DEVELOPMENT OF P E R M A N E N T, F L O AT I N G & ERODING STRUCTURE IN THE ‘HOTEL FOR EXPERIENCING REAL VENICE’ ARUB SAQIB UNIT 3 ENVS 3006 DESIGN TECHNOLOGY TECHNICAL REPORT APRIL 2011
CONTENTS Abstract Chapter 1: Introduction Chapter 2: Context Chapter 3: Permanent Structure Chapter 4: Floating Structure Chapter 5: Eroding Structure Conclusion Appendix Bibliography
ABSTRACT This technical dissertation puts forward a number of strategies that allow the building to engage with its fluctuating environment in Venice. To address the problems of an extreme high tide, strategies have been explored as a means to accommodate the tide instead of working against it. For this reason, ‘reactive’ architecture is explored as appose to a ‘defensive’ one. In particular, I will be focusing on three main structural strategies in my building; that of permanent structure, floating structure and eroding structure. In the case of floating and eroding structures, mechanisms which are normally suppressed in conventional building practice are deployed in an attempt to open up new uses for the building as it interacts with the tide. In a context any other than this ‘Hotel for Experiencing Real Venice’ on the island of Giudecca, these reactive design methods could be read as ‘bad’ design. This study is vital to understand the implications of these two strategies, and whether or not they are feasible. To inform the permanent, ‘good’ design of my building, I have studied the traditional techniques of Venetian architecture as precedent. This is a documentation of the investigation I have taken on, leading up to the final section of the building.
fig. 1 Istrian Stone stairs at the Giudecca Canal, Venice, during Aqua Alta ‘High Tide’
fig. 1 Author’s own image 2011
CHAPTER 1 Introduction
The Lagoon Environment The Venetian lagoon lies between mainland Italy and the northern end of the Adriatic Sea. The lagoon is fifty kilometres in length, and around eight to ten in width. My site, the Island of Guidecca, is situated in the deepest part of the lagoon, facing the Adriatic sea. This section of the lagoon is known as the lagoona viva, or the living lagoon, as it is subjected to the greatest tidal range on the whole of the Adriatic shoreline.1 The tides follow the course of the moon; with the highest tidal range occuring at the new moon and full moon. The tide is at its highest and lowest twice every twenty four hours at these times. The tidal range is at its lowest at the first and last lunar quarters, with only one tide every twenty four hours. Adding to this vast tidal range, the land around the perimetre of the laguna viva is very low, less than two metres above median tide level.2 This renders the land more vunerable to being submerged during high tide episodes. The highest tide ever recorded was 1.94m above sea level in November 1966, and the lowest being 1.21m below sea level.3 This fluctuating environment is the site in which my investigation is situated.
fig. 2 map of the Venetian lagoon
1. Goy, J. Richard, Venetian Vernacular Architecture, Cambridge: Cambridge University Press 1989 p. 5 2. Goy, J. Richard, Venetian Vernacular Architecture, Cambridge: Cambridge University Press 1989 p. 5 3. Goy, J. Richard, Venetian Vernacular Architecture, Cambridge: Cambridge University Press 1989 p. 5
fig 2. Goy, J. Richard, Venetian Vernacular Architecture, Cambridge: Cambridge University Press 1989 p. 6
High Tide ‘Aqua alta’ (high tide) is not a new problem in Venice; the first record of aqua alta dates back to 1240. However, the present situation is significantly worse compared to 100 years ago due to the dramatic increase in frequency of the high tides. Of the ten tides above 140cm recorded from 1902 - 2002, eight occurred after 1960. In the winter of 2002 alone, in the space of three weeks, (14 Nov - 8 Dec) there were 10 flood events above 110cm , five above 120cm, and one above 140cm.4
fig. 4 frequency of floods since 1300s
As a result, the percentage of land covered by water has increased dramatically over the last century (fig.3). As a result, the city has become more difficult for its few inhabitants to occupy. 90% of the city is completely submerged when tides reach above 140cm5; which has become a growing occurrence over the last 30 years (fig.6).
fig. 5 shows an increase in normal tide (+80cm) since 1923
Fig.3 Percentage of Venice submerged at 100 - 140cm above sea level
fig. 6 shows an increase in extreme high tide (>+110cm) over the last 30 years
compared with 1900
4. Da Mosto, Jane, and Fletcher, Caroline, the Science of Saving Venice, London: Umberto Allemandi& Co. 2005, p. 40
fig 3 . Da Mosto, Jane, and Fletcher, Caroline, the Science of Saving Venice, London: Umberto Allemandi& Co. 2005, p. 40
5. Da Mosto, Jane, and Fletcher, Caroline, the Science of Saving Venice, London: Umberto Allemandi& Co. 2005, p. 40
fig 4-6. Da Mosto, Jane, and Fletcher, Caroline, the Science of Saving Venice, London: Umberto Allemandi& Co. 2005, p. 41
Impact of Water on Venice - Seawater The laguna viva consists of seawater bought in by the tides6. Due to the increased frequency of the tidal exchange between the lagoon and the Adriatic, salinity of the canal water is the same as the sea7. The Adriatic has 38.3g salt per every 1kg of water8. The salt in this water is the main factor of decay in most Venetian buildings. The dissolved salts degrade the building fabric, especially brickwork, (fig.7) as they crystallise and expand within the mortar of walls once the water evapourates in a process known as efflorescence9 (fig.8). The Venetians were well aware of the damage to mortar in brickwork, which is why sacrficial layers of plaster renders were applied to all facades. This led me to consider structures designed in the building specifically to erode.
fig. 7 salt damaged brickwork
fig. 8 detail salt efflorescence on brick surfaces
fig. 9 laborious restoration process: injecting waterproof mortar to damaged walls
6. Goy, J. Richard, Venetian Vernacular Architecture, Cambridge: Cambridge University Press 1989 p. 5 7. Da Mosto, Jane, and Fletcher, Caroline, the Science of Saving Venice, London: Umberto Allemandi& Co. 2005, p. 49 8. http://www.croatia-boat-charter.com/adriaticsea.htm 9. Da Mosto, Jane, and Fletcher, Caroline, the Science of Saving Venice, London: Umberto Allemandi& Co. 2005, p. 49
fig 7. Da Mosto, Jane, and Fletcher, Caroline, the Science of Saving Venice, London: Umberto Allemandi& Co. 2005, p. 49 fig. 8 Fletcher, C.A, and Spenser, T., Flooding and Environmental Challenges for Venice and its Lagoon, Cambridge: Cambridge University Press 2005, p.180 fig. 9 Fletcher, C.A, and Spenser, T., Flooding and Environmental Challenges for Venice and its Lagoon, Cambridge: Cambridge University Press 2005, p.167
Water Affecting Venetian Buildings - Lagoon Water The lagoon water is polluted, as the city has always traditionally discharged its waste untreated into the lagoon, relying on the tides to flush the canals clean through waste water outlets10. Today, many of these centuries old outlets have not been maintained, covered by mud clogged by fine sediments that is constantly stirred up by boat traffic (fig.10) and the tides11. This leads to a further accumilation of salts, as well as old pipes disintegrating, and release their contents within the walls of the buildings they are held in.
fig. 10 cross section showing structural damage to building foundations; engine propeller swirling sediment into sewage pipes causing blockage
10. Da Mosto, Jane, and Fletcher, Caroline, the Science of Saving Venice, London: Umberto Allemandi& Co. 2005, p. 49 11. Da Mosto, Jane, and Fletcher, Caroline, the Science of Saving Venice, London: Umberto Allemandi& Co. 2005, p. 49
fig. 10 Da Mosto, Jane, and Fletcher, Caroline, the Science of Saving Venice, London: Umberto Allemandi& Co. 2005, p. 49
Impact of Water on Venetian Buildings - Water Vehicles The laguna viva, being the deepest part of the lagoon, allows for very large vehicles to pass through it (fig. 2). The Giudecca canal is the main route for cruise ships, as it is large enough for the vehicles to manouvre through and allows spectacular views of the main lagoon. Approximately one thousand ships pass through the canal yearly, emitting fine particle pollution such as sulphur dioxide and sulphur trioxide into the air, turning into acid rain12. The rain deteriorates the main compounds in Venice’s marble and Istrian stone foundations; calcite, into calcium sulphate (chalk) which is soluble in the lagoon water. This has lead to a situation where the ‘stones of Venice are dissolving into the air and melting away in the water’13.
fig. 11 mooring cruise ships documented by locals damaging pavements
12. Scheppe, Wolfgang, IUAV, Migropolis, Venice: Hatje Cantz 2010 p. 237 13. Scheppe, Wolfgang, IUAV, Migropolis, Venice: Hatje Cantz 2010 p. 237
fig. 11 Scheppe, Wolfgang, IUAV, Migropolis, Venice: Hatje Cantz 2010 p. 239
Interacting with the Tide Although the tide and the water it brings is slowly degrading the buildings of Venice, there is however a fundamental role that water has played historically in the city . Thus there is a very close proximity to water at which is very unique to Venice; one that embraces the water, as the city is surrounded by it. fig. 12 waves hitting wooden floor decking restaurants
Grass patches (fig.12) have been placed strategically facing the Giudecca Canal, so the soil absorbs the water as it comes in, acting as a marshland. Timber decking in restaurants (fig.13) expose costumers’ feet to the water as it splashes rhythmically between the boards, creating a phenomenon of sound and movement that utalises the tide’s energy. Debris from destroyed buildings is allowed to collect and act as a barrier to prevent the tide from penetrating further into dry land (fig.14).
fig. 13 grass and soil used to absorb incoming tide on main Fondamenta, Giudecca
fig.14 debris piled up from destroyed building, site Giudecca
fig. 12 - 14 Author’s own image 2011
Building Program and Strategy The Hotel for Experiencing Real Venice is designed specifically to host the UNEP (United Nations Environmental Program) conferences on Energy, Climate and Sustainable Development. The designed erosion and flotation of the spaces to the fluctuating tide will make the impact of environment felt strongly, affecting the occupation of the building as strategies are drawn up by Europe’s council to respond to climate change. A series of events spanning five years will host the team of thirty two delegates from 2011 until 2015 as they review UNEP’s Medium Term Strategy. The main strategies that will be explored are the permanent structures, floating structures and eroding structures within the building. The floating structures are positioned at key points in the building. These walls function with the fluctuating level of the tide, rising and falling throughout the day at various points of the building, opening and closing off access to spaces. Buoyant platforms are designed at specific points, raising the floor level with the tide and hosting specific events which will continue despite the rising water level. These platforms are mainly in the conference room of the building, as well as the Flooding Garden. The eroding structures have been designed as sacrificial layers wedged in between the permanent structures of the building. These sacrificial structures gradually deteriorate over time; shifting the spatial qualities of the building as they wear away. This is most evident in ‘the Falling Room’, which rests on columns of sacrificial material that gradually wears away with the tide, allowing the room to alter in height over the course of the five years. fig. 15 Author’s own image 2011
fig. 15 initial proposal immulgamating strategies that interact with the tide
CHAPTER 2 Site context
Site My site is located in Giudecca, on the main Fondamenta san Biago facing the Giudecca canal. It is on an old 19th Century industrial strip that belonged to Molino Stucky; owner of a flour mill that has now been converted to the Molino Hilton hotel, and the Fortuny fabric factory. Due to being on the main Fondamenta in the laguna viva, a lot of large and small water vehicles pass along the site. The hotel itself requires a lot of transport connections. There is a water bus (vaperato) stop to the north of the site, as well as a petrol station to the north east, and three water taxi stops facing the site’s west facade (fig. 15). This frequent vehicle movement adds to agetation of the water in the canal, increasing wave height by 40-50cm14.
VAPERATO STOP
PETROL STATION TAXI STANDS
SITE
fig. 16 site is surrounded by water vehicle stops encouraging a lot of vehicles to pass by the main and tributary canals
14. Fletcher, C.A, and Spenser, T., Flooding and Environmental Challenges for Venice and its Lagoon, Cambridge: Cambridge University fig 16. Author’s own image 2011 Press 2005, p.199
As fig.17 demonstrates, the site lies directly on the route taken by holiday cruise liners. The motor propellers of these vehicles generate between 40,000 - 120, 000 horse power15. Along side cruise liners, the other vehicles I saw whilst on site included vaperatos, industrial ships, water taxis and private speed boats (fig. 19). Although the speeds at which these vehicles move along the canals are controlled by the Venetian authorities, the speed limits on the Giudecca canal range between 11-20km/h (fig. 18), the heighest limit for Venice. These vehicles add further fluctuation to the tide; as can be demonstrated in the diagrams of the next page, comparing tidal levels from 1984 (before the hotel, petrol station and Vaperato stop was built) with 2009.
fig. 18 speed limits of the water vehicles in km/h
fig. 19 vehicles seen on site with their retrospective sizes
fig. 17 map of cruise ships route all passes along Giudecca canal
15. Scheppe, Wolfgang, IUAV, Migropolis, Venice: Hatje Cantz 2010 p. 237
fig 17. Scheppe, Wolfgang, IUAV, Migropolis, Venice: Hatje Cantz 2010 p. 333 fig 18. Atlante della laguna, Venice: Observatorio della Laguna del Territorio 2004 p. 5 fig 19. author’s own image 2011
fig. 20 Western elevation of site facing tributary canal; hourly tide level for December 23rd 2009 has been marked, showing great fluctuation with the highest tide being +143cm at 0500, and the lowest being +12cm at 1900
fig. 20 Western elevation of site facing tributary canal; hourly tide level for December 23rd 1984 has been marked. These tidal levels are recorded before the hotel and adjoining vaperato stop were bult, which resulted in far less motor vehicle activity around the site. The tidal level was a lot lower for this year; the lowest being -53cm and the highest only reaching +62cm.
fig. 20 & 21 Author’s own images 2011
Site at Low Tide and High Tide
fig. 22 Site at low tide, view from junction between Giudecca canal and tributary canal
fig. 23 Site at moderate high tide +110cm above sea level. Hilton pavement raised above the tide whereas my site is submerged
fig. 22 & 23 Author’s own images 2011
Day To Day Living with the tide The Venetians coordinate their everyday activities around the chaotic cycles of an unpredictable tide (fig.24). From grocery shopping (fig.25) to garbage collecting (fig26). fig. 24 Diagrams found on the ‘City of Venice Tide Centre’ website, indicating the tidal level for the day as well as appropriate attire for water levels when manoeuvring through the city
fig.25 Daily garbage collection
fig.26 Daily delivery for local grocery store
24. Image source: http://www.comune.venezia.it/flex/cm/pages/ServeBLOB.php/L/EN/IDPagina/1748) 25-26. Author’s own image 2011
Dispersing the Tide - 1866 Reports have attributed the increased flooding to the rise of sea level; and for Venice in particular, to ‘changes in the lagoon’s physical structure, which affects the entry and movement of water within it. ... the reduction in the total area of lagoon, due to land reclamation and other interventions, so a greater volume of incoming water has less area in which to spread itself.’16 An example of land reclamation projects can be seen in fig. 27. This map from 1866 depicts offshoots from a bend of the Grand Canal near the Rialto that have been filled in order to make pedestrian thoroughfares. This affected the flow of water through the city. Engineer Pietro Paleocapa ‘criticized the attempt to make Venice a ‘dry-land’ city and insisted that, for Venice, canals were the equivalent of vehicular roads.’17
fig. 27 Ugli’s map of the Grand Canal showing open offshoots Marco Perissini’s map of the same area showing the offshoots filled in
16. Da Mosto, Jane, and Fletcher, Caroline, the Science of Saving Venice, London: Umberto Allemandi& Co. 2005, p. 40 17. Pertot, Gianfranco, Venice Extraordinary Maintenance, London: Paul Holberton 2004, p. 23
fig 27. Pertot, Gianfranco, Venice Extraordinary Maintenance, London: Paul Holberton 2004, p. 23
Dispersing the Tide - 2010 I spotted strategies of dealing with the tide that either allowed the water to spread, or desperately tried to keep it out in order to preserve ‘dry land’. As an example of the first strategy, canal walls are lined with channels (fig. 28), allowing the tidal water to flood the adjacent pavement gradually with the rising tide, rather than swelling up in the canals. In this way, the incoming water is allowed to spread over a wider surface area. Owing to his criticism of mistaking Venice for dry land, Paleocapa would have praised this as ‘good design’.
fig.28 detail of channel allowing pavement adjacent to canal to flood
fig.29 canal wall lined with channels
fig.30 buildings with pipes extended from walls and roof; metal gate in
fig.31 elevation of a building
The other strategy engaged in desperate attempts to keep floors dry. Shop keepers and house owners often attach pipes protruding out of the building into the street, emptying the floor’s content of water onto the pavement, adding to the swelling tide. Metal gates about 50cm high were also raised above doors in occupied buildings to prevent the regular, smaller shifts in the tides ranging from +80cm to +110cm above sea level from leaking into the building (fig.31). This interventions are very temporary and ad hoc attempts to deal with the force and regularity of the tide, and can be deemed as ‘bad design’. These observations of the context in Venice have formed the foundation of my investigation, allowing the design of the building to develop around the three main strategies for dealing with the Tide. The first of these strategies to be explored is the permanent structure. This structure will be protected by the two strategies to follow; its preservation vital to the functioning of the hotel
front of door
fig. 28 - 31 Author’s own image 2011
CHAPTER 3 ‘Good design’ - Permanent structures Non-sacrificial structure built to frame the key spaces
Precedent: Half House, Alejandro Aravena Aravena’s concept for the Half House social housing scheme built in Chile was a starting point for thinking about the frame that would house the building. As Aravena criticises prefabricated concrete structures for their inability to adapt to changing situations18. Thus, only half a house is prefabricated, leaving the final solution to be built by the occupant. As time passes, the houses gain value rather than deteriorate; ‘social housing as investment rather than an expense.’19 Taking from this idea, my building will be designed around a permanent non-sacrificial, stationary structure on which the eroding and floating structures of the building depend for stability. To ensure the survival of these permanent structural elements, I have had to study traditional Venetian construction techniques; well versed with the requirements for building in the Lagoon environment. The following chapter documents an investigation fundamental to the feasibility of the whole project. As with the Half House, a permanent frame must be constructed, setting the stage for the sacrificial structures of the building to react with the fluctuating tide.
fig. 32 Aravena’s Half House housing project, skeletal prefab frame before and after occupation
18. http://www.alejandroaravena.com/obras/vivienda-housing/elemental/ 19. McGuirk, Justine, Alajandro Aravena, Icon Magazine Online, January 2009
fig. 32 image source: http://www.alejandroaravena.com/obras/vivienda-housing/elemental/
Permanent Structure: BASEMENT LEVEL A small section of the basement will be used by the public; but the majority of it will house reservoirs for hydraulic lift shafts and elecricity generators, as well as basins for the floating structures in the building.
fig. 33 circulation of public and private on basement level
fig. 34 key spaces on the basement level
fig. 33 - 34 Author’s own image 2011
Permanent Structure: GROUND FLOOR LEVEL The ground floor level will be where all the meetings are held. This floor will flood frequently with the tide; with ramps leading water into the building at strategic points.
fig. 35 circulation of public, guests and private
fig. 36 key spaces on the ground floor level
fig. 35 - 36 Author’s own image 2011
Permanent Structure: FIRST FLOOR LEVEL The first floor level will be maintained as a dry area void of water, where guests can escape to when the tide begins to rise on the ground floor.
fig. 37 circulation of public, guest and private
fig. 38 key spaces on first floor level
fig. 37 - 38 Author’s own image 2011
Permanent Structure: ROOF FLOOR LEVEL The roof will be used to harvest rainwater which will be used for recreational purposes; for this reason, the roof has to be accessible.
fig. 39 circulation of public, guests and private
fig. 40 key spaces on the roof level
fig. 39 - 40 Author’s own image 2011
Study: Venetian Construction Methods To ensure the survival of the permanent structure, I have had to study traditional Venetian construction techniques. These are well versed with the requirements for building in the Lagoon environment. The first important point to note is that all Venetian building construction should allow for movement and settlement20 due to exposure to damp; causing materials to expand and contract. Any structural system based on rigidity as apposed to elasticity will lead to cracking and failing21. High point loads and vaulted systems have therefore been avoided; opting instead for a lightweight superstructure of concrete, witha secondary structure of timber for upper floors.
fig. 42 Ancient foundation structures of St Alipio’s corner
20. Goy, J. Richard, Venetian Vernacular Architecture, Cambridge: Cambridge University Press 1989 p. 35
fig. 41 Fletcher, C.A, and Spenser, T., Flooding and Environmental Challenges for Venice and its Lagoon, Cambridge: Cambridge
21. Goy, J. Richard, Venetian Vernacular Architecture, Cambridge: Cambridge University Press 1989 p. 35
University Press 2005, p.175
Study: Foundations and Load Bearing Walls The foundations in traditional Venetian construction have always been built into the caranto clay stratum, which is a stable subsoil of clay under the lagoon; the bottom layer in fig.43. Timber piles were driven into this layer. The timber for these piles was very carefully chosen, either oak or larch, as they are both extremely durable. Larch was particularly perferred as it ‘not only preserved from decay and the worm by the great bitterness of the sap, but also it cannot be kindled with fire.’22
fig. 43 Section through the base of a wall in Campanile san Marco
The wood was then seasoned in sea water before being driven deep into the clay with an average of nine piles per square metre of floor area. When carrying large loads, the piles are kept close enough to form a virtually continuous wall four or rive rows deep. They are then leveled before a thick decking of timber planks known as zattaron is laid (fig.44). Non structural walls can be build directly from the zattaron layer, but main structural walls as in fig. 20 need several layers of damp proof istrian stone to raise the wall up to a level significantly higher than that of normal high tides. As Sansovino stated in Venetia Citta, these foundations would ‘last eternally’ if kept below water.23
fig. 44 section through the foundation to the colonnade of the Doge’s palace
22. Goy, J. Richard, Venetian Vernacular Architecture, Cambridge: Cambridge University Press 1989 p. 25
fig. 43 Giovanni Zocollo Il Restauro Statico Nell’Architecttura Di Venezia, Venice: Palazzo Loredan, 1975, p. 65
23. Goy, J. Richard, Venetian Vernacular Architecture, Cambridge: Cambridge University Press 1989 p. 38
fig. 44 Goy, J. Richard, Venetian Vernacular Architecture, Cambridge: Cambridge University Press 1989 p. 36
Falling Room The Falling Room is a guest bedroom which, during the course of the 5 years, will gradually drop 2.5m in height. The room, officially room 101, originally on the 1st floor, will eventually end up suspended just 57cm above ground floor level at the end of the 5 years. This will be acheived by wedging a sacrificial wall between a fixed, permanent wall structure, anchored into the ground on firm foundations. To ensure this strategy works, the materials have to be chosen very carefully, and their performance explored.
fig. 45 concept sketch ‘Falling Room’ 101
fig. 45 Author’s own image 2011
Foundations of Falling Room The two main walls in this short section are both permanent structures, but with the wall on the Western facade, there is a thick block of sacrificial material (5) in between the permanent concrete wall structure. The walls are anchored into the caranto layer with timber piles. The foundations are layered with damp proof Istrian stone at a height 80cm above sea level.
fig. 46 Short section through the falling room showing larch timber pile foundations
fig. 46 Author’s own image
Load Bearing Walls
fig. 47 Long section of building showing some of the main load bearing walls
fig. 47 Author’s own image
Study: Floors Floor construction in traditional Venetian architecture is predominantly beaten earth, brick or stone for the ground floors, which comes in regular contact with water. These materials would expand and contract regularly due to wetting and drying as well as temperature changes. So, for elasticity, a mixture of crushed bricks, lime and flakes of Istrian stone known as Terrazzo is the material of choice 23 (fig. 48). Spread over timber beams, it gives an even, smooth and polished finish. Although its weight does cause the timber beams to distort over time, the beams retain their structural integrity24.
fig. 48 detail of Terrazzo floor
The upper floors of Venetian buildings are usually of timber; with spans between floors being limited due to maximum length of beams of larch or aok available. These beams are ‘placed at close centres, the gaps between them being one or two and a half times the width of the beam giving the most evenly distributed load onto the wall. A wall plate took the load of these walls that were spiked to it, built into the brickwork’25 (fig.49).
fig. 49 section through typical floor detail in larger Venetian houses.
23. Goy, J. Richard, Venetian Vernacular Architecture, Cambridge: Cambridge University Press 1989 p. 43
fig. 48 image source: http://us.123rf.com/400wm/400/400/cheyennezj/cheyennezj0812/cheyennezj081200030/4015301-terrazzo-
24. Goy, J. Richard, Venetian Vernacular Architecture, Cambridge: Cambridge University Press 1989 p. 47
paving-venice.jpg
25. Goy, J. Richard, Venetian Vernacular Architecture, Cambridge: Cambridge University Press 1989 p. 48
fig. 49 Goy, J. Richard, Venetian Vernacular Architecture, Cambridge: Cambridge University Press 1989 p. 46
Permanent Floors
fig. 50 Long section of building showing fixed floors spanning between structural walls
fig. 50 Author’s own image 2011
Study: Roof construction Although most of the rooftops of Venice are clad in clay tiles, metal roofing was taken on in major public buildings, as well as the curved domes of churches such as St. Marco whose forms were difficult to finish in tiles. The use of copper is also prevelent in some public buildings26. The roofs are often constructed with a pitch, usually falling to a perimeter gutter. Rainwater was often collected and harvested by means of gutters. Taking from this, the construction of the roof is mainly in copper so that it is easily accessible by the guests; clay tiles will render the roof difficult to walk on. The roof will have to be sloped to allow water to run off into designated reservoirs and gutters.
fig. 51 Abbaino roof gable pitched to drain into eaves
fig. 52 rusting steel plated roof of St.Marco
26. Goy, J. Richard, Venetian Vernacular Architecture, Cambridge: Cambridge University Press 1989 p. 34
fig. 51 Goy, J. Richard, Venetian Vernacular Architecture, Cambridge: Cambridge University Press 1989 p. 55 fig. 52 image source: http://images.travelpod.com/users/mish_brendan/1.1302897455.saint-mark-s-cathedral-dome.jpg
Roof construction
fig. 53 Long section of building showing roof structure
fig. 53 Author’s own image 2011
Consultation: Rainwater Harvesting A conversation with Oliver Wilton, specialist in Environmental Technology, led me to consider the role of water within the building. He pointed out that saltwater and rainwater would be the two catagories of water that would interact with my building, and that traditionally, Venetians have had a different approach to dealing with them. Cisterns (fig.54), underground wells used to store and purity rainwater, are a common feature in Venice. This introduced a heirarchy of water, the purified rainwater being of most use to the Venetians. Initial ideas for how this could be applied to the roof structure of the building were discussed (fig.55).
3. 2.
1.
1. Sea water 2. Cistern 3. Sea water
However, seawater plays a more superior role in the building as it would be used to progress the architecture by means of floating and eroding. Rainwater cannot be purified to a standard suitable for modern health requirements, so it will be stored on the roof for recreational purposes, such as swimming, rather than drinking.
Fig. 54 initial ideas for roof structure
2. 3. 1.
4. 1. Salt water 2. Filtered water 3. Sand 4. Clay lining
Fig. 55 diagram of a Venetian cistern
fig. 54 Author’s own image 2011 fig. 55 Author’s own image 2011
Study: Venetian Water Harvesting System The lagoon water is essentially bitter seawater, and there are no rivers to take sweet water from. Rainwater was therefore essential to collect in order to satisfy the population’s needs. Water was collected by gutters of the durable and impervious Istrian stone27. In large houses the water was taken to the ground in vertical downward pipes which were built into the fabric of the external wall. In smaller cottages, rainwater was discharged into a public well-sump at the centre of a campo or cortile28. fig. 56 cross section sketch through typical Venetian well
Venetian wells are in fact large underground cisterns collecting rain water, situated in public squares (fig.56). A typical cistern is a large tank situated 5 or 6 meters deep in an excavation lined with a thick layer of impermeable clay to keep the water within the tank29. The well shaft at the centre is usually made of brick, stood on a large impermeable Istrian stone foundation slab. Small holes are left in the joints of the brickwork at the base of the shaft. The entire cistern is then filled with silt or river sand, filtering the collecting water. At the top surface, a caisson is built with openings to collect the rainwater30. The floor surface of the square is laid to lead water to these holes, harvesting water from the entire square and its pitched roofs.
27. Goy, J. Richard, Venetian Vernacular Architecture, Cambridge: Cambridge University Press 1989 p. 85 28. Goy, J. Richard, Venetian Vernacular Architecture, Cambridge: Cambridge University Press 1989 p. 85 29. Goy, J. Richard, Venetian Vernacular Architecture, Cambridge: Cambridge University Press 1989 p. 85 30. Goy, J. Richard, Venetian Vernacular Architecture, Cambridge: Cambridge University Press 1989 p. 85
fig. 56 Goy, J. Richard, Venetian Vernacular Architecture, Cambridge: Cambridge University Press 1989 p. 86
Precedents: Rainwater Harvesting The Sringaverapura temple in Allahbad (fig. 58) India was a source of inspiration for the form of the water harvesting tanks on the roof of the building. The elaborate staircases and purification system of the temple indicates a ritualistic relationship with water. As the water on the roof will be stored for recreational use, this seems appropriate.
fig. 37 shows the tanks of the temple which allowed water to flow in from the Ganges, through silt chambers and into ritual spaces used for ceremonies
fig. 58 Agarwal, Anil, and Narain, Sunita, Dying Wisdom, New Delhi: Centre for Science and Environment, 1997, p.16
Rainwater Harvesting Roof Through studying the above precedents, I have designed 3 reservoirs on roof of the Hotel to harvest rainwater. Though the precedents I have studied harvested the water for drinking, I propose to use it for recreational purposes on the roof, as well as for hydraulic lift shafts (a) and (b) positioned between the tanks. The water will move between these tanks and lift shafts between high and low tide with the use of floating walls, explored further in the next chapter. 1.
2. a.
3. b.
fig. 38 highlights the building’s rainwater harvesting reservoirs
fig. 59 author’s own image 2011
Falling Room: Gutters This diagram shows the course of the water through the drain built within the exterior wall of the Falling Room; taken from the drainage systems of large Venetian houses. Here, the gutters discharge into the canal, but through the sacrificial wall. As the water seeps through this wall, it will deteriorate it with time; gradually lowering the structure and altering the dimensions of the room.
fig. 60 cross section throough Falling Room 101 showing course of rainwater drained from the roof
fig. 60 author’s own image 2011
Water draining Like the squares and courtyards of Venice, there is a designed draining route built into the Hotel, draining the rooftop through basins which in some areas empty out into the canal, and in others collect the water for use in hydraulic lift shafts.
fig. 61 Long section of building showing run off points of water from roof into basins that drain into the canal
fig. 61 Author’s own image 2011
CHAPTER 4 ‘Bad design’ - Floating structures Elements rise and fall, reacting to the fluctuating tide.
Precedent: Floating Houses (IJburg) Architectenbureau Marlies Rohmer The floating houses designed in the Netherlands were an initial inspiration that lead me towards thinking of structures that were gradually raised and dropped with the tide. The construction methods used by Marlies Rohmer were of two kinds. Either a foam block was incased in concrete, allowing it to float, or a hollow concrete shell was used as a buoyant raft31. This hollow shell is inhabitable and half submerged. The concrete used is marine grade; poured in one mass to ensure structural integrity32. The mould is supported by a reinforced steel mesh (fig.63). Once the concrete has cured, the shuttering is removed in order to mark out the lower ground floor layout, which is submerged two thirds of its height below the water33 (fig.64).
fig. 62 photograph of Floating Houses in IJburg, Architectenbureau Marlies Rohmer
fig.63 shows the mould for the concrete constructed in a factory dock for ship building
fig. 64 shows the base layout for ground floor on cured concrete base
31. http://www.architecturetoday.co.uk/?p=12288
fig. 62 http://www.archdaily.com/120238/floating-houses-in-ijburg-architectenbureau-marlies-rohmer/
32. http://www.bowcrest.com/dutch-barge-specialists/
fig. 63 http://www.bowcrest.com/dutch-barge-specialists/index.php/floating-homes/how-your-new-floating-home-starts-life/
33. http://www.bowcrest.com/dutch-barge-specialists/index
fig. 64 http://www.bowcrest.com/dutch-barge-specialists/index.php/floating-homes/how-your-new-floating-home-starts-life-2/
Consultation: Floating Structure A consultation with Ed Clark, a civil engineer specialist at Arup helped me understand the mechanism of causing a building to float. He explained the phenomenon of materials rising when built close to water is known as ‘uplift’. Buildings are often weighed down to ensure there is minimal uplift. In multiple floor buildings, this is taken care of by the weight of the floors. Structurally light buildings (such as mine, only 3 stories high) either anchor themselves with piles (fig.65) into the ground or rely on extremely heavy foundations. This discussion lead me to consider the parts of the building that would be allowed to ‘float’ between the anchored foundations, allowing for buoyancy without inducing structural failure.
fig. 65 diagram illustrating affect of uplift on a building
fig. 65 Author’s own image 2011
Floating Walls at High Tide
fig. 66 Long section showing floating walls within the building fluctuating with the 5 main measurements of tide
fig. 66 Author’s own image 2011
Floating Wall Detail The diagram on the right depicts the basic structure of the floating wall; a hollow concrete shell constructed in a manner similar to that of the Floating House rafts. This wall ‘raft’ will be attached to a concrete basin built into the ground floor, lined with runners to allow the wall to rise and fall with the tide. The basin is connected to the water level of the adjacent canal through a ramp, designed to bring water and debris in and out of the basin with the tide. Debris will build up as the floating wall knocks against a shock-absorbing block of stone above it, designed to take impact every time the wall rises with the tide. For this process within the building to be understood correctly, it is fundamental to investigate the impact the movement of this floating wall will have on the materials used for the basin and the wall itself, as it will be subject to damage rising and falling with the tide at a range of up to 0cm to +194cm on a daily basis for four years.
1. floating hollow concrete wall 2. runners lining basin
3. concrete basin flooded at high tide 4. ramp leading into canal fig. 67 diagram of floating wall structure within concrete basin
fig. 67 Author’s own image 2011
Materials for Floating Structures Marine grade concrete is often used in boat building, bridges and wharves. It is ideal for its lightweight buoyant quality. The concrete itself is dense and of low permeability grade 3034. The low permeability is acheived with a minimum cement content of 300kg/m3 (fig. 68). Even with a low permeability, in the presence of sea water a mix of concrete with only a 5-8% content of tri-calcium aluminate is required. This is because the soluble chloride ions in salt water react with calcium hydroxide and tri-calcium aluminate (C3A) to produce gypsum and calcium sulphate aluminate. These particles occupy more volume, causing the concrete to expand and crack, exposing the reinforced steel to corrosion. The chloride ions do however eventually reach the reinforced steel, and once this occurs in a sufficient content, the steel rusts, weakens and causes catastrophic failure in the structure35. To prevent structural failure from occuring for at least 50 years, the concrete ‘cover’ above the reinforced steel has to be at least 40mm thick. The Venetian answer to this problem has always been using a sacrificial layer of plaster to prevent structural material from deteriorating. This is why render in Venetian buildings has always been of paramount importance. The render applied to this structure will be explored further in chapter 5. 34. PC Varghese, Advanced Reinforced Concrete Design 2nd ed, New Dheli: Prentice-Hall, p.441 35. Wake, Hastie and McDonald, Estimated Lifetime of Marine Concrete, C411
fig. 68 diagram of floating wall structure within concrete basin
fig. 68 PC Varghese, Advanced Reinforced Concrete Design 2nd ed, New Dheli: Prentice-Hall, 2006 p.441
Floating Wall Detail: Materiality This cross section shows the marine concrete basin, floating wall and their relationship with the canal. The tide levels have been marked. The sacrificial 750mm of concrete is added to the structure up to a height of +200cm; which is the maximum height of high tide.
40mm protective concrete ‘cover’ over reinforced steel Water from tide enters and leaves through metal mesh panel
reinforced steel frame
hollow concrete wall
marine concrete basin
fig. 69 cross section of floating wall in basin facing tributary canal
fig. 69 Author’s own image 2011
Floating Floor Detail The diagram on the right depicts the floating floor of the main Conference Room, which is similar in construction and materiality as the floating wall. The Floating floor will be occupied by a conference of up to 32 delegates; and the concrete will have to remain buoyant for the duration of the conference. As the construction of the floor is similar to that of a raft on a boat, there will be some instability as the water rises and falls. The delegates will experience a level of discomfort, however the movement of the floor will be restricted by the runners that secure the rising floor within its basin.
hollow concrete floor raft runners concrete basin
fig. 70 long sectional diagram of floating floor structure within concrete basin
fig. 70 Author’s own image 2011
Model : Conference room
+80cm
These photographs show the height to which the floating floors are expected to rise at high tide, given the weight of the marine grade concrete and the respective heights of tide. This is however a speculation, and further testing will have to be done with addition of the weights of furniture and occupants to determine the extent to which the floor will rise once it is occupied. +109cm
+140cm
+194cm Fig. 71 shows the rising rising floor and wall of the conference room at 4 different levels of high tide
fig. 71 Author’s own image 2011
Detail: Reservoir Walls, Roof Level Four of the walls acting on the reservoirs of the roof will be floating walls. Their rising and falling will change where the water collects; as they are positioned between the reservoirs on the roof (where water is used for recreation) and the basement (where water is used for the hydraulic lift shafts). This section relays the strategy for the rising reservoir walls; constructed in the same method as previously outlined.
hinged joint clipped to canvas fixed to rising wall
canvas wall
Floating wall
These walls have a hinge joint at the top, which clips onto a canvas material. This canvas material is waterproof, and is secured at the other end to the reservoir floor. As the tide rises, the wall raises the canvas and stops water from the roof spilling into the hydraulic lift shafts at the basement level of the building, which would already be accumilating with water at high tide. At low tide, the walls lower themselves and water is allowed to collect in hydraulic lift shafts.
Concrete basin
fig.72 section through lift shaft a. and reservoir walls showing rainwater harvesting strategy
fig.72 author’s own image 2011
Detail: Rising reservoir walls This section (fig. 73) shows the gradual rise of the canvas wall with the tide. In Venice, the highest amount of rainfall (88mm in November) is in the winter months (fig.74), which correlates with the highest tides. In theory, this will allow the most rainwater to be harvested on the roof during the winter periods, where tides will reach their highest and allow the canvas walls rise by an average of 1.4m, creating a basin to accumilate the water until low tide, when it will drop into the hydraulic lift shaft basin.
fig. 74 annual rainfall Venice
fig.73 section through lift shaft a. and reservoir walls showing rainwater harvesting strategy
fig.73 author’s own image 2011 fig.74 http://www.wordtravels.com/Cities/Italy/Venice/Climate
CHAPTER 5 ‘Bad design’ - Eroding structures Sacrificial elements dissappear with the tide
Precedent: Venetian Renders The exterior walls of Venetian buildings have always been very thin in order to minimise the load they exert on their foundations. For this reason, plasterwork in Venice has a protective role; acting as a sacrificial layer that is allowed to erode with the tide in order to prevent the structural walls from deminishing. As these walls are already so thin, a decrease in their cross-section would lead to structural disruptions36. Thus, besides their aesthetic and formal qualities, E. Danzi et al argue that the primary purpose of Venetian plasterwork has always been to prevent masonry decay from occuring in structural load baring walls37. This plasterwork is gradually worn away by weathering, saline aerosols and capillary rise. Venetian renders led me to think about structures in my building which would be designed to erode; their gradual wearing away revealing new uses for the spaces changed by the tide. This chapter investigates the eroding structure strategy by exploring in detail the two sacrificial materials in the building; wood and rammed earth. Both have been tested to understand how the materials would behave in response to the tide and its water composition.
fig.74 Eroded Regalzier plaster applied over masonry brickwork; Regalzier is a stabiliture plaster often applied with monochrome paint
36. Fletcher, C.A, and Spenser, T., Flooding and Environmental Challenges for Venice and its Lagoon, Cambridge: Cambridge Univer-
fig.74 Fletcher, C.A, and Spenser, T., Flooding and Environmental Challenges for Venice and its Lagoon, Cambridge: Cambridge
sity Press 2005, p.194
University Press 2005, p.195
37. 23. Fletcher, C.A, and Spenser, T., Flooding and Environmental Challenges for Venice and its Lagoon, Cambridge: Cambridge University Press 2005, p.194
Precedent: Rock Pools The rock pools in Lido inspired me to consider the ways in which the tide bringing in and taking away debris can completely transform a space. These stills from a short recording I made show the phenomenon of a sudden wave flushing the pool with sand; leaving the space between the rocks transformed. The large rocks themselves have also been transformed with the contact of sea water; with traces of algae marking the levels of the tide.
fig. 75 shows stills from a short film I recorded of a rock pool filling up with the tide
fig. 75 Author’s own image 2011
Precedent: Materials Reacting to Seawater These observations of the way materials change, leak, mark and imprint their presence on eachother in response to the Adriatic seawater led me to consider the gradual change of materiality in the Hotel. The tide levels are marked on the stairs in the canals by algae (fig.76), and copper plates rust, forming copper sulphar dioxide when in contact with the salts in seawater. This stains the stone they are in contact with (fig.77). The colour of the Istrian stone gradually wears to black as calcite turns to calcium sulphate (chalk) and is washed away; even though the porosity of the stone is only 0.5% (fig.78)
fig.76 copper turning to copper sulphar dioxide
fig.77 calcite in Istrian stone turning to calcium sulphate
fig.78 algae marking tidal level by colouring stairs of the canal
fig. 76 - 77 Author’s own image 2011 fig. 78 image source: http://triptovenice.webs.com/venicerestaurant.jpg
Falling Room: Sacrificial Material The sacrificial layer (fig.79, no.6) in the Falling Room will gradually deteriorate over 5 years to allow the floor of guest room 101 to drop by 2.5m. For this to occur, a block of sacrificial material, 2.5mx1m will be placed between the non-sacrificial concrete load bearing wall. A gap in the exterior wall will allow the tide to flush the sacrificial wall; a sloped ramp deposits the debris from the wall into the canal. The material for the wall had to be considered very carefully; as I wanted it to fall gradually under the weight of the structure above and to the exposure of the tide. My initial thoughts were to use an elastic lime based plaster; as with the plasters used for renders on Venetian buildings. I decided to discuss this with a materials specialist consultant from Arup to ensure I was making the right decision.
fig.79 short section through Falling Room indicating plaster as the material for the sacrificial wall
fig.79 author’s own image 2011
Consultation: Material Choice Richard Hughes, an experienced conservator, gave a great deal of insight into the choice of material for the sacrificial wall. His comments made me realise that this was a vital decision to make, as it would result in the mechanism either working or failing. He informed me that plaster, which was what I planned on using, is quite brittle. Given the weight of the structure ‘falling’ or collapsing down onto the crumbling sacrificial wall, the brittleness of the plaster means it will at some point fail. This will result in a slow falling, and then a sudden collapse where the wall will want to fall sideways in one instance. Earth or clay however, is a softer and less brittle material, which will continue to erode slowly from top down, responding to the weight of the structure above it. The wall will in affect be ‘squashed’. Also, clays are materials that form a much shallower natural angle of repose. This is the angle left behind by the residual lump of debris that will form due to the eroding. As a result, a shallower angle means the erosion will gently slope towards the ramp and into the canal, rather than gather in a bulge like form. fig.80 sketches made during consultation with Richard Hughes
fig.80 Author’s own image 2011
The discussion I had with Richard Hughes led me to consider rammed earth as a material for the sacrificial wall (fig.81). It was then imperative that the mix was such that it would erode at the right rate with the tide as well as the weight of the structure above it. To make sure the mix was correct, I decided to build the wall at a scale of 1:5 to gain an understanding of the material.
fig.81 short section through Falling Room indicating plaster as the material for the sacrificial wall
fig.81 author’s own image 2011
Experiment : 1:50 Rammed Earth Construction The method of constructing the sacrificial rammed earth wall at a scale of 1:5 was as follows; once the earth had been packed into an mdf mould lined with latex, it was covered with a lid (fig.46). The mould was then secured to a bottle jack; the jack’s head carefully aligned to the centre of the steel plate attached to the lid. This was in order to ensure pressure would spread evenly throughout the wall (fig.47). The jack and mould were held between two verticle walls. Once the earth had been rammed by a few centimetres, the pressure began to break the mould, so it had to be secured with rope (fig. 48). The earth was rammed until the pressure began to deform the steel beams holding it in place (fig.49).
fig.82 mould
fig.83 mould secured to jack between wall and extractor foundation
fig.84 rope used to secure mould
fig.82-85 author’s own image 2011
fig.85 pressure caused by ramming jack
Experiment : Results I tried three mixes of different ratios. The first was a clay loam mixture; with 30% clay and 70% sand (fig.49). Second was a clay loam mixture with some portland cement, as the first attempt seemed too soft and wet. This was 30% clay, 65% sand and 5% cement. This mixture fell apart the moment it was taken out of the mould as it was too dry (fig.50). The final mixture was 10% clay and 90% sand, to try to make a firmer wall without adding cement (fig.51). The 2 successful walls were left to dry for one day before being moved. After drying, the clay loam wall became a lot harder, whereas the sandy loam wall broke as soon as it was moved (fig.52). This lead me to conclude that the first mix was the closest to a consistency that would work.
fig.86 clay loam mix
fig.87 clay with cement; failed mix
fig.88 sandy loam mix
fig.89 successful walls after 24H drying period; clay loam hardened whereas sandy loam crumbled
fig.86-89 author’s own image 2011
Sacrificial Wall - Rate of Attrition The study taken on by Biscontin, Zendri and Bakolas on the rate of attrition in brickwork when exposed to Venetian sea tides38 is a useful starting point for assuming the rate of attrition of my rammed earth wall. Although the materials eroding are not the same, Biscontin et al describe in particular the rate at which silicon oxide (sand) disappears from the clay; sand also forms 70% of my rammed earth wall. The cumulative volume of the brick sample at depths ranging from 0-5.5cm has been measured. The cumulative volume in each sample is highest at 0cm, and the % of Silicon oxide is lowest; implying the most amount of silicon oxide is washed away at the facade facing the tide, leaving behind a more porous brick. fig. 90 Table illustrating depth profile of total silica and cumulative volume of 4 brick samples reacting to Venetian sea tide
38. Fletcher, C.A, and Spenser, T., Flooding and Environmental Challenges for Venice and its Lagoon, Cambridge: Cambridge Univer-
fig.90 Fletcher, C.A, and Spenser, T., Flooding and Environmental Challenges for Venice and its Lagoon, Cambridge: Cambridge
sity Press 2005, p.199
University Press 2005, p.201
Sacrificial Wall - Factors for Measuring Attrition Hughes informed me that salt efflorescence will be the major factor that will cause the sacrificial wall to deteriorate. Microwind movement, tidal temperature, humidity and capillary rise (which occurs 2-3m above sea level) are the main contributing factors to the formation of salt crystals. Add to this, in the case of the Falling Room, the weight of the concrete structure ontop of the sacrificial wall will also contribute towards its deterioration. Fig.91 demonstrates these factors acting on the rammed earth wall. 1) Weight: the weight of the concrete structure, a lightweight concrete wall 3.3m in height, is estimated at around 62kN. This will bear down on the rammed earth wall. 2) Temperature: the sun will not directly heat the wall as it is only exposed on the west facade, on which side the Hilton Molino, 35m in height, blocks light. The sun will directly heat the concrete structure above the wall for a period of around 4 hours a day. 3) Capillary rise: this is estimated at around 2-3m above sea level. This means the wall will not be exposed to a continuous wetting and drying; as the water will constantly keep it wet. This will reduce the speed of the attrition process as temperature will be more constant if the wall isn’t exposed to cycles of wetting and drying. However, given that changing factors of tidal temperature and microwind movement involved, this is only a rough estimation of the erosion of the rammed earth wall. over the course of the 5 years, these factors are liable to change, therefore altering the rate of erosion.
fig.91 short section of the Falling Room shows the rammed earth wall exposed to factors contributing to attrition
fig.91 Author’s own image 2011
Expanding Joints The shock absorbing concrete blocks situated above the floating walls are not connected to the floors. This is because the damage that will occur to them will render them too weak to bear a structural load. Instead, a gap of 200mm between the floor and the shock absorbing stone has been left to allow for movement. These impact blocks will be rendered with small holes to allow water from the 1st floor and ceiling to flow through them and into the basin directly underneath. For this reason, the gaps betwene floor and stone have to be filled to allow water to flow continuously. The 200mm gap is therefore filled with wood (fig.92, a & b), which will expand when exposed to water, closing the gap, allowing water to flow directly over and into the basin underneath.
fig.92 section indicating position of expanding wooden joints on either side of concrete shock absorbing block
fig.92 Author’s Own Image 2011
Experiment: Expanding Wood in Saline and Non-Saline water I tested the expansion and material reaction of three different samples of timber; english elm, brazilian mahogany and tanalized oak, in saline and non-saline water. The aim of this test was understand the amount of expansion, as well as the affect of salt crystalisation on the material, the change in their visual appearance and if they would stain the concrete blocks they are connected to. Mahogany and elm are both hardwoods chosen for their colour, and tanalized aok is a softwood treated to be waterproof, hence minimal reaction to water is expected.
fig. 93 Elm, tanalized aok and brazilian mahogany to be tested
fig.93 Author’s own image 2011
Experiment: Results of Colouration After a 5 day period, the brazilian mahogany lost the most amount of colour. The colour started to leak from the wood faster in saline water.
non- saline
saline
fig.94 first suberged in water at room temperature
non- saline
saline
fig.95 5 days later
saline
non- saline
fig.96 colour is darker in saline water
fig.94-96 Author’s own image 2011
Day 1
Day 5
Day 7
Experiment: Results of Salt Crystal Formation After a 5 day period, salt crystals began to form on the mahogany and elm wood. The crystals formed on the dry surface of the wood exposed to air. By the end of the 7 days, the salts covering each would were of slightly different appearance. The brazilian mahogany coloured the salt that formed on it; whereas tanalized oak produced the whitest salts.
Elm
Tanalized
Mahogany
fig.97 Study of salt crystal formation on elm, tanalized aok and brazilian mahogany submerged in salt water over a period of 7 days
fig.97 Author’s own image 2011
saline
saline
saline
Experiment: Expanding Volume The size of the three different woods altered in both solutions, but more so in salinated water, as can be seen from fig.98. The samples were measured over a period of 9 hours with calipers to the 0.00 mm. The tanalized oak expanded a lot more rapidly in saline water than nonsaline. As it is a softwood, this was expected. The elm expanded at a more or less constant rate in both saline and non-saline solutions. The mahogany expanded slightly less in saline water than in non-saline water; which was an interesting result. This does however need to be thoroughly tested over a longer period of time in order to be varified.
Elm
Oak
Mahogany
fig.98 graph showing the gradual increase in volume of oak, elm and mahogany in saline and non-saline solution over a period of 9H (full data in appendix)
fig.99 graph showing the gradual increase in volume of oak, elm and mahogany in saline and non-saline solution over a period of 9H (full data in appendix)
fig.98-99 Author’s own image 2011
For the colour it deposits in salt water, brazilian mahogany has been chosen for the joints. It expands at a rate of roughly 0.32mm every 24 hours. These images show the gradual build up of colour in the concrete stone from the mahogany joints once they’ve been washed with sea water over a 7 day period. The joints will gradually expand and salts crystallize between the 5th and 7th day. Day 1
Day 5
Day 7 fig. 100 Section of mahogany wooden joints and concrete block over 7 days of exposure to water
fig. 100 Author’s own image 2011
Conclusion The testing, research and design development undertaken in the course of this study has been neccessary to understand the impact of the tide on the architecture of this project. However, given the fluctuating nature of the factors involved that impact the three different strategies, it can only be said with confidence that the first stategy would perform as intended. This is due to the fact that the strategy of the permanent structure has been evolved with an understanding of conventional practice. However, with regards to unconventional methods applied, the environmental factors affecting them will vary gradually over the 5 years, especially once the building is occupied. It cannot therefore be said with accuracy what the implications of temperature changes, humidity changes or high tide changes will be. An attempt has been made, however, to engage these changes with the building to produce a spatial outcome. Major structural errors have been avoided on account of consultations with experts. Although this study has not produced results that are fully tangible, the design has been enriched by investigating the potential outcomes of the materials used with regards to eroding and buoyancy. Establishing the materiality of the Falling Room helped to understand the nature of materials as they erode and wear away; enriching the design as apposed to limiting it. This report has helped towards forming a vital understanding of the inevitable processes the building will be exposed to over 5 years; and although the engagement with these factors has been superficial, an awareness of them has been vital to progress the design of this project.
APPENDIX Basement plan Ground floor plan 1st floor plan Roof plan Long section Long section year 1 Long section year 5
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