KNIT SKIN ANNE EBERY - MAJOR PROJECT 2021 S2
CONTENTS
1. Why Knit? 2. Why Re-Skin? 3. Early Work 4. Re-Focus
Page 03 Page 10 Page 15 Page 26
Knit Skin reskins a modernist, curtain-walled skyscraper in Melbourne’s CBD using an architectural knitted membrane. A knitted membrane is a meta material, emergent from the combination of fibre and stitch morphology. It’s a material of structural contingency and limitation, so baked into the design process is a consideration of material and its manifold specificities. The project engages with Melbourne’s already built, mid-century office towers, not as reified heritage ‘icons’, and not as ecopathic stumbling blocks in our vision of a utopic sustainable future, whose riddle we might solve if only we came up with the perfect new build. Rather, these buildings are an already-existing ecology to team up with. Knit Skin proposes the knitted membrane as a lightweight, ultra-strong solar array and sunshade, an energy source for the city, draped on and between existing towers, exploiting and being exploited like lichen on a log. The knitted membranes define social space, dapple light, and provide a radically different street level experience. The project explores the opportunities in an architecture of strategic weakness and material constraint, and aims to eke more pleasure and utility from an already existing urban ecology.
1. This project is about knitted membranes in architecture. Why?
2. knitted textiles are meta-materials. The combination of a technique and a material. The materials can be photovoltaic, air filtering, solar active, carbon fibre or combinations thereof. Knitting gives us the opportunity to create complex double curved geometries, lightweight and customizable. Those properties come hand in glove with constraints: how do you make it
2_1 Hyrbid Textile Tower, CITA Denmark, 2017 image: Anders Ingvartsen
stand up for example?
3. In the garment industry a distinction is made between “cut-and-sew” and “fully fashioned” garments. One is subtractive and necessarily creates waste, the other shapes the material, in the making, and is additive.
1_16
228 Queen Street
FULLY FASHIONED
NO WASTE
CUT-AND-SEW
SAMPLE 1 WALES: 40 COURSES: 60
SAMPLE 2 WALES: 40 COURSES: 60
4. What makes knitting “knitting” is the convoluted loop-in-loop structure made up of wales and courses, that you can think of like courses of bricks. On the right are samples; same number of courses and wales, same yarn fibre, very different performance.
COURSES
5. Facing page: On the left of each these panels is the knitting code. Increases and decreases are shown in purple and green.
WALES
code
knitted panel
code
knitted panel
code
knitted panel
increase decrease
1
direction of fabrication
2
3
6. Contiguous ‘interior’ and ‘exterior’ surfaces; complex double curves.
1. Why Knit? 2. Why Re-Skin? 3. Early Work 4. Re-Focus
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7.
This project tests the possibilities and aims to push the limits of
architectural knitted materials by reskinning a building in Melbourne’s CBD.
8. Between 1960 and 2000 Melbourne CBD had a surge of building, mostly of office towers skinned with curtain walls. So that’s condition one: Melbourne is basically built. Condition two is a heating biosphere and consequent weather extremes, exacerbated by the city’s heat-island, in turn exacerbated by ubiquitous curtain walls. The city’s facades may not be best equipped to weather our near future, but they’re what we’ve got and they embody a lot of carbon and capital. I was inspired by Donald Ryan’s Shearing layers of change: A building Is always tearing itself apart.
1_1
480 Collins Street
1_2
99 William Street
1_3
350 Queen Street
1_4
473 Bourke Street _1970
1_5
333 Queen Street
1_6
555 Lonsdale Street
1_7
200 Queen Street _1993
1_8
575 Bourke Street
1_9
530 Collins Street
1_11
228 Queen St
1_12 339 Lonsdale Street
1_10 Bourke Place
Embodied _Carbon _Capital _Labour _Culture _Technique _Assumptions _Logistics _Values 1_13 550 Lonsdale Street
1_14 440 Elizabeth Street
1_15 483 Swanston Street
1_16 40/140 William Street
1. Why Knit? 2. Why Re-Skin? 3. Early Work 4. Re-Focus
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2_3 Isolate Surface
2_4 Define cast-on; edges, and cast-off
2_5 Define wale count
2_6 Define density
2_1 Concept; views
2_2 Exploded Parallel Projection
2_7 Get stitch directions
2_8 Final knitmesh
9. It was important to establish a method for creating accurate physical models from the CAD geometries to establish a testing and feedback loop.
2_9 Translation of mesh into code for production
ELEVATION 1
ELEVATION 2
20 mm
0 333 mm
1000 mm
333 mm
333 mm
20 mm
100
200
0
2_2
550 Lonsdale Street
side A
side B
Knit stitch - standard
Tuck stitch Allows two materials simultaneously
10. Different techniques allow us to combine two or more materials with different transparency and strength. the sample at top right produced with consistent courses and wales throughout, the sample at right also with consistent total courses and wales, but with a randomly generated pattern of increases and decreases every fourth course.
increase decrease
11. During the first phase of the project, the site chosen was a chunk at the Western end of Bourke Street, encompassing Eagle House, the RACV club and the former BHP House, now called 140 William.
1. Why Knit? 2. Why Re-Skin? 3. Early Work 4. Re-Focus
Page 03 Page 10 Page 15 Page 24
13. The project re-focssued on 140 William Street, aka BHP House, on the corner of William and Bourke.
14. Built between 1969 and 1972, designed by Yuncken and Freeman, modernist, and heritage listed.
Beautiful, laconic. The rational 4x4m grid style implying a logic, implacability; a givenness.
Strong foreground/background distinction.
15. 2700mm floor to ceiling, uninterrupted free space on every floor, circulation and services in the core; hidden. To paraphrase ecology writer Timothy Morton: the smooth hidden functioning of smooth hidden functioning.
16. Allowing extraordinary climactic conditions to exist, almost imperceptibly. An aesthetics of invisible utility. Making a show of not making a show of the fantastic amounts of energy it takes to keep on keeping on.
17. There are opportunities inherent to this already existing ecosystem of buldings. City roofs as is provide some opportunity for solar harvesting, but the area is limited, and the vertical curtain walls are generally inneffective hosts for solar panels, since only the northern facades will have solar access and other buildings may cast shade for too much of the day. Additionally panels may block some or all of the view from the building.
When we deploy solar panels we generally have two strategies: stacking or arraying. A stacked array was tested, angled at the optimal 38 degrees for Melbourne’s sun angle.
However, a second approach tested the array being draped from the top of the building, achieving a cone of 38 degrees anlges solar array with more acute 45 degree angles at West and East to respond to those sun angles.
The lightweight array approach affords the opportunity to tailor the shape of the intervention, like a tailored suit; cutting away areas that see too much shade, precisely angling areas to respond to local conditions.
Shadowing was tested over the course of a day in summer, and a combination of the stacking and spreading approach was tested, to optimize solar exposure, while keeing views from neighbouring buildings and from BHP House, and allowing the array to cling to the facade where protection from harsh sunlight is needed. the different layers of transparencies in the knitted fabric allow natural light penetration and often modulate views rather than blocking them. The array was refined and altered as feasible cable routes and spans from building to building were tested. The form achieves at least 1400 kwh/m2 on 80% of the array.
18. Solarvoltaic yarns with the idea of knitted modules to both provide shade and harvest solar energy. This technology exists now, the precedent on the right is dutch designer Pauline van Dongen’s backpack made with solar yarn.
Hours of solar radiation kwH/m2
18
12
7
2
Hours of solar radiation kwH/m2
18
12
7
2
19. Testing arrays for hours of solar radiation throughout the year showed that the most effective harvesting strategy explpited the gap between existing buildings. The extended build site is viewed as an ecology to team up with, where affordances and benefits are negotiated.
20. The proposal is a lightweight façade-and-array hybrid, that can make use of the southside lee of the building, that can shade BHP house and the surrounding buildings from harsh Western and Eastern sun, reduce glare, dapple light, and where it meets street level, gently deliniate social spaces and provide soft street furniture.
Net cable mesh structures were explored, eventuating as a hybrid of cable net carrying a individul knitted modules.
NORTH ELEVATION
SOUTH ELEVATION
EAST ELEVATION
WEST ELEVATION
21. The project continously looped through scales of the micro [the stitch technique, form and fibre] the meso [the level of individual module] and the macro [the intra building mesh]. At the level of the module, the project invstigates deesigns that require minimal structure, can achieve variable surface angle and curvature through simple alterations, and creates apertures for views out of the building and to glimpse the original form under its new skin. the proposed module design consists of knitted membrane, flexible diagonal brace element and rigid horizontal spar or yardarm which is anchored to the floor slab, where the spar holds the knit and the flexible cross-members in opposition. The attachment frequency and interval is therefore based on the existing glazing grid and the column and slabs under it. However the lightweight stucture disengages with the facade at times supported by conection points, masts and cables. The module design allows the fabric to be pre-tensioned, twisted at top and bottom, with and addition acute counterdirectional curve at the mid point. 22. The basic module can be pushed and pulled, manipulated and transformed as it responds to different conditions around the site. The array has no overarching form without its host. Like lichen agentially it’s somewhere near the bottom, so it positions itself strategically. Resources like positioning, shading and structure are shared.
MODULE CRITERIA
ENGAGES WITH THE GRID OF THE EXISTING GLAZING
ABILITY TO CUSTOMIZE TO RESPOND TO LOCAL CONDITIONS
ABILITY TO CHANGE APERTURE SIZE
ABILITY TO CHANGE SURFACE AREA AND ANGLE
PROVIDES SEVERAL DIFFERENT DEGREES OF TRANSPARENCY
CAN BE FABRICATED CONTINUOUSLY
THE SHAPE OF THE DESIGN PRE-TENSIONS THE KNIT
ONLY ACHIEVABLE WITH KNIT, NOT WITH A WOVEN MEMBRANE
ABILITY TO INCORPORATE TWO+ MATERIALS IN KNIT
Street Furniture
Hours of solar radiation kwH/m2
18
12
7
2
1. Vertical strips of fabric dapple hard East and West light
Summer Solstice solar noon 75* Equinox solar noon 52* Winter Solstice solar noon 29*
2. Horizontal bulge of fabric at floor slabs dapple northern light in Summer and not Winter
3.Apertures between vertical fabric strips allow building inhabitants views; translucent knitted fabric dapples light
TYPICAL FLOOR EXISTING SHADOWS AT NORTH-FACING WINDOWS SOLAR NOON, SUMMER SOLSTICE
TYPICAL FLOOR SHADOWS AT NORTH-FACING WINDOWS SOLAR NOON, SUMMER SOLSTICE
TYPICAL FLOOR SHADOWS AT NORTH-FACING WINDOWS SOLAR NOON, WINTER SOLSTICE
ROOF PLAN
SECTION A - A
10
40
SECTION B - B
10
40
NORTH FACADE, BHP HOUSE
CGU building corner South Elevation
CGU building corner West Elevation 1
3
5
1
3
5
VIEWS TO AND FROM WILLIAM STREET, SOUTH OF BHP HOUSE
BHP HOUSE CARPARK LANEWAY
VIEW WEST, BOURKE STREET MALL
AERIAL CITY VIEW, LOOKING NORTH