Technology report - part a march year 2
granada restoration school alex warren 33193582
contents chapter i
chapter ii
chapter iii
2 chapter i: contextual analysis
17 chapter iii: building description
3 4 5 6
site location design proposition & technical challenges granada overview context overview
18 development images
7 8 9
climate: wind & water climate: heat & light climate: shadow studies
10 program analysis: spatial 11 program analysis: environmental
chapter iv
21 elevations 23 plans 26 context 27 3d images (key areas)
12 chapter ii: precedent analysis
31 chapter iv: structure & materials
environmental: 13 royal opera house production workshop 14 environmental: wool warehouse, uruguay
32 Structure: Retaining Walls 33 Structure: Large Span Structures
technical: 15 crossway house 16 ‘bubble’ houses
34 Material Considerations 35 Tactic Development - Timbrel Vaulting 37 Dead & Live Loads 38 Foundations 39 References
1
chapter i: contextual analysis
2
The Alhambra: visited by 2-3 million tourists per year
Alhambra View: tourists directly face the site
site section
The recessed River Darro Gorge 10m below the site
Protected view to The Alhambra infront of the site
Narrow access streets of The Albaicin behind the site
FLAMENCO CAVES
ALBAICIN
The site is located in a gorge north of The Alhambra, on the main tourist trail between the city centre and the city’s famous flamenco caves. TOURIST AREA
It is an unused piece of land in the hillside underneath a juvenile therapy centre, south facing, offering elevated views of the Alhambra with good links to both the therapy centre above and the tourist area in front of the site.
THE ALHAMBRA PALACE N
site location @ 1:5000
CITY CENTRE 3
design proposition
expand restoration school
redesign retaining wall
existing layout
proposed design
The nearby Centro Albaicin restoration school is too small for purpose, so my design will relocate and expand the large workshop areas into this new identified site.
The existing retaining wall greets over 5000 tourists per day as they alight from coaches and walk south west to the main tourist restaurant area; with views to and from The Alhambra.
The existing therapy entrance is convoluted and the retaining wall an eyesore. The blue areas are 800sq.m of administration, accessed from the east. Red areas are tourist restaurants.
My proposal is to excavate the retained earth to allow 3 storeys of restoration workshop spaces, with the administration block relocated to one side and supporting facilities to the west.
identifying the main technical challenges:
climate: heat & light
large span spaces
vernacular construction
retaining wall
The site is south facing in an increasingly hot climate. Direct sunlight cannot be allowed to enter the workshop spaces, damaging the works.
Large restoration projects require large, well-ventilated column-free and double height spaces; workshop typologies that mustn’t deviate from the vernacular architecture.
The site is in the heart of a conservation area (green area) and on the main tourist trail through the city (orange arrow), so this dictates a considered vernacular construction.
The design must prop up an existing juvenile therapy centre towards the back of the site, acting as a flying buttress or retaining wall. 4
site analysis: granada overview Location
01
m 1492. e clearly ent of the
traced newer he walls e city.
Population Statistics
1981
246,642
1991
255,212
2011 2001
Ten Year Average
240,661
2011 2011
Ten Year Average
236,982
Population Statistics - Granada is the 13th largest urban area in Spain.
The city of Granada is located in region of Granada, Andalucia, Southern Spain.
location
The city of Granada is located in the region of Granada, Andalucia, Southern Spain.
Student Population - Granada’s two universities make the city popular with students, causing a fluctuating population. 2000 People Population Statistics - Granada is the Student Population - Granada’s two 13th largest urban area in Spain. universities make the city popular with students, 04 causing a fluctuating population. 01
population
tourism
Granada’s population is currently just over 239,000 but has been decreasing year after year. It’s youth and student population however has been steadily increasing, currently at around 60,000. Youth unemployment in Spain is at a staggering 40% (more than twice that of the UK), so tackling this is one of my design intentions.
The Alhambra (above) is a Moorish/Islamic palace on its own hill in the centre of the city, the main focal point for the annual 5 million visiting tourists. Tourism contributes substantially to Granada’s economy so my design must fit in to the tourists’ idea of Granada’s vernacular and open its doors to allow tourists to see restoration projects.
Timeline Timeline of Religious of Religious Changes Changes
Population Statistics, male and female, slightly more females than the national average.
The city expanded north of the river along the remaining flat land in a more organized grid layout before reaching the hills to the north.
Granada developed in a vague grid layout along the fertile lands south of the River Darro.
01
Airport numbers comparing Granada to Malaga. Granada is a local airport whilst Malaga serves tourists.
Population Statistics, male and female, slightly more females than the national average.
growth
The grid pattern leading into the disorganized settlements that surround the hills is clearly visible from the above.
0202 02
Granada, like most cities, expanded from a small settlement alongside a water source. Granada’s flat, fertile lands were colonised first, with settlements gradually being built further from the River Darro and into the hills to the east.
04 Tourist Concentration map in Granada. Red dots indicate photograph locations uploaded to Google Maps. The main cluster is around The Alhambra, south of my site (in orange) with further tourist photo hot spots around the Albaicin hill to the north looking back across the gorge to the Alhambra.
Timeline Timeline of Significant of Significant Events Events
Airport numbers comparing Granada to Malaga. Granada is a local airport whilst Malaga serves tourists.
01
The remaining buildable areas outside the grid layout became more irregular because of the contours of the land.
Tourist Concentration in Granada. Red dots indicate photograph locations uploaded to Google Maps. The main cluster is around The Alhambra, with further tourist photo hotspots around the Albaicin hill to the north.
history Granada started as an Iberian settlement in the Albaicín district north of my site. Muslim forces took over from the Visigoths in 711, with the aid of the Jewish community. IN the mid-13th century Muslims sought refuge in Granada, where Mohammed ibn Yusuf ibn Nasr set up an independent emirate, ruled from the increasingly lavish Alhambra palace
These diagrams show tourist visits to Andalusia per month. As expected, more tourists visit in summer, but Granada’s warm climate means the city is popular for winter breaks, especially amongst Spanish tourists. These diagrams show tourist visits to Andalusia per month. As expected, more tourists visit in summer, but Granada’s warm climate means the city is popular for winter breaks, especially amongst Spanish tourists.
02 02 02 02 for 250 years. Granada became one of the richest cities in medieval Europe, full of traders and artisans. However in the 15th century the economy stagnated and violent rivalry developed over the succession. 1482 saw a civil war, won by the Christians, and religious persecution soon ensued. Jews were expelled from Spain, and persecution of Muslims led to
01
02 revolts across the former emirate and their eventual expulsion from Spain in the 17th century. Lacking these talented artisans, Granada sank into a deep decline until the Romantic movement from the 1830s. This lead to the restoration of Granada’s Islamic heritage and the arrival of tourism which has continued to define Granada to this day. 5
site analysis: context
topology
context: adjacent building
The site is a very steep 1 in 8 gradient from the bottom of the gorge near the tourist restaurants to the top of the juvenile therapy centre. My site is at the front of the centre, replacing a retaining wall holding back 3 storeys (9.5m) of earth, so must deal with a huge loading of earth pushing down against it.
The juvenile therapy centre offers a service for children (typically teenagers) with behavioural and emotional disorders, who for various reasons (behaviour/drugs) are unable to fit into society. My proposal is to link this centre with the new expanded restoration school, offering construction courses that also tackle Spain’s 42% youth unemployment.
PLAZA DE SAN NICHOLAS
access: site deliveries Roads suitable for site deliveries (lorries) Roads for smaller vehicles (too narrow for lorries) The only suitable road for future delivery lorries runs along the east and south of the site.
juvenile therapy centre Administration
Education
Assessment (day centre)
Accommodation
Therapy / treatment
Entrance
FLAMENCO CAVES
access: important routes The main route from the city centre to the city’s famous flamenco caves and the Plaza de San Nicholas, an elevated public square offering elevated views over the city runs past the site. Tourists’ access must therefore be maintained during the construction phase.
noise control RESIDENTIAL
HOTELS
services STUDENTS
The site sits on the edge of a built-up area of The Albaicin, populated mainly by elderly locals, so workshop noises must be kept inside the building as much as possible.
Mains water, gas, electricity and telephone cables are located under pavements either side of the site; and also exist inside the retained earth (dashed arrows) which I intend to excavate to create my site, so these would need to be re-provided.
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Seasonal Wind Speed & Direction Seasonal Wind Speed & Direction
climate: wind & water
Prevailing Wind Day
Summer
Spring
Summer
Spring Autumn
Summer Winter
Annual Rainfall Winter
Autumn
Winter
generally
13
and South West. There isn’t much seasonal variation - as expected the winds are slightly stronger and are more varied in winter, but only by an average of 1-2 m/s.
13 13
Cool air from the gorge mayPrevailing be used toWind naturally ventilate the building at night, but the site is shaded from winds during Night night pattern the day due to the AlhambraAtHill to the thewind south. Wind turbines switches.not Coolappropriate air from the or ventilation towers are therefore - natural Sierra Nevada mountains ventilation should be provided at east lowsinks leveldown nearthe the gorge. to the
As expected, areas around the coast and mountainous regions experience high rainfall. Granada itself does not experience a lot of precipitation as rain usually falls on the Sierra Nevada mountains to the east.
Ecotect aerial analysis switches. Cool air fromofthe Granada, showing how Sierra Nevada mountains theto height the down palacethe the eastofsinks shades area north of valley,the funnelling the wind theand hill creating from higha winds breezy during day at time. tourist route low level.
During the day the south-westerly winds are obstructed by the topography of the Alhambra hill. The wind rises over The Alhambra but because of its warmth and lightness it stays well above the gorge.
Ecotect Analysis Day
valley, funnelling the wind and creating a breezy tourist route at low level.
13
Site 13 m/s Prevailing Wind Prevailing Wind - Night At night the wind pattern Cool air from the Night switches. Sierra Nevada mountains
to the east sinks down the At night the wind pattern valley, funnelling the wind switches. Cool air from and the creating a breezy tourist route at low level. Sierra Nevada mountains to the east sinks down the valley, funnelling the wind 0 m/s and creating a breezy tourist route at low level.
Site Average Wind Speed - Night Ecotect Analysis Day
Ecotect Analysis Night At night the wind speeds reduce, but wind flow down the gorge is visible as pink on this diagram. Wind direction switches from the south-west to the east, cooling the gorge.
Ecotect aerial analysis of Granada, showing how the height of the palace shades the area north of the hill from high winds during day time.
Alhambra Hill Ecotect Analysis Night
13
At night the wind pattern Maximum Monthly Wind Speed (m/s) switches. Cool air from the Sierra Nevada mountains to the east sinks down the Average Monthly Wind Speed (m/s) valley, funnelling the wind and creating a breezy tourist route at low level.
summary
Prevailing winds in Granada generally come from the West 13
13
Granada
13
Prevailing Wind Night
Autumn
in
During the day thecome from the West and West. There isn’t much south-westerly windsSouth seasonal variation - as expected Winds in are Granada winds strongergenerally and are are obstructed by thethe comemore from thein winter. West and varied topography of theSouth West. There isn’t much seasonal variation - as expected Alhambra hill. The windthe winds are stronger and are rises over The Alhambra more varied in winter. but because of its warmth and lightness it stays well above the gorge.
Winter
wind: prevailing 13
Average Wind Speed - Day
more are varied in winter. the winds stronger and are more varied in winter.
Prevailing Wind Day Winds
Prevailing Wind Ecotect Analysis Night At nightDay the wind pattern
Ecotect aerial analysis of Granada, showing how the height of the palace shades the area north of the hill from high winds during day time.
During the day the south-westerly winds are obstructed by the topography of the Alhambra hill.Speed Thegenerally wind Seasonal & Direction Winds inWind Granada rises over The come from the Alhambra West and Winds in Granada generally but because ofSpeed itsWest warmth South West. There isn’t much come from the and Seasonal Wind & Direction seasonal variation as expected and lightness it -stays well South West. There isn’t much the winds are stronger and are seasonal variation as expected above the gorge.
Summer
Spring
Winds in Granada generally come from the West and South West. There isn’t much seasonal variation - as expected the winds are stronger and are more varied in winter.
topography of the Alhambra hill. The wind rises over The Alhambra but because of its warmth and lightness it staysPrevailing well Wind above the gorge. Day
Alhambra Hill
13
At night the wind speeds reduce, but wind flow down the gorge is visible as pink on this diagram. Wind direction switches from the south-west to the east, cooling the gorge.
da 13 y
night
During 13 the day the south-westerly winds are obstructed by the topography of the Alhambra hill. The wind rises over the hill but because of its warmth it stays well above the gorge. At night however the wind pattern switches. Cool air from the Sierra Nevada mountains to the east sinks down the gorge, funnelling the wind and creating a breeze at low level.
Ecotect Ecotect aerial analysis of Granada, showing how the height Analysis of The Alhambra hill shades the area to the north from high Night At nightday the wind winds during time.speeds reduce, but speeds wind flow At night the wind reduce, but wind flow down the down the gorge is visible gorge as is pink visible in pink on this diagram. Wind direction on this diagram. Wind switches to the east, cooling the gorge. switches fromdirection the south-west
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from the south-west to the east, cooling the gorge.
Typical River Darro Level
Annual Rainfall Predicted Change in Rainfall
1990
1995
Tourist Area in front of site Drainage
13
2000
13
2005 HIghest Recorded River Level Heavy Rainfall
As expected, areas around the coast and mountainous regions experience high rainfall. Granada itself does not experience a lot of precipitation as rain usually falls on the Sierra Nevada mountains to the east.
Predicted Change in Rainfall
As Granada’s climate becomes more arid, rainfall will drop considerably. In winter months rainfall could fall by about 50%, meaning water preservation is very important to the city.
water: rainfall
future rainfall
Predictably, areas around the coast and mountainous regions experience high rainfall. Granada itself does not experience a lot of precipitation (averages around 361mm per year) as rain usually falls on the Sierra Nevada mountains to the east.
As Granada’s climate becomes more arid, rainfall is expected to drop considerably. In winter months, meteorologists predict that rainfall could fall by up to 50%, meaning water preservation (rainwater harvesting, grey-water recycling etc) is very important to the city and any new buildings proposed.
As Granada’s climate becomes more arid, rainfall will drop considerably. In winter months rainfall could
2010
11
Drought
Meteorologists have been documenting the Sahara desert moving northwards into southern Europe, with Granada (red dot) in the area most likely to be affected. Temperatures are slowly rising and rainfall is slightly reducig, a pattern which is expected to continue in the future.
20m 15m 10m 5m 0m
flood risk & drainage Rainwater from the Albaicin region, if not collected for reuse, drains down the hill into the River Darro gorge. 15m was the maximum recorded water level of the River Darro in the (20m deep) gorge directly in front of my site. As the climate becomes more arid, the water levels are expected to decrease so there is a very small chance of flooding. 7
climate: heat & light Granada is located in hot Southern Spain. As desertification and global warming increase temperatures, new buildings in the city must deal with the heat, especially if they are south facing. Maximum Temperatures
Summer Solstice Minimum Temperatures
Winter Solstice
Summer Solstice
Maximum Temperatures
Annual Sunlight (Kilowatt Hours)
Winter Solstice
Annual Sunlight (Kilowatt Hours)
Minimum Temperatures
heat
summer solstice Granada, highlighted in blue,
witnesses sun rise Annual average minimum temperatures are high overlaid at 5.55 and sun set at 20.36. Due to it’s arc onto the maximum temperature graph to display the shown sunlightinlevel inwitnesses the city issun notrise affected by the the Granada, blue, at 5:55am and large fluctuations, averaging 13 degrees surrounding mountain range.centigrade.
The maximum temperature in the summer months in Granada regularly exceeds 30 degrees, of which In winter temperatures remain 10 degrees more the highest recorded wasabove 43 degrees. In and, winter importantly, the maximum temperatures in the summer temperatures remain above 10 degrees.
sun set at 20:39pm. Due to the sun’s high arc in summer, the sunlight level in the city is not affected by the surrounding Sierra Nevada mountain range.
months regularly exceed 30 degrees, with the highest recorded temperature being 43 degrees.
Granada, highlighted in blue, witnesses sun rise at 5.55 and sun set at 20.36. Due to it’s high arc the sunlight level in the city is not affected by the surrounding mountain range. Seasonal Sun Angles
Hours of Sunlight
The maximum temperature in the summer months in Granada regularly exceeds 30 degrees, of which the highest recorded was 43 degrees. In winter temperatures remain above 10 degrees.
winter solstice In winter the city witnesses sun rise at 6.25 and sun set
at 17.58. Due to it’s low arc the suns shadows across Granada arewitnesses greatly affected by7:25am the surrounding In winter the city sun rise at and sun set at terrain. 17:01pm. Due to the sun’s low arc in winter, the sunlight levels
in the city are greatly affected by the surrounding terrain, especially areas north of the Alhambra hill.
In winter the city witnesses sun rise at 6.25 and sun set at 17.58. Due to it’s low arc the suns shadows across Granada are greatly affected by the surrounding terrain.
future temperatures Meteorologists have been documenting the climate of the Sahara desert moving northwards into southern Europe, with Granada (red dot) in the area most likely to be affected. Temperatures will slowly rise and rainfall is expected to reduce in the future, leading to periods of drought.
Annual average minimum temperatures are overlaid onto the maximum temperature graph to display the large fluctuations, averaging 13 degrees centigrade.
Seasonal Sun Angles
Hours of Sunlight
In winter there are five hours of sunlight on average throughout the city. Most areas in Granada receive over 10 hours of sun in the summer months, especially south of The Alhambra hill.
10
10
In winter there are five hours of sunlight on average throughout the city. Most areas in Granada receive over 10 hours of sun in the summer months, especially south of The Alhambra hill.
light
In winter there are 5 hours of sunlight on average, and in summer most areas of Granada receive over 10 hours of sunlight. This means I should design the workshop spaces to minimise sunlight.
Solar shading systems in Granada must be designed Average temperature of Spain showing fluctuation work with the sun angles in the city. Inthe summer, any of louvres temperature. Granada, highlighted in angled black, shows or shading system must be to the an average76.3 temperature 18-20 degrees. sun angleoftoaround work properly.
Solar shading systems in Granada must be designed work with the sun angles in the city. In summer, any louvres or shading system must be angled to the 76.3 sun angle to work properly.
summer solstice
10
spring & autumn equinoxes
Average temperature of Spain showing the fluctuation of temperature. Granada, highlighted in black, shows an average temperature of around 18-20 degrees.
76.3°
53.3°
winter solstice 29. 4°
the 29. 4 degree sun in winter, as direct sunlight can 10resist distract workers and damage restoration pieces.
Solar shading systems in Granada must be designed to work with the sun angles in the city. In summer, any louvres (or other system) must be angled to combat the 76.3 degree sun angle.
Additionally, shading systems at the front of my design must
This sunpath diagram illustrates the summer and winter solstice sunpaths, showing how the summer sun surrounds the site, affecting the south, east and west facades, and the winter sun only affecting the southern facade. 8
climate: shadow studies site SHADOW STUDIES SITE I undertook shadow studies on the site at 8am, 12pm, 4pm and 8pm on the 21st of March, June, September and December (spring & autumn equinox and the winter & summer solstices); using Sketchup with the sun set at its correct location in Granada (Spain) to acheive a broad range of results. SPRING 8AM
The composite image (left) overlays all sixteen shadow studies on to the site. The darkest areas indicate areas most in shadow, noticably the gorge and the narrow streets in the Albaicin area behind the site.
SPRING 12PM
Trees and adjacent buildings offer small amounts of shading to the westernmost corner; but the majority of the site is exposed to the sun all year round as it is south facing on a 1 in 8 gradient hill. This means the roof and all three (west, south & east) facades must offer solar protection to the building, especially the central workshop and therapeutic spaces.
SPRING 4PM
SPRING 8PM
SPRING
composite image (summary)
SUMMER 8AM
SUMMER 12PM
AUTUMN 8AM
AUTUMN 12PM
WINTER 8AM
WINTER 12PM
SUMMER 4PM
SUMMER 8PM
AUTUMN 4PM
AUTUMN 8PM
WINTER 4PM
WINTER 8PM
summer
autumn
winter
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program analysis: spatial
Staff Areas (Private)
Staff WCs, Storage & Servers
Staff Offices
Restoration School Entrance
Plant Room
Computer Suite
Cafe & Kitchen
Changing, WCs & Showers
Main Restoration Workshop
Tourist Entrance
Support Workshop
Delivery Entrance & Storage
Existing Coach Drop-off
Printing Room
3 key circulation routes (Existing) Juvenile Therapy Entrance Restoration School Entrance Tourist Entrance
Staff Areas (Private)
Link to Existing Centre
Therapy Entrance
Staff Meeting Rooms
Therapy Workshop
Changing Area
Reception & Waiting Area
Staff Offices
Delivery Entrance & Storage
Therapy Showers & WCs
Mental Health Assess.
Staff WCs, Storage & Servers
relationship diagram RESTORATION SCHOOL Restoration school employees enter from the west, where there is a route to the existing centre through the Albiacin (below). Workshops are accessed via a changing area, with a smaller support workshop taking deliveries. Private staff areas are separated, with a cafe, offices and a computer suite.
TOURIST PROMOTION Tourists enter centrally from the south via an existing coach drop off, that connects my site to the busy tourist restaurant area in the gorge between The Alhambra and the Albaicin. Tourists can observe the restoration projects in the main workshop space but not the more private therapy spaces.
CONSTRUCTION THERAPY Using the existing therapy entrance, psychosocial teenagers enter the construction therapy workshop through the changing area after a mental health assessment. Private staff areas are separated, containing offices and meeting rooms. A delivery entrance opens into storage for workshop supplies.
serviced zones The site is accessed from the east, south and west, with the most private part area (black dot) at the north-west behind the new restoration school entrance. This should be where ventilation/HVAC ducts exit the building’s plant room. Workshop equipment (saws, drills etc) are best placed at the back of the site so extraction services can be more discrete.
The existing Centro Albaicin restoration school is located just over 400m to the west through the Albaicin. 10
program analysis: environmental key areas:
construction workshops
external tourist areas
entrance & waiting areas
office spaces
(Main workshop, support & therapy workshops) • Extraction equipment for power tools • Cooling - natural ventilation if possible to reduce costs • Heating - not as important as cooling, required in winter • Natural Lighting - utilise Granada sun, but no direct sunlight • Artificial Lighting - so restorers can best see their work • Acoustics - to reduce workshop noise where possible • Shading - from south facing Granada’s direct sunlight
• Shading - Using colonnades created by brick catenaries • Heating - none required externally • Natural Lighting & Ventilation - external, south facing • Artificial Lighting - street lighting might suffice
• Cooling - natural ventilation if possible to reduce costs • Heating - not as important as cooling, required in winter • Natural Lighting - utilise Granada sun, but no direct sunlight • Artificial Lighting - use all day
• Cooling - natural ventilation if possible to reduce costs • Ventilation - for hot computers • Heating - not as important as cooling, required in winter • Natural Lighting - utilise Granada sun, but no direct sunlight • Artificial Lighting - used all-day
workshop storage areas
wcs & shower areas
plant room
cafe & kitchen
(For both restoration and therapy workshops) • Cooling - natural ventilation if possible to reduce costs • Heating - not essential for material storage • Natural Lighting - not essential • Artificial Lighting - although used infrequently • Shading - to protect materials from direct sunlight
(For both restoration and therapy workshops) • Cooling - natural ventilation if possible to reduce costs • Ventilation - extracting odours • Dehumidifiers - for shower areas • Heating - not as important as cooling, required in winter • Natural Lighting - not as important as other spaces • Artificial Lighting - used all day • Water Recycling - grey/waste water
• Cooling - air conditioning offers most reliability • Heating - air-con to keep temperatures at 18-20°c • Extraction equipment from workshop spaces • Natural Lighting - not required • Artificial Lighting - infrequent use, motion-sensors • Acoustics - reducing equipment noise
(For the Restoration School) • Dehumidifiers - for the kitchen • Cooling - natural ventilation if possible to reduce costs • Heating - not as important as cooling, required in winter • Natural Lighting - utilise Granada sun, but no direct sunlight • Artificial Lighting - so restorers can best see their work • Shading - from south facing Granada’s direct sunlight
changing areas
mental health assessment
server rooms
circulation spaces
(For both restoration and therapy workshops) • Cooling - natural ventilation if possible to reduce costs • Heating - not too important for short-stay space • Natural Lighting - not essential • Artificial Lighting - important, used frequently
• Cooling - natural ventilation to reduce noise • Heating - not as important as cooling, required in winter • Natural Lighting - not essential, but helps orientation • Artificial Lighting - infrequent use, motion-sensors
• Cooling - air conditioning offers most reliability • Heating - air-con to keep temperatures at 18-20°c • Natural Lighting - not practical, this would affect cooling • Artificial Lighting - infrequent use, motion-sensors
(For both restoration and therapy areas) • Cooling - natural ventilation if possible to reduce costs • Heating - not as important as cooling, required in winter • Natural Lighting - not essential, but helps orientation • Artificial Lighting - important, used frequently
other areas:
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chapter ii: precedent analysis
12
environmental precedent: Royal Opera House Production Workshop by nicholas hare architects precedent chosen because... SIZE - Set designs and scenery for the Royal Opera House (London) are constructed inside a triple height, column-free workshop space; similar to how large architectural domes and vaults will be constructed in my restoration school under a similar sized large span roof structure.
COMFORT - Naturally ventilated areas provide more comfortable working conditions. Heating comes from an underground geothermal source, and heat is helped kept inside by insulative sedum roof. The roof arch is orientated east-west so direct sunlight doesn’t enter the interior space.
STRENGTH - The roof trusses were engineered to hang large structures on pulley systems below, and a sedum roof above.
ORGANISATION - Office & education areas are on the first floor, looking down on to the workshop space below - this is important so sets can be seen as they would be in the opera house. A double height entrance allows lorries inside to load scenery without subjecting it to the weather outside.
LIGHT - Roof openings were designed to ensure natural light illuminates the workshop spaces evenly and without glare, providing comfortable working conditions.
Precipitation 13m Wind
Prop Hanging Pile Foundations
fabrication strategy Natural Light
Dead Loads (Structure)
Artificial Lighting runs
Live Exterior Loads (compressive load)
Delivery Access
Live Interior Loads (tension loads)
Views down into workshop space
Sedum Roof Load
Each of the 10 steel trusses were prefabricated in Ireland, and split into five, 16m long sections for ease of transportation. These galvanised circular hollow sections were bolted and welded together on site, creating a total arch length of 82m.
lighting strategy
structural strategy
heating & cooling strategy rooflight detail
Translucent triple-skinned, 32mm-thick, 1,500mm-wide polycarbonate rooflights allow diffused light into the workshop. Artificial light allows more precise work, provided by rows of fluorescent tubes suspended from the underside of the trusses.
Translucent triple-skinned, 32mm-thick, 1,500mm-wide polycarbonate rooflights allow diffused light into the workshop. Artificial light allows more precise work, provided by rows of fluorescent tubes suspended from the underside of the trusses.
The building uses a geothermal heat pump provided by a 100m deep bore hole adjacent to the building. This system loses heat to the ground in summer and absorbs ground heat in winter, when the pipes are circulated with anti-freeze.
insulation strategy
water strategy
acoustic strategy
The sedum roof provides good insulation and thermal stability, as well as contributing to biodiversity, which has helped the building to achieve an ‘excellent’ Breeam rating.
The sedum roof helps to reduce water run-off by absorbing rainwater. The roof doesn’t have a gutter - water runs off the roof into a pebble margin with a ground drain beneath.
To provide the building with good working conditions, profiled sound-absorbing perforated aluminium panels were clipped to a subframe that was in turn connected to the trusses.
1 - Galvanised circular hollow steel section roof truss 2 - Translucent triple-skinned, 32mm-thick, 1,500mm-wide polycarbonate rooflight 3 - Polyester powder-coated profiled aluminium acoustic truss lining 4 - Polyester, powder-coated aluminium rooflight kerb lining 5 - Continuous fluorescent lighting units suspended from bottom truss chord 6 - Cableway 7 - Profiled, insulated roof deck panel spanning top truss chord members 8 - PIR insulation board upstand between galvanised closers, incorporating SHS rooflight support posts 9 - Sedum mat on Bauder roofing membrane and root barrier, incorporating retention strips and irrigation system with roofing membrane dressed up and over-rooflight kerb 10 - Mansafe post fixed to roof deck with Bauder capping sheeet fully welded to Mansafe post.
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environmental precedent: wool warehouse near montevideo, uruguay by eladio dieste
precedent chosen because...
gaussian vaults
primary structure
technical challenges
The expense of bringing electricity to rural Uruguay meant that the structure had to provide as much natural light as possible to illuminate the warehouse. However, wool discolours in direct sunlight so the roof had to be optimised so that no direct sunlight entered.
Eladio Dieste trained as an architect in Catalonia, and became famous for his Gaussian vaults, thin-shell roof structures in single-thickness brick, that derive their stiffness and strength from a double curvature catenary arch. Like Gaudi, Dieste used hanging chains to find these (inversed) roof forms.
These images show the warehouse without its perimeter walls, showing off the primary structure. For this brief study I will just be concentrating on the primary roof structure, as the basic (brick) wall construction around the four sides is of no significance.
LIGHT - provide as much natural light as possible to illuminate the warehouse without direct sunlight that would discolour wool. The site has no mains electricity for artificial lighting. RAINWATER - The building is not connected to mains water so the simple WC & sink have to utilise grey water.
Drainage Profile
Roof Profile
N Rainwater Storage Tanks
Reinforced Concrete Columns
sunpath geometry
s - shaped roof profile
drainage
grasshopper experiment
The maximum sun angle on this site in Uruguay is 78 degrees from horizontal (orange arrow above). The minimum winter angle (32 degrees) is not important because if the glazing were to be angled at 32 degrees then summer sun would enter the warehouse and discolour the wool.
I have highlighted the S shape profile (above) in the centre of the vault in between the two flat sides where the vault rests on the structural column grid. The benefit of this profile over, for instance, a linear central profile, is that it creates drainage channels for rainwater collection without affecting sunlight.
The S-shaped catenaries are raised in the centre to allow rainwater drainage into storage tanks along either flanking wall, via a full length gutter. Montevideo (Uruguay), like Granada, has a dry climate so rainwater retention is important, saving the client money connecting to mains water.
I used Grasshopper3d software to visualise the roof structure for these diagrams. The benefit of this method is that parameters can be set up to control sun angle, width, height, length and number of vaulting systems, so the system can easily and quickly be adjusted for a different site.
14
technical precedent: crossway house
precedent chosen because...
form finding
formwork
The house is designed underneath a timbrel vaulted arch structure, innovative because this medieval construction technique has rarely been used since its re-emergence by Gaudi in the 19th Century. The arch is self supporting - none of the house’s walls bare any weight of the arch.
Vernacular construction: 26,000 tiles were collected within a few miles of the site, with a 3-man team laying 260 per day (100 day construction). Lime mortar and plaster of paris are easily sourced - none of the materials are particularly unusual, only the geometry is.
Fabric is held in place at the edges and hung. Once set in place, the form is inverted and the tensile strength becomes a vertical compressive strength. However this method only allows simple form, compared to chain hanging or digital form finding which allow much more complicated designs.
The formwork is uniform across the entire arch, typically 3 tiles wide and 4 tall. It acts as a guide, enabling workers to lay the tiles to the correct geometry, ensuring the arch’s strength.
The traditional herringbone method offers no structural advantages, just aesthetic, so wasn’t chosen because it would be hidden by a green roof that rests above.
Stretcher bond was used for construction ease. Tiles are held together with plaster of paris, which dries in 10 seconds. Only 2 edges of each tile is plastered for a tile to hold itself in place.
Second layer of running bond tiles rotated 45 degrees to ensure no joints overlap, with a layer of cement mortar in between that speeds up construction.
Third layer of running bond tiles rotated 90 degrees from original. More layers were then added (rotated 45° each time) for strength and increased insulation (aided by green roof).
Perpendicular Angle
Catenary Geometry Compressive Load Paths
25 300 150
Foundation Loads
simultaneous construction
tile proportions
angled base connection
plaster vs mortar mixes
The different layers of tiles were laid simultaneously across the structure until they eventually met in the centre of the catenary arch.
These are typical Guastavino tile dimension used on the project. The important dimensions however are the ratios, where length = twice the width.
Flat bases offer poor connections where the tiled arches meet the ground, so bases are angled perpendicular to the catenary curve to ensure ground forces are evenly distributed.
Plaster of Paris is stronger, dries quicker, but is difficult to work with so is only used on the first layer. Mortar dries slower so can be made in larger batches, speeding up construction. 15
technical precedent: ‘bubble houses’
precedent chosen because...
‘ ‘Airform’ construction utilises the natural geometric strength of inflated membranes and encases it in the natural material strength of reinforced concrete. Combining geometric and material strength leads to an earthquake-resistant construction that is buildable by low-skilled workers in 2 days.
background
‘ A proposed solution to the post-war housing crisis, ‘Bubble Houses’ were concrete domes formed around an inflatable rubber (neoprene nylon) balloon, buildable in just 2 days. The same single balloon was used as a guide to construct all of the houses in one development.
construction speed & ease
pros & cons
Because so few trades were required, a bubble house could often be constructed in two days, larger ones in 3-4 days (plus furnishing & painting). The natural geometric strength of these bubble houses made them hurricane and even earthquake resistant. Below: construction process.
PROS: price (materials & labour), construction speed, simple construction - skills are easily taught. CONS: weather - airform is in-situ, so only constructed in hot countries (to help concrete dry). Difficult to connect to.
construction sequence
1) FOUNDATIONS Circular trench dug to take the reinforced ring beam (radial trench foundations) of the dome structure. The PVC membrane is anchored in place.
2) INFLATION A heavy duty neoprene nylon balloon; which is more commonly used to make dry-suits (heavy duty waterproof wet-suits) is inflated.
3) GUNITE & REINFORCEMENT A grid of steel cables are spread over the dome for structural reinforcement, and an initial layer of gunite (sprayed concrete) is applied by hose.
4) INSULATION & 2ND LAYER OF GUNITE Once the first layer has dried, a layer of insulation is added and another layer of gunite is applied; which is the final external finish (which can be painted onto).
5) VIBRATION To ensure an even spread, concrete vibrators are used. These are standard engineering systems used in most road/bridge construction, powered by electric motors.
6) DEFLATED MEMBRANE Once the sprayed concrete mix has dried it is structurally self-supporting due to the natural geometric strength inherited from the pneumatic membrane; now deflated.
7) MEMBRANE CLEANING The membrane is cleaned (jet washed), dried (fan heaters) and folded up, ready to be used again on other projects.
8) OPENINGS & FINISHES The remainder of the concrete mix is used to fill the radial trench foundation, openings cut into the structure and paint applied, if required. 16
chapter iii: building description
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building description: development images
sketchbook images A series of sketches from my sketchbook, experimenting with ideas ranging from scale, views, access, circulation, shading, large span spaces, walkways and rainwater collection.
Once I discovered that a 3 storey building could be accessed from a recessed slope rather than a fourth storey with circulation, the structure began to take its current form.
therapy staircase I designed an L shaped stair because it helps define the construction therapy space. My design priority was to give visitors in the waiting area a view down into the therapy workshop, but this stair design would block these views.
basic fire strategy By kinking the retaining wall and recessing the stair, this creates a lobby the far side of the waiting area, allowing views down in to the construction therapy workshop.
The Albaicin hill steepness (1 in 8) allows me to design fire exits at first floor level to avoid people trying to escape down through the workshop space. The side entrance is also the workers entrance to the restoration school.
Fire proof cores are shown in the centre to meet Part B regulations - if the cores were to be placed at either end of the two blocks, travel distances would exceed regulations. 18
building description: arch development
new computational methods
why use these methods?
Above: virtual chain hanging that creates digital versions of catenary arches, using Kangaroo Physics software.
Forms popularised by Gaudi were rare because the engineering process (right) was very labour intensive. Rather than going through this process of hanging chains and calculating a series of known points to then inverse, computational methods have advanced that digitise this process, saving time, money, and allowing accurate visualisations of architectural proposals.
digitised form-finding: my grasshopper script
catenary line
divide line
force direction
I wrote this Grasshopper3d script to digitally recreate the real world forces that cause chains to hang using Kangaroo Physics software; virtually recreating Gaudi’s famous chain hanging form finding experiments in a fraction of the time.
script explanation I start by importing the CATENARY LINES I want to become catenary curves and can use DIVIDE LINE to create the number of rings on these digital chains. I specify a FORCE DIRECTION to ensure these chains hang vertically, with FORCE PARAMETERS to more accurately visualise the speed & stiffness of the artifical gravity. STATIC POINTS are set at the ends of the chain so they are not affected by forces. KANGAROO PHYSICS is the physics engine that everything plugs into, and finally I add an ARCH THICKNESS so the 1d lines become coherent arches.
static points
force parameters
kangaroo physics
arch thickness
how this script helped:
1) I drew the basic elevation grid in Rhino software, with roofsupporting column grid and floor heights which would act as the template for the catenary facade geometry.
2) I used my Grasshopper script to virtually hang chains to span workshop spaces and support the roof structure above.
3) Inverting these catenaries created the basic catenary structural system, with arch heights increasing above the large workshop spaces.
4) I then raised the arches in the 3 workshop spaces to allow more usable space around the central columns. 19
building description: arch development
1 - early development
2 - larger catenary arches
The large catenaries arches over workshop areas start at first floor level to create more workshop space along the column lines. Brickwork continues into the support spaces either side.
In-fill catenaries are enlarged (see development below) to allow access for equipment and machinery at high levels. This enables elevated walkways/lighting rigs to be hung.
3 - sunlight optimisation
4 - environmental facade
The roof formwork is inflated to different pressures so that more light enters the main workshop space. VIsually this adds a sense of central hierarchy, helping reinforce the symmetry.
Weatherproof and soundproof facade added along the second & third grid line, creating a public colonnade in front that shades tourists as well as the workshop spaces.
modular arch development Using the same digital techniques I had used for the main elevation catenaries, I started off by sub-dividing the infill section into human proportions for access though. However, as with the larger scale catenaries, starting the arch at ground level creates unusable space by the columns.
Again, like the large scale catenaries supporting the roof structure; raising the base point of the catenary arch creates a more practical opening. This space now feels less cramped and uses less brick.
By not dividing up each infill section it is now possible to create a space large enough to pass materials, equipment, walkways etc through, whilst not sacrificing human scale.
Opening up the supporting brickwork allows more light to pass through, views out and the space to be better ventilated. It also works somewhat to emphasise the geometry, advertising the skills taught at the restoration school. 20
building description: drawings
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section aa @ 1:200
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This section shows the new circulation into the therapy centre and the tourist entrance into the building, below the naturally ventilated inside/outside office spaces.
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east elevation @ 1:200 1 - Coach Drop-off 2 - Tourist Restaurant Area 3 - Deliveries & Storage
4 - Office Spaces 5 - Outdoor Break-out 6 - Workshop Showers
7 - Entrance Walkway 8 - Therapy Entrance 9 - 1F Fire Exit
This elevation shows the steep 1 in 8 gradient leading down from the Albaicin past the building, allowing a first floor fire exit at the rear or the site on either side. 21
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This long section shows the main workshop space flanked by the therapy workshop (right) and the support workshop (left), both with supporting facilities either side.
My proposal retains the symmetry of the juvenile therapy centre behind using the main workshop space as the central hierarchy, using larger roofs to allow more light inside.
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elevation perspective (nts)
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1 - Existing Coach Drop-off 2 - Key tourist routes through the Albaicin area
3 - Flamenco Museum 4 - Hotels 5 - Existing Therapy Centre
The main frontage is the facade that tourists see when looking down from The Alhambra viewing gallery. The existing coach drop off area in front of the site encourages tourists inside .
(2) The tourist routes lead to the city’s famous flamenco caves to the east and the Plaza De San Nicolas, a viewing gallery at the top of the Albaicin, with elevated views across the city. 22
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key 1 - Support Workshop 2 - Primary Workshop 3 - Therapy Workshop 4 - Material Storage 5 - Changing (Overalls/Aprons)
workshop deliveries 6 & 7 - Showers (F/M) 8 - WCs (M, F, Accessible) 9 - General Storage 10 - M&E (Ductwork) Void 11 - Tourist Shop/Market
The delivery areas are both undercover (to protect materials from weather) and have direct acces into the workshop stores. Construction Therapy Restoration School 23
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key 1 - Restoration School Entrance 2 - Office 3 - Computer Suite & Printing 4 - Break-out Space 5 - Therapy Centre Office
natural ventilation 6 - Office Break-out Space 7 - Meeting Room 8 - WCs (M, F, Accessible) 9 - General Storage 10 - Server Room
All offices (including those on the 2nd floor) are naturally ventilated, cooling computers and creating a more pleasant working environment. Break-out spaces offer fresh air without leaving the building, with views to the Alhambra. 24
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key 1 - Therapy Entrance 2 - Therapy Reception 3 - Therapy Waiting Area 4 - Mental Health Assessment 5 - Therapy Centre Office
extraction equipment 6 - Office Break-out Space 7 - Plant Room 8 - WCs (M, F, Accessible) 9 - General Storage 10 - Workshop Entrance
All workshop machinery is located at the rear of the workshop space for discretion (not blocking views to The Alhambra palace). A full height, 1250mm duct-work void runs behind all the workshop spaces, leading to the plant room. 25
maximum sun angle 76.3°
alhambra viewing gallery
The glazing angle is 76.3 degrees (maximum sun angle in summer) so workshop spaces are naturally well lit, but no direct sunlight can damage restoration pieces.
5 million tourists look down from The Alhambra’s viewing gallery each year, so my proposal had to be built using local materials and techniques to help contextualise it.
section looking west
Roof 3 2 1
contextual 3 storey height All buildings along the gorge are 3 storeys tall plus (one storey) pitched roofs. My proposal maintains this height, with the storeys clearly defined on the facades. It also follows the footprint of the existing retaining wall, maintaining the gorge’s building line.
The scale of my building is put into perspective when it is seen in the same context as the River Darro gorge and the Alhambra Palace. My scheme fits in with the surrounding 3 storey buildings, maintaining views and the building line; whilst still offering naturally lit, triple height workshop spaces.
unobstructed views to the alhambra Nearly every building the Albaicin are has a view of the palace, and my proposal does not interfere. The elasticated rubber pneumatic formwork is inflated to different pressures so roofs step down in size towards the therapy cenre, maintaining these views.
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context plan @ 1:1250 My design follows the existing footprint so does not alter the building line.
key 1 - Existing Coach Drop-off 2 - Tourist Restaurants 3 - Flamenco Museum 4 - Hotels 5 - Arts Centre Car Park
6 - Existing Therapy Entrance 7 - New Therapy Entrance 8 - Extract /Rainwater 9 - Public Gardens 10 - View east along gorge
(10) approach view My design follows the existing footprint so does not alter the building line. Its natural angle means that tourists can see the building as they walk east through the gorge past the restaurant area and up in to the Albaicin area.
There is currently a tourist coach drop-off / pick-up point directly in front of the site, so the building opens itself up to encourage these tourists inside to see the work of the restoration school. 26
key spaces: main fabrication workshop The largest workshop space, triple height and open plan to allow construction practice of large scale brick & tile Catalan structures. The timbrel vaulted roofs are designed so allow as much natural light in as possible without direct light glare. The modular catenary brickwork system is strong enough to support elevated walkways, gantries and suspended equipment; constructed in a way that celebrates the methods taught in the centre. Tourists are encouraged to observe the processes to promote the business and potentially collect new commissions. 27
therapy main entrance A private, tranquil pathway leads to a domestic scaled (designed to be less intimidating for psychosocial teenagers) therapy entrance, with the view south to The Alhambra in the background, an advert for the construction techniques taught in the centre.
therapy workshop entrance Challenging the idea of psychosocial teenagers being daunted by the scale of the world around them; they instead look down to the workshop space from the safety of a domestic scaled entrance. The journey becomes lighter, with views through the structure; which is clearly expressed and constructed using the methods the restoration school teaches.
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roof structure Pneumatically formed Catalan tiled roof structures let only ambient north light into the workshop space below. The elasticity of the cushion means the roofs can step down in size using the same formwork, maintaining views from the existing therapy centre (directly behind) towards The Alhambra.
looking west Tourists walking from the city’s famous flamenco caves down to the city centre pass through the colonnade, looking south to The Alhambra. On the first and second floors, the naturally ventilated office and restoration school cafe spaces look south towards the palace. The sheltered external spaces offer a private respite from the main office areas, and allow cool air from the gorge to naturally ventilate the building.
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support workshop This is where the materials get delivered, cut to size and all machine work takes place before the main assembly in the adjacent workshop. Restoration school workers enter from the first floor via a tiled staircase with delicate iron catenary banisters; which is L-shaped to allow head clearance past the catenary brick arch, formed with Kangaroo Physics and Grasshopper.
office space Employees and employers will soon realise the hassle of relocating offices was worth it once they enter the new office space on the first and second floors. The semi-outdoor break out / lunch spaces have views south to The Alhambra, help naturally ventilate the offices and protect them from direct sunlight. Roof lights let in ambient north light, reducing the need for artificial lighting.
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chapter iv: Bore Hole Samples 1
Soil
structure & materials 2
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Gravel Geological build up based on bore hole samples
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structural considerations: retaining wall
Earth Loads (compressive) Reactive Loads (equal & opposite to earth loads) Gravity Loads (of retaining wall)
why?
anchored wall
piling wall
anchored piling wall
Because if a poorly designed retaining wall were to collapse, the earth supporting a juvenile therapy centre, home to over 20 orphans, would crash through my new restoration school into a major tourist area, blocking a major route in a picturesque world heritage site.
This basic type of retaining wall resembles a floor slab with pile foundations rotated 90 degrees. Cables are driven into the earth and fixed by one-direction expanding anchors, that keep the wall in place using tension strength.
Using long piles that extend vertically directly underneath the main retaining wall, the wall is held together by soil pressures on either side, allowing it to take high loads because the load is in equilibrium - essentially pushing back against itself.
This hybrid system uses a typical piling wall construction and drives piles in to the earth that expand and act as anchors. This method may be suitable for my site because piles can be driven into the earth before the main construction of the restoration school commences.
gravity wall
cantilevered wall
buttresses
anchored cantilever
These simple walls are angled so they are bottom heavy, but they are relatively weak when holding back a large amount of earth so are rarely used in large constructions. This would be the worst option as it would not be strong enough to suport three storeys of compact earth.
Cantilevered walls use an extended section to stabilise itself using the same earth pressure trying to topple it over. This wouldn’t be suitable where the cantilever would meet an obstruction, such as a large water body, but may be appropriate for my site.
Buttresses are good ways of holding back earth but the major disadvantage of course is that they intrude the space directly below the wall. My catenary arches are strong in vertical compression but weak under horizontal loads so would be unsuitable to act as buttresses.
This hybrid method is suitable when pile foundations may not be appropriate, keeping construction just below ground level whilst utilising the strengths of cantilevered and anchored retaining wall systems. This may not be appropriate because the angle eats into space at the base.
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structural considerations: large span structures
steel structures
concrete shells
timber frames / grid shells
pneumatic structures
PROS • The obvious choice for any large span space (because of:) • Straightforward manufacture • Allows for pre-fabrication • Can be engineered to include light openings • Design flexibility • Strength and durability
PROS • Well-documented, straightforward manufacture • Strength and durability • Can be constructed in-situ
PROS • Straightforward manufacture • Allows for pre-fabrication • Can be easily engineered to include light openings • Design flexibility • Strength and durability (although less than concrete/steel)
PROS • Straightforward & cheap manufacture (modular segments) • Straightforward & cheap fabrication (inflation) • The deflated structure can be easily transported to site • Can be designed to include light openings
CONS • Not vernacular, so unsuitable for a UNESCO heritage site. • Difficulty delivering large elements on steep, narrow roads.
vernacular construction Granada is rich in Islamic and Moorish architecture. Brick arches, courtyards and shaded colonnades are common especially in in The Alhambra, where arches of differing scales and rhythms are used to define key areas. The Alhambra viewing gallery looks directly down to my site so vernacular construction is particularly important in this context.
CONS • Not vernacular, so unsuitable for a UNESCO heritage site. • Pre-fabrication possible but rare - large sections would struggle to be transported along the steep, narrow raods. • Not as much design flexibility as steel or timber • Create dark spaces underneath so must be artificially lit
chosen strategies:
CONS • Not vernacular, so unsuitable for a UNESCO heritage site. • Difficulty delivering large elements on steep, narrow roads.
CONS • Not vernacular, so unsuitable for a UNESCO heritage site. • Poor strength and durability, unless specified with aramid fibres or high pressure silicone rubber - but this would lead to difficult manufacture and hugely increased costs. • Air lock required to enter a low pressure structure • Not much design flexibility (compared to timber or steel)
brick arches & timbrel vaults PROS • Appropriate for a UNESCO world heritage site • Makes use of the skills taught by the restoration school • In-situ construction eliminates large delivery lorries • Design flexibility • Strength and durability
PROS • Timbrel vaults have good geometric strength • Computerised design methods make design easier CONS • Pre-fabrication not possible (adding time & expense) 33
material considerations
catenary arches Catenary arches are based on the inverse of the geometry a chain naturally hangs at. Catalan architect Gaudi made famous this method of form finding for large arch structures, and his student Cesar Martinell i Brunet perfected the technique to create large span spaces for wine storage.
You say to a brick, 'What do you want, brick?' And brick says to you, 'I like an arch.' And you say to brick, 'Look, I want one, too, but arches are expensive and I can use a concrete lintel.' And then you say: 'What do you think of that, brick?' Brick says: 'I like an arch.' Louis Kahn
Inverted Hanging Chain Geometry Inverted Hanging Chain Geometry
Form Finding Hanging Chain Form Finding Hanging Chain
dead & live loads
wind loads
The main structural consideration is that the brick arch must be self-supporting over the large spans of the workshop spaces. Live loads such as people, furniture or vehicles are not applicable on the roof structure, so the main structural consideration of each arch is the dead load of its own weight.
The site sits in the River Darro gorge that runs from the Sierra Nevada mountains to the east. This gorge brings with it strong winds that should be resisted by the structure to prevent shear twisting.
buildability
locally sourced materials
durability & life cycle
security & fire
My design intention is to use the skills taught to the workers at the restoration school I am expanding to construct the new workshop spaces. Brick arches are commonly taught in the centre, so the building construction itself will become a lesson for students taking architectural restoration classes.
The existing Centro Albaicin restoration school uses bricks sourced from a local quarry just 5km from the site. Water for the mortar mix can be collected from rainwater storage tanks. Once brick arches and timbrel vaults are constructed, they require very little maintenance.
The brick arches of The Alhambra and the nearby catenary arches of Catalonia have stood strong for over a hundred years. I intend for the similar brick and timbrel vaulting of the new restoration school to stand strong for a similar amount of time, and to specify either aged or reclaimed bricks to make it more contextual in the world heritage site.
Both brick arches and timbrel vaulting have good resistance to fire ignition and fire spread, one of the reasons they have been standing in Granada and other Moorish architecture in the surrounding regions for hundreds of years. Their durability makes them secure and difficult to sabotage.
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tactic development:
timbrel vaulting
why timbrel vaulting? STRENGTH The catenary curves are self-supporting because of their geometric strength rather than their material strength. SPAN Timbrel vaults can span 20-30m, ideal over workshop spaces. MATERIALS Tiles can be sourced cheaply and locally, and are vernacular. LABOUR The technique is low-tech and surprisingly straightforward to construct (see diagrams below) so can be quickly taught and learnt in the restoration school.
construction sequence
initial (timber) formwork
tiling method
formwork removal
formwork removal
A series of catenary formed timber arches support the Catalan tiling above. The larger the formwork spacing, the less accurate the tiling; leading to a weaker arch geometry.
Tile workers from different sides meet in the centre. 2 or 3 layers of tiles are used to strengthen the catenary structure, supported with plaster or mortar in between.
If all the timber formwork arches are not all removed at once, stress points will act on the surface (red circles); which could lead to cracking.
Therefore all timber formwork has to be removed simultaneously to eliminate surface stresses. This can be done on a movable/hydraulic surface or automated joints.
BASE geometry
INCREASED roof light
angled glazing
inverse lower arch
The most basic iteration - vertical glazing and a flat base; but still forming double curvature constructable by means of timbrel vaulting.
Increases glazing size and so increasing the amount of light fed inside, but there would be a maximum angle each roof light could be constructed at.
(Chosen development) this layout follows the sun’s movement, allowing more ambient light inside because of the light bouncing off the roof north of each section of glazing.
This geometry lets the most ambient light inside whilst still following the sun’s path from the previous design iteration. However it creates recessed areas that would lead to ponding. 35
tactic development:
timbrel vaulting
flat chain
hanging chain
flat chain grid
hanging chain grid
This diagram represents a chain laid flat on the ground, divided into a number of segments for clarity
Created with Kangaroo Physics, this is the same chain as previous but it is hung with the digital physics software properties; forming a catenary (idealised) curve.
A pneumatic air cushion is essentially composed of numerous chains creating a mesh across the surface.
Once inflated, the chains remain catenary, forming an idealised surface that can be used as formwork. The more mesh divisions (chains), the smoother the resulting surface.
pneumatic formwork - why? Gaudi popularised hanging chains as a means for form finding. The inverse of these hung chains provided the catenary (idealised) curve geometries that were used to create his famous vaulted ceiling structures, relics of medieval construction in Catalonia starting from the 14th century.
Thinking of a pneumatic structures as a series of infinite catenary curves (catenary surfaces) rather than a single surface helps visualise how useful air filled structures may be in the form finding process, as well as construction guides and safer construction - as workers cannot fall through formwork.
maximum summer sun angle 76.3째
views to the alhambra dead load paths
simple roof structure
developed roof structure
roof in context
My initial proposal involved using one pneumatic cushion inflated to the same pressure each time. This would create the same standardised roof structure across the entire roof span. A non-flexible membrane only becomes catenary once inflated to maximum pressure.
However, using a range of inflation pressures on an elastic pneumatic cushion (silicone rubber) can vary the light levels inside the workshop space and reduce the size of roof lights near existing windows to maintain their view of The Alhambra, making the most out of the elastic membrane.
Once inflated, the tiles are laid over the formwork so the roofs are angled at 76.3째. This ensures even in mid-summer, workshop spaces are well lit but receive no direct sunlight. The cushions can be inflated to different pressures to step down in size so that views to The Alhambra are maintained from the existing juvenile therapy centre.
Pushing back the front facade offers more public space for tourists outside the coach stop; the colonnade creating an overhang that blocks direct sunlight from entering the main workshop space. This means no louvres are required on the south facade - which would not tie in with the architectural vocabulary of the area. 36
structural considerations: dead & live loads snow / rain wind (shear) people furniture work benches
restoration pieces
tourists
structure development
why arches?
live loads
Columns alone would not best support each timbreal vaulted roof. As forces travel across the catenary surface of each roof structure, they must be supported along the perimeter rather than four point loads, which are more suited to columns.
The diagram above shows the top of the new brick arches between these columns. This allows loads passing through the full perimeter to be supported, with surface loads passing evenly down the arches rather than merely 4 points.
SNOW, RAIN & WIND Loads are distributed by the timbrel vaults then catenary brick arches. (Snow build-up is rare in Granada - every 10 years). Wind loads are absorbed by the facade and find their way to the nearest structural arch, then column, then foundations.
PEOPLE, FURNITURE, RESTORATION PIECES Loads pass horizontally along the floor slab until they meet either the nearest column or pad then pile foundation. The concrete floor slabs are strong enough that it doesn’t matter exactly where heavy workshop machinery is placed.
shrinkage & settling loads Movement joints must be designed between key components such as the 3 workshop spaces and the two (3 storey) supporting areas as the structure settles. Shrinkage joints must be specified to allow for the concrete floor slabs to expand as they dry in the heat of Granada.
DEAD LOAD LIVE LOAD
dead loads: roof loads
retained earth load
closed arch structures
open arch structures
These are the loads from the weight of the structure itself, regardless of any live roof loads such as wind, snow or rain. The main loads are taken by the foundations, the large catenary arches that span the 3 workshop spaces, and the structural brick columns that these connect to.
The retained earth is the most substantial load on the structure, so a reinforced concrete retaining wall is required to hold back this pressing force (above). The catenary brick arches’ role is only to support the timbrel vaulted roof, not to the load from the earth weight, as catenary arches are not designed to be under horizontal pressures.
PURPOSE Better structural performance for areas not requiring light
PURPOSE To allow more light, views and/or ventilation
LOADS Loads pass vertically through the in-filled brickwork into the catenary brickwork, then pass into structural columns.
LOADS Loads travel horizontally until they meet either an arch or column. Loads pass down catenary brickwork into columns. 37
primary structure & foundations Bore Hole Locations Bore Hole Samples Bore Hole Samples
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Bore Hole Locations Soil
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Map showing bore hole locations.
geological build up
12 12 The Sierra Nevada mountains to the east of Granada were formed when the African continental plateSedimentary collided with 12 the Eurasian plate to the north. Granada sits primarily on limestone (right), a sedimentary rock which has Soil become a common building material in the region.
Silt
Silt
Soil
Silt
12
12
Sand
Clay
Sand Soil
12
Gravel
Soil
Soil
Soil
Clay
Sand
Silt
Surface Soil Sand
Gravel
Silt
Clay
When constructing a large building on soils containing clay, pile foundations should be used to ensure the structure can reach through the soft soils and anchor to a Geological build up based on bore hole samples solid base
retaining wall
(secondary) partition walls glass balustrades
Gravel
pile foundations
Geological build up based on bore hole samples
Silt
Containstiled mainly slates, roof but is difficult to extract in structure this region
& Quartzites r. concrete
concrete Carbonates floor slabs
Clay
12 build up based on bore hole samples Bore hole data shows that the site sits onGeological primarily clay soils, When constructing a large building such as my proposal 12 Silt limestoneGravel Clay Sand 12Predominantly 12 be used to ensure the under a thin layer of surfaceGeological soil. Although under 12 on clay soils, pile foundations should build up based compacted on bore hole samples - commonly used for Sand the weight of the earth above, clay soils are susceptible to structure can reach through the soft soils and anchor to a solid Clay Gravel 12 Sand 12 building in the area Geological build up based on bore hole samples movement. To maintain structural integrity on these soils, base. Pad foundations might be appropriate under the point Clay Clay Gravel deep pile foundations willsamples be required. load of12 the arches with steel reinforced concrete piles below. Geological build up based on bore hole Limestone Gravel 12 12
catenary Metapelites brickwork
pad and pile foundations
Geological build up based on bore hole samples Gravel
bore hole data
Sand
Marble - widely used facade in religious structures glazing due to its high quality sculptural finish
break-out space
office
break-out space
office
tourist entrance
storage
therapy entrance
shwr
Pile Foundations
primary structure
secondary structure
why is this appropriate?
The primary structure includes the reinforced concrete floor slabs, the catenary brick arches and the foundations. Behind this sits the retaining wall, which is the most important primary structural element, as it prevents the weight of the earth and the existing juvenile therapy centre behindPaleozoic the site from collapsing forwards into my new restoration school.
The secondary structure includes elements such as the roofs, which only support the weight of themselves (unlike the arches, which support the weight roofsisand brickwork Thisof zone above); and the partition walls, which are not load-bearing. predominantly made of These should be simple stud-work & plaster walls, a skill a stone called greywake already taught at the restoration school. - A hard, course grained sandstone
My design removes the retaining wall, which is an eyesore in the middle of a world heritage site, and replaces it with a new tourist attraction and new facilities for the Granada restoration school and juvenile therapy centre. My chosen structure is vernacular as it uses techniques taught at the school to solve the key technical challenges. Map showing bore hole locations. 38
references
books
online resources
Most of my reading material was on the subject of pneumatic structures and the engineering properties they have - something I exploited to optimise my timbrel vaulted roof. Other books include topics on scripted architecture to enable me to visualise these forms.
Granada (general) http://www.andalucia.com/cities/granada/history.htm http://www.lovegranada.com/ http://www.alhambradegranada.org/en/ http://lostislamichistory.com/granada-the-last-muslim-kingdom-of-spain/
Dent, R. (1971). Principles of Pneumatic Architecture. Architectural Press. London Head, J. (2011). No Nails, No Lumber: The Bubble Houses of Wallace Neff. New York: Princeton Architectural Press. Kuoni, C. (2004). Thin Skin: The Fickle Nature Of Bubbles, Spheres, And Inflatable Structures. 1st ed. New York: Independent Curators Inc. Roland, C (1970). Frei Otto: Structures. London: Praeger Publishers. Uffelan, C. (2008), Pure Plastic: New Materials for Today’s Architecture. Berlin: Verlagshaus Braun Publishing. All images found in the online resources (right) with the exception of site photos, which I took in person in Granada last year.
Climate Information http://www.suncalc.net/#/37.1948,-3.6166,11/2014.01.03/01:40 http://granadainfo.com/climate.htm http://usa.autodesk.com/ecotect-analysis/ http://www.horca.net/graphs/sunplot.php Restoration School http://www.crnartesania.com/ Gaudi http://whc.unesco.org/en/list/320 http://www.gaudiexperiencia.com/ Royal Opera House Production Workshop http://www.roh.org.uk/news/thurrock-production-workshop-awarded-architecture-oscar http://www.nicholashare.co.uk/
academic Books and websites regarding Spanish architect/engineer Eladio Dieste are scarce so I turned to academic papers, found online at: University of Edinburgh http://www.research.ed.ac.uk/portal/files/4959198/Pedreschi_Theodossopoulos_ICE_ stbu160_003.pdf University of Seville http://www.arquitecturatropical.org/EDITORIAL/documents/DIESTE%20J%20M%20 CABEZAS.pdf University of Oregon http://www.btesonline.org/connector/Connector_Vol10_01.pdf http://www.arct.cam.ac.uk/Downloads/ichs/vol-3-2451-2468-pedreschi.pdf
Crossway House http://www.hawkesarchitecture.co.uk/grand-design http://crossway.tumblr.com/ Airform Construction http://latimesblogs.latimes.com/home_blog/2011/12/wallace-neff-shell-house.html http://www.geo-dome.co.uk/article.asp?uname=monolithic_dome http://www.monolithic.com/stories/inflating-an-airform-and-regulating-air-pressure Retaining Walls http://www.tensarcorp.com/Systems-and-Products/Mesa-Retaining-Wall-Systems http://www.anchorwall.com/ Foundations http://eeg.geoscienceworld.org/content/18/3/217.short http://www.iberianature.com/material/spaingeology.html http://www.builderandengineer.co.uk/feature/ piled-foundations-exploration-their-suitability-and-construction http://constructionstudiesq1.weebly.com/piled-foundation.html
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