premix with no aggregates was used this time for casting. The mix was fluid enough to reach all the parts of the complex geometry produced. The material result is a nice matte texture which has not changed through time.

STEP WISE CONSTRUCTION OF T H E S H E L L If every concrete component is unique then milling is not the most efficient way of production. So another way of construction in layers is proposed. The mold is comprised by a steel formwork for the interior side of the building and the insulation for the exterior side. The distance between them is controlled by spacers. The process is described below:

1. we fix the steel formwork and insulation material 2. we pour the concrete 3. once the concrete is dry, we remove the formwork and place it on top of the compacted concrete 4. we pour the second batch of concrete 5. once the construction is finished, the exterior surface is sprayed with concrete

sprayed concrete insulation

steel formwork

poured concrete

C o l l a b o r at o r s : G a r z a C r i s t i n a , O u Ya n g N i e n , U z i e ly A n at

foRmwoRk s

[ co m p a re & c o n t ra s t ] [ g rids h el l p ro t o t y p e ] [ ca ble - n et i n t en s i o n ] [ ca st i n g ex p er i men t ] [ h o u s e d es i g n ]

compare Toyo Ito & Associate s / C r e m at o r iu m in K a k a mig a h a r a The main concept of the design and optimization process of this building is a smooth, hill-like roof. The algorithm used to improve its structural performace iteratively seeks for possible design alternatives, with respect to the supports, the perimeter of the roof and a structural principle. This building exemplifies the optimization process as a means of design exploration, in a way that priority is given to the form rather than mechanical, economical or environmental properties. Same logic was applied on its fabrication method. Large pieces of wood were bent or milled with CNC on specific shapes to create this rigid and unique formwork. The cost, labor and waste of material behind the creation of this temporary structure was significant.

De sign & Co n s t r u c t io n R e f e r e n c e s In the examples presented in this chapter we look at two completely different projects both in terms of design approach and construction methods. These two projects follow opposite principles but yet have a quite similar geometrical expression.

contrast Block re se arch gr o u p - E T H Z u r ic h / N E S T H iLo The roof of HiLo is a thin shell structure to be constructed using a prestressed, cable-net and fabric formwork. The shape of the roof is largely determined by the geometry of its boundary edges as well as its supports. Its tickness is variable and reduced in accordance with a load simulation that was applied in the resultant form-found geometry. The reusable and lightweight mixed cable-net and fabric formwork system that was used for the construction of this project allows the creation of doubly curved thin shell structures without the typically associated high labour and resource investments. The project aims to reduce construction cost of shell designs. It is easily transported and there is no need for scaffolding or temporary foundations.

Ke y D ir e c t io n s Since concrete is relatively cheap, the production of the formwork and scaffolding in most concrete buildings is the biggest expense in terms of material price, transportation and labor. The Crematoriumâ&#x20AC;&#x2122;s construction methods revealed to me a great challenge that needs to be addressed and HiLoâ&#x20AC;&#x2122;s roof a big inspiration in terms of efficient, weight, reusability and adaptability of formwork solutions.

104

GRIDSHELL PROTOTYPE

GE N E R A L D E F IN IT IO N keeping edge lengths of a quad mesh equal

This aim of this research is to create an adaptable formwork system with standarized components that could take any shape and then be reused in another project. To achieve this we try to analyse a solid shape to a mesh with equal edge lengths. We developed a scrip that starts from a flat mesh grid and then

it is draped over a

solid shape. The result is a mesh that describes the initial solid shape with node to node distance fixed but variable angles between the edges.

105

The logic behind the digital simulation is explained below: Set N to 1 to start the simulation. Raise to 10 to increase the strength constraint and

[raise 10 to the power of N]

length lines

strength

gravity force

nodes

[smaller integer for strength input > curves deform] [larger integer for strength input > curves try to

solid geometry

solver

1<N<10

equal length curves on solid geometry

maintain curves original length after the simulation runs.

maintain their original length]

HY P E R B O L IC C O R E applying the concept to a pre-defined form The design brief of this term was about the creation of a structure that would be defined by a hyberbolic column. We produced a geometry in which continuity is maintained from the ruled surface of the hyperbolic paraboloid to the flat ceiling. We choose to run our drape simulation definition to the intermediate freeform part of the composition.

flat ceiling

freeform part

ruled surface

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UN IV E R S A L J O IN T standardizing the components We designed a universal joint that could accommodate almost every angle in plan and section. This joint would have slots to receive equal length steel pipes. For our 1.10 model its was not feasible to create such components so we 3d printed all 110 unique joints to assemble the mesh. The pipes were created out of copper rods.

section

plan

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SHUTT E R IN G M AT E R IA L S potential options to seal the gridshell The formwork system could be shuttered with various materials in order to act as a mold. The following diagrams show some material proposals such as textile and foam that could be combined with the steel gridshell. We will investigate both how textile patterns can be produced and how foam blocks can be shaped in accordance with the desirable geometry.

foam foam

concrete

textile textile

steel gridshell steel gridshell

foam foam

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CABLE-NET IN TENSION

ME T H O D IMP R OV E M E N T introduction of a stronger technique that can support concreteâ&#x20AC;&#x2122;s heavy loads After assembling the rectangular gridshell of the mixed system of rods and joints that is presented in the previous pages we realised that it was rather weak and likely unable to support the weight of the concrete. Consequently, we started searching for a stronger solution that would serve our goals. By physicaly and digitally constructing a system that works in tension we understood that a cheap, lightweight and resuable material such as steel wire when prestressed and fixed properly can generate a variety of geometries and carry significantly heavy loads. We created a parametric definition that used a radial rather than a rectangular grid to facilitate fabrication.

Test model with cotton string to understand how a mesh in tension works

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DIG ITA L D E F IN IT IO N parametric definition of the tension simulation & the construction process

boundary conditions

radial division

top anchor points

creating the mesh

generating the base for a

base of the column & roof

radial grid

intersection of the base division with the roof perimeter

producing a surface by connecting top & bottom anchor points

geometric simplification for fabrication

construction elements

perimeter

verctical force to the nodes applying inverse gravity force to the points of the mesh

mesh in tension setting the rest length of the lines to be smaller than the initial length

orienting consctruction details to the resultant geometry

equalizing the different lengths of the resultant geometry

VARIAT IO N S O F T H E S Y S T E M applying the concept to an off-centred geometry or a 2-columns composition

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D E TA IL S The system we propose is covered with a waterproof textile. Foam blocks which will be the insulation of the building are placed in a certain distance from the textile. These two materials form the mold where the concrete will be poured. Below are some details that show how the system could be built in real scale.

2. textile fixture

1. insulation foam block

steel pipes wires foam block

3. joint detail

textile textile fixture

4. tension archor

steel pipes wires steel joint

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steel beam tension anchor bolts

Construct io n p r o c e s s o f t h e me s h

Initial sy s t e m b e f o r e s t r e t c h e d

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Se wing pro c e s s o f t h e P V C T e x t il e

Te nsione d state af te r a l l t h e c o m p o n e n t s a r e p u l l e d

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HOTWIRE FOAM CUTTING

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10.

11.

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S C A L E 1 .1 0 We out face

used of

KUKA

robot

polysterene

and

split

foam. into

hot

We 4

wire

cut

simplified pieces

the

for

second

part

geometry

into

our

first

casting

our

mold

ruled

sur-

experiment.

After we cut the pieces we glued them and sealed them with latex in order to be waterproof. Then we covered the surface with fibreglass tape and placed on top a steel mesh for the reinforcement of the concrete. Bellow is the toolpath the robot will follow to cut the pieces and on the next page some pictures of the final result of the foam pieces glued together.

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1. Hot wire cut foam blocks 2. Concrete 3. Hot wire cut foam blocks 4. Cable wires

6. 7. Nut 8. Tread rod

5. Steel pipes

9. Foam piece

6. Panels join to connect the three layers together.

10. Metal plate

Section of the erected system

Physical model of the insulation panels in tension / scale 1.50

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INSUL ATING CO N C R E T E F OA M ( IC F ) PA N E L S details of the formwork system Even though in our physical model we will test a combination of PVC textile and foam as a mold, we briefly investigate the possibility of having on both sides foam. The same logic of a system that works in tension applies here as well. Once on site the wires that run inside the foam blocks are stretched giving the final shape of the volume. There are spacers that assure that the foam blocks will stay in a certain distance.

4. 5. 4. 5.

1. Top layer: Foam 6.

4. 5. 6.

2. Middle layer: Concrete 6.

2. Middle layer: Concrete 1. Top layer: Foam

6. 4. 5.

1. Top layer: Foam

3. Bottom layer: Foam

2. Middle layer: Concrete

2. Concrete

3. Bottom layer: Foam

3. Hot wire cut foam blocks 4. Cable wires

5. Steel pipes

6. Panels join to connect the three layers together. 6.

1. Hot wire cut foam blocks 3. Hot wire cut foam blocks

2. Concrete

Cable wires 3.4.Hot wire cut foam blocks 4.5.Cable Steelwires pipes

1. Hot 6.wire cut foam blocks

2. Concrete

7. Nut

3. Hot wire cut foam blocks

8. Tread rod

4. Cable wires

9. Foam piece

5. Steel pipes

10. Metal plate

7. Nut 8. Tread rod 9. Foam piece

6. Panels join to connect the three layers together.

10. Metal plate

2. Concrete

1. Hot wire cut foam blocks

3. Bottom layer: Foam

7. Nut

6. 7. Nut

8. Tread rod

8. Tread rod 9. Foam piece

5.6.Steel pipes Panels join to connect the

9. Foam piece

6.three Panelslayers join totogether. connect the three layers together.

10. Metal plate

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CASTING EXPERIMENT

S C A L E 1 .1 0 pouring concrete from bottom to top We poured concrete through a plastic tube of 50mm diameter at the centre of the structure. The concrete mix contained sand, cement, 10mm aggregates, water and plasticizer. The casting process took place from bottom to top. Some deformation occured due to two reasons. The casting didnâ&#x20AC;&#x2122;t happen in one go and the fixtures got loosened as the pressure from the concrete increased. When our mold was half full we started pouring from the corners. After the casting process finished the concrete was left to set for approximately 3 days. Then we flipped the model to remove the wooden frame, the PVC textile and the wiremesh. The foam was not removed. The concrete finishing was glossy the first day but it got matte during the next days.

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HOUSE DESIGN

APPL IC AT IO N O F T H E M E T H O D Even though the building method proposed in this exercise is still in an experimental stage we invastigated briefly how it could be transformed into a fully functional private residence. The concrete core of the house is used as the main structural system and design element. The facade is simple glazing. All uses are arranged around the core apart from the bathroom which is placed inside the concrete element.

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0.5

+4.50

+3.70

+0.85

+0.00

0.5

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THAN K . YO U