Home Infrastructure Architecture articles A New Paradigm in Designing Sustainable Floating Architecture- Part I

A New Paradigm in Designing Sustainable Floating Architecture- Part I

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Floating architecture can be defined as a building for living/working space that floats on water with floatation system, is moored in a permanent location, does not include a watercraft designed or intended for navigation, and has a premises service system (electricity, water/sewage and city gas) served through connection by permanent supply/return lines between floating building and land, or has self-supporting service facilities for itself. Floating architecture on water has been emerging as a sustainable alternative around the waterside region, and floating architecture can be regarded as one of the most sustainable building types if proper sustainable factors would be applied.

Floating architecture is gaining significance in the wake of increasing public awareness for new development of waterfront areas. Rehabilitation of Brownfield’s, particularly those of former lignite mine pits, is an expensive undertaking and requires not only technical solutions but the generation and involvement of new ideas. Floating architecture is a possibility for redevelopment after the closure of open cast lignite mines. It can give impulses for regional development instead of pure rehabilitation of a culture landscape. Moreover, it offers opportunities for the renewable energy source water. Yet, there are a lot of additional problems due to the special climate boundary conditions including wind waves and chemical components of water in case of post-mining lakes. There is a need for studying and solving these problems to avoid damage in future.

Floating architecture could be a resolution in future for current problems in many districts, cities and landscapes. Such problems can be seen especially in the need of additional housing areas and construction grounds in some countries in Europe and Asia as a result of the growing population and/or the slowly rising sea level in the context of the worldwide climate change. Another example of problems of current interest is the use of alternative sources of energies. The water areas of channels and closed down harbours offer good opportunities to create new water landscapes with modern marinas consisting of floating houses and other floating architecture.

Currently, living on the water is a niche market and is not considered equivalent to a house built on land by the majority of the population in the United States. But with an ever-growing population that tends to migrate towards the water and the gradual rise in sea level, urban areas must consider expanding new development on the water. Not only have water dwellings proven efficient in times of extreme flooding, but the cost of building and living in a water dwelling can be significantly less than a house built on the land.

Today, waterfront cities are beginning to recognize the negative consequences of such a massive population movement into urban areas. In order to deal with the growing density of these urban metropolises, the natural instinct is to build up and in, creating a much more dense area within their city boundaries. However, urban sprawl has led to cities branching out in all directions to accommodate the growing population migration. With the majority of the world’s most populated mega-cities are located along the coasts and the growing concern over the inevitable rise of ocean sea levels, a new typology for mitigating urban congestion must be considered, such as building on water.

The paper attempts to discuss at length some of the recent innovations in designing and developments of sustainable floating architecture that can be used as replicable models in several parts of the world.

Types of Floating Architecture

Houseboats

Houseboats began with the conversion of ships and fishing vessels into livable environments (Figure 1). These types of houses resemble a land based property in its design and construction yet are buoyant enough to withstand the forces of water. The dwellings have been a part of American history since the early 1900s where the earliest houseboats in Seattle were recorded in 1905, and peaked with over 2,000 houseboats in the 1930s. During the 1940s, World War II brought much activity to the shores of California as shipbuilders and factory workers were transported to San Francisco. The need for housing brought many workers to transform old fishing boats and decommissioned war surplus into residential dwellings in Sausalito Bay.

 

Floating architecture

 

Some of the more modern examples of floating homes are those built by Dutch architects including Waterstudio.nl, Aquatecture, Factor Architecten and Architectenbureau Marlies Rohmer. The trend to build residences on water has enticed many homebuyers in coastal countries in Europe however it has yet to fully catch on in the United States.

Floating Houses

Floating architecture is gaining significance in the wake of increasing public awareness for new development of waterfront areas. Rehabilitation of brownfields, particularly those of former lignite mine pits, is an expensive undertaking and requires not only technical solutions but the generation and involvement of new ideas. Floating architecture is a possibility for redevelopment after the closure of open cast lignite mines. It can give impulses for regional development instead of pure rehabilitation of a culture landscape. Moreover, it offers opportunities for the renewable energy source water. Yet there are a lot of additional problems due to the special climate boundary conditions including wind waves and chemical components of water in case of post-mining lakes. There is a need for studying and solving these problems to avoid damage in future.

The harmonisation between architecture and nature needs to be seriously thought about designing and constructing floating houses. Moreover, there are questions about energy and quality water supply. The managing of waste disposal must be resolved. In districts with cold wintertime the attacks of ice to the pontoons and the safety of walking on footbridges must be considered.

Floating architecture could be a resolution in future for current problems in many districts, cities and landscapes. Such problems can be seen especially in the need of additional housing areas and construction grounds in some countries in Europe and Asia as a result of the growing population and/or the slowly rising sea level in the context of the worldwide climate change. Another example of problems of current interest is the use of alternative sources of energies. The water areas of channels and closed down harbours offer good opportunities to create new water landscapes with modern marinas consisting of floating houses and other floating architecture.

Amphibious Dwellings

Amphibious housing is a dwelling type that sits on land but is capable of floating. (Figure 2) During a sudden rise in water, a house will be lifted by the water, provided either by pontoons or a hollow basement, in order to ensure it remains dry, and will then return to the ground as the water recedes. By sliding along two vertical mooring poles that are driven deep into the ground, the houses are capable of rising vertically while restricting horizontal movements on the water.

 

 

Although the amphibious house resembles a houseboat, there are some essential differences between the two types. The hollow basement of an amphibious house is exposed when there is no water, forcing designers to conceal the base in the ground or in water. The second difference is the distribution of forces in the base. When the property is sitting on land it lacks the even upward force of the water which it experiences when it floats, making the basement larger than that of the barge of a houseboat. The biggest difference between houseboats and amphibious homes is their connection to the land. Typically, amphibious homes are designed where water levels are moderate but are rarely prone to extreme flooding; therefore all utility services can be connected to the municipal pipes whereas houseboats must contain all utilities within the structure. Examples of these houses can be found throughout the Netherlands, most notably the Maasbommel water dwelling situated along the River Maas. A list of the advantages and disadvantages of each type of water dwelling can be found in Table 1.

The buildings and places that we create in the next ten years will form the backbone of an amphibious lifestyle for the next five decades and beyond. In order to prepare for the future, designers and builders must not look at the limitations of water, but at the opportunities it presents.

Floating Building and New Paradigm of Architecture

According to the British Columbia Float Home Standards (http://www.housing.gov.bc.ca/pub/htmldocs/floathome.htm),
float home means a structure incorporating a floatation system, intended for use or being used or occupied for residential purposes, containing one dwelling unit only, not primarily intended for, or usable in navigation and does not include a water craft designed or intended for navigation. The new paradigm of architecture can be described as a new model and/or system of architecture with the new concept and Zeitgeist like sustainability.

Sample Floating Buildings: Case Studies

IBA Dock, Hamburg

This building was designed by Prof. Han Slawik, Hannover, was the headquarters of the IBA Hamburg GmbH as well as an information and event center for the IBA (Figure 3). It was centrally located and provided easy access for the visitors to IBA. Now the building is being used for Urban and Architecture information center in Hamburg.

 

 

This is a steel-constructed floating building with the concrete pontoon. The superstructures were made in a modular construction and assembled on the pontoon. It also used a ready-made heating and cooling ceiling elements in the entire building. Multiple possibilities were reviewed to provide energy supply for the IBA Dock from the water temperatures of the Elbe, solar heat panel, and solar photovoltaic cells.

Floating Hotel “Salt & Sill”, Sweden

This floating hotel was designed by Mats & Arne Architects, Sweden, opened alongside the famous seafood restaurant “Salt & Sill”(Figure 3). The hotel consists of six two-story wooden buildings on the concrete pontoon. All the rooms have their own entrance and access to the outdoor seating area. The hotel is very popular even though it is located in the rural & coastal area. So there are many visitors all the year over. The design of the hotel was done with the environment sustainability in mind as heating energy is actually generated from the warm sea water underneath the hotel in winter. The building used local raw materials such as the wood from Swedish pine forests, and environmentally friendly paint. And they have even used the leftover the quarrying stone to build a new lobster reef under the pontoon. As a result, the sea life was positively increased.

 

 

Oregon Yacht Club, Portland

The Oregon yacht club (OYC) is a floating home community located on the Willamette River in Portland, Oregon. It is close to downtown with a pastoral setting, so became one of the premier floating home moorage.

The OYC has more than 100 years’ history. The original purpose was to foster and encourage yachting and to promote/increase the efficiency of its members in the science of navigation and the art of handling/sailing yacht. After 1910, OYC started allowing houseboat living in summer, eventually evolved to the year-round homes of today. OYC is now a modern houseboat community, with a predominance of two-story buildings replacing the traditional one-story residences. The club is currently comprised of 38 floating homes that are permanently situated on the moorage and the walkway. OYC members have an annual inspection of houseboats to make sure they are in the shipshape and striking display as and when to be inhabited. The community has great interesting in conserving the natural environment like the restoration of wild birds, clean marine programme, watershed re-vegetation program, and others.

Floating Cemetery, Hong Kong

This floating cemetery was designed by Tin Shun But, gives a totally new concept of burial at sea (Figure 5). It is really difficult to find a place in Hong Kong for the cemetery. As burial grounds are very limited, private cemetery space is extremely expensive and there is a long waiting list for the public burial site. So the majority of dead bodies are cremated. According to Buddhist tradition, people wants to provide good resting places for dead ancestors. There are some debates whether to build a multi-story columbarium or develop the land for the cemetery. So the architect proposed a floating cemetery near harbor. Visitors can go to the columbarium by boat and keep the ashes in a designated niche or scatter them over the sea. There should be a quite different atmosphere comparing with the existing cemetery on the land. This structure can be a sort of artificial park and provide good seascape to the prayers.

Floating Pool, Prague

This floating circular pool project was designed by the Czech architect team of Ondrej Lipensky and Andrea Kubna, came with the idea to clean the polluted river water and also to offer the recreational facility for the residents (Figure 6). The historic Vltava was a popular swimming and skating place before industrialization. The circular pool structure will function like a giant floating strainer to filter its contaminated water, so that the residents can swim and skate there as before. The architects proposed to create several floating recreational islands with the purifying facility of the textile membrane. Users can access by boat and/or floating pedestrian bridge.

 

The pool is located in the center of the structure and is surrounded by a bar, private cabins, changing rooms, restrooms, shower & sauna rooms, and mechanical room. A smaller and shallower pool is also provided for younger kids. The river water can be filtered through a textile membrane on the bottom of the pool. This filter can make the water of the pool cleaner for guests and also improve the quality of the river water. In the winter, the pool can be converted into an ice rink for continued use all the year round.

Floating Offshore Stadium, Qatar

This stadium was developed by the German architects “Stadium concept” for the FIFA World Cup 2022 (Figure 7). The floating offshore stadium can be relocated to seaside place across the oceans. Therefore this stadium can be used by more effectively than the usual on-shore stadium.

 

 

 

The stadium can be eco-friendly powered by renewable energy resources such as water, the wind and solar power. As floating structures are located in seaside and there is no obstacles, the wind and solar power is easy to obtain.

Its global mobility, long-term utilization and various economic efficiency show great advantages and so can be a new model for 21st-century sports facility. Once a big sports event such as World Cup or Olympic Games was completed, operation and maintenance of the stadium raise economic problems due to low utilization. To compensate the economic weakness, other sports, rock concerts and public event are to be considered.

Almost all the countries of the world have access to the sea. This unique floating stadium can be one of the most innovative and sustainable facilities worldwide due to economic efficiency and long-term utilization.

Floating Pavilion with Adjoining Platform, Rotterdam

Commissioned by the Municipality of Rotterdam, Dura Vermeer has constructed a new floating icon in the Rijnhaven in Rotterdam (Figure 8). The Floating Pavilion is the first result booked by Rotterdam Climate Proof (part of the Rotterdam Climate Initiative) in a series of projects involving climate proof construction in areas outside the Netherlands’ system of protective dykes. The pavilion also unifies the objectives of the city of Rotterdam to half emissions of greenhouse gasses such as CO2 and to keep the city climate proof in the future. Futuristic image The Floating Pavilion was designed by Deltasync/Public Domain Architects and consists of three linked dome constructions with diameters of 18½, 20 and 24 metres respectively and a height of approximately 12 metres. The total floor area is 46 by 24 metres. The pavilion is connected to a floating platform that is joined to the quayside by two bridges.

 

 

Floating Theatre at Spree River in Berlin

Russian architect Alexander Remizov considers that a floating building could be a model of life in the future. Remizov called his prototype “The Ark” (Figure 9) is made of wood, steel and strong ETFE plastic and could be adapted to many different environments. Ark could be used for various purposes, including accommodation in an emergency and as a hotel. Remizov argues that “the structure allows rapid construction of the facility that may be floating”. The author of the project solved the problem of the power supply by placing a generator of electricity using wind power in the center of the building. Moreover, the facility is on the outside covered with solar panels. If the building is set on the water, Remizov claims that “it could use the thermal energy of water. However, it has been not explained exactly how that would be achieved. Although it is a prototype, Remizov believes that Ark could be used for various purposes, from apartments and offices to auditoriums, conference halls and hotels.

 

 

Floating Sauna, Norway

Floating Sauna has been designed by Casagrande & Rintala for the Rosendahl village by the Hardangerfjord in Norway (Figure 10). The sauna is situated in the center of the village. It glows like a lantern when the sauna is in use. “The Design-Build process was an intensive workshop for the Västlands Art Academy, Norway”.

 

 

Sustainability and Floating Architecture

Sustainability is the capacity to endure. For humans, sustainability is the potential for long-term maintenance of well being, which has environmental, economic, and social dimensions. According to the Brundtland Commission of the United Nations on March 20, 1987, sustainable development is a development that meets the needs of the present without compromising the ability of future generations to meet their own needs. A universally accepted definition of sustainability is elusive because it is expected to achieve many things. On the one hand it needs to be factual and scientific, a clear statement of a specific “destination”. The simple definition “sustainability is improving the quality of human life while living within the carrying capacity of supporting eco-systems”, though vague, conveys the idea of sustainability having quantifiable limits 1. Sustainable architecture is a general term that describes environmentally conscious design techniques in the field of architecture. Sustainable architecture is framed by the larger discussion of sustainability and the pressing economic and political issues of our world. In the broad context, sustainable architecture seeks to minimize the negative environmental impact of buildings by enhancing efficiency and moderation in the use of materials, energy, and development space. Most simply, the idea of sustainability, or ecological design, is to ensure that our actions and decisions today do not inhibit the opportunities of future generations. This term can be used to describe an energy and ecologically conscious approach to the design of the built environment.

Meanwhile, According to the British Columbia Float Home Standards, float home means a structure incorporating a floatation system, intended for use or being used or occupied for residential purposes, containing one dwelling unit only, not primarily intended for, or usable in navigation and does not include a watercraft designed or intended for navigation. Therefore floating architecture can be defined a building for living/working space on floatation system without navigation tool. Therefore sustainability of floating architecture can be interpreted as an energy and ecologically conscious approach to a building for living/working space on floatation system without navigation tool.

Sustainable Features from Sample Floating Architectures

Sustainable features of the sample floating architectures can be summarized as following (see Table 2);

– Recycled usage and relocatable: Four Seasons Hotel showed a good example of long term usage by the relocation of 3 areas. Floating building can be moved to different locations and used by different people for a long time.
– Renewable energy: Most floating building adopts various renewable energy systems such as the geothermal use of sea water, solar energy, and wind power. Renewable energy on water is easier to get than land because there are no obstacles.
– Self-supporting plant: Large floating buildings have a self-contained system in terms of electricity, water and sewage treatment because connecting and maintaining the service lines far from the land is not easy.
– Modular system: Some planned floating buildings suggest prefabricated module. Construction waste can be discharged to the minimum and the building might be very easy and economical to maintain.
– Others: New materials such as ETFE covering instead of glass and plastic composite material instead of steel & concrete, and open layout to adapt different functions over time are introduced

Sample Floating Architectures

Some illustrative cases of sustainable Floating Architecture are described below:

Floating Pavilion, Rotterdam, Netherlands, 2010

The Floating Pavilion (Figure 11) in Rotterdam has a complex consisting of three floating Half-spheres with diameters of 18.5, 20 and 24 meters respectively, and with total floor area 1,104 square meters. The pontoon is made of expanded polystyrene (EPS) combined with a grid of concrete beams.

 

 

Solar thermal collectors & absorption material on the roof and Phase Change Material (PCM) in wall liquefy/solidify when the auditorium warms up/cools down. The geodesic domes are covered with extremely lightweight ethylene tetrafluoroethylene (ETFE) foils. The foil-roof consists of three layers, filled with air under pressure for insulation. Air convection streams are created between windows on ground floor level and in the top of the roof. Wastewater is purified and reused for flushing toilets. Even the toilet water is purified and discharged into the surface water. The entire facility is designed to accommodate approximately 500 visitors. And the auditorium can be used for groups up to 150 people. Various conferences and social events can be available with its remarkable shape as a landmark.

IBA Dock, Germany, 2009

The IBA Dock (Figure 12) as the information and event center is constructed upon a floating pontoon. The building is being used for Urban and Architecture information center in Hamburg.

 

 

The IBA Dock has 3 storey’s and 1,640 square meter floor area. The building is situated on an approximately 43m long and 26m wide concrete pontoon, and the superstructures are made of steel in prefabricated modular construction. The building is setting new standards in the area of climate protection such as 25 cm thick insulated outer walls

The building is based on “zero balance concept”, which focuses on solar energy management and systems that provide buildings with sustainable heat and cooling all year round. 16 solar thermal collectors with about 34 square meters on the roof are positioned facing south. Together with solar energy, some more energy is drawn from the Elbe using a heat exchanger built into the base of the concrete pontoon. This provides both the heating and cooling requirements for the water and air conditioning of the building through ceiling fixtures. The heat pump, along with a ventilating machine that provides air exchange for the entire building, is powered by 103 square meter of south-facing solar photovoltaic(PV) modules located on the roof terrace and angled at 30 degrees. Because the electricity needed by the heat pump is covered by solar PV cells, no further cooling or heating energy is needed.

Autark Home, Netherlands, 2012

Autark Home (Figure 13) is a self-sufficient and passive floating home with European passive house certificate. The floating home has 2 storeys, 109.4 square meter floor area, outer wall with 55cm thick massive EPS, isolated windows and doors, triple glass and no cold bridges. There is an isolated water tank with a capacity of 4,000 liters and 6 solar thermal collector panels on the roof to keep the temperature of 70 to 80 degree for 4 to 5 days. River water is converted to gray water through a filter. And high-quality drinking water is purified through reverse osmosis in combination with the sand and UV filter. Before the wastewater returns to the river, the water is cleaned for 90% by a built-in filtration system. The incoming fresh air is heated or cooled by outgoing exhausted air through a heat recovery ventilation system.

The electricity is supplied by 24 solar PV modules. The electrical energy is stored in 24 batteries, supplying enough electricity for 4 days for a normal family. The system can deliver 5,300 kWh a year. On the display of the monitoring system in living room, solar production can be watched. In bad weather condition, a bio-diesel generator supplies the home with additional power.

Makoko Floating School, Nigeria, 2013

Makoko Floating School (Figure 14) is a prototype floating structure with an area of 220 square meters, built for the historic water community of Makoko, Lagos, Nigeria. As a pilot project, it has taken an innovative approach to address the social and physical needs of the community considering the impact of climate change and a rapidly urbanizing context. The overall composition of the design is a triangular A-Frame section, with the classrooms located on the second tier. They are partially enclosed with adjustable louvered slats. There is a playground below, and the roof has an additional open air classroom. It is designed to use solar PV modules, to adapt natural ventilation, to recycle organic waste and to collect rainwater for the toilet. Bamboo and wood from the local community are used as the main material as the structure, support and finishing for the completed school. The whole structure sits on a base of typical plastic barrels. The barrels at the periphery can be used to store excess rainwater from the catchment system.

Brockholes Visitor Centre, UK, 2012

A new nature reserve named Brockholes (Figure 15) was created from the abandoned remains of a quarry near Preston, UK. The 1,400 square metre floor area building sits on a 2,795 square meter concrete pontoon. The center comprised a cafe, conference center and education facilities as well as an exhibition space and retail shops. The highlight is the beautiful floating eco-village with decks for visitors to enjoy the peaceful surroundings. Brockholes sits on a buoyant concrete raft, held by four steel posts to stop it drifting across the lake. It can rise up to 3 metres, which would only be necessary for a catastrophe, but will regularly rise up and down by 40cm over a year because the site is prone to flooding with a one-in-100-year risk of up to 3 meters and has an annual water level variation of 40 cm. The architect designed high, steep-pitched roofs enclosing large volumes (good for air circulation and extraction), clad in oak shakes – rough tiles. Gutters are made of copper (long-life, recyclable). Grey water system and woodchip boilers add to the green scores. Ventilation is entirely natural. Insulation is a cheap but effective material made from recycled newspapers.

The facade is an environmental system, helped by external awnings which provide the best form of shading in summer. The low-level window seats mean that efficient natural ventilation and views out are not obstructed. In winter the internal space can receive maximum daylight and passive solar heating. The deck now sits above the water with a freeboard of only 150mm, giving the feeling of intense proximity to the lake.

Oregon Yacht Club, Portland, USA, 1910

Oregon Yacht Club (OYC, Figure 15) is a community with 38 floating homes on the Willamette River, Portland, Oregon. The close proximity of downtown with pastoral setting of OYC is regarded as one of the best floating-home villages in the area.

In OYC, there is a floating house with 2 storey’s and 212 square meters. That is ultra-low energy house and the entire structure is made of glued laminated wood sections for swirling and curved design. This kind of construction not only makes versatile forms but also greatly reduces the overall amount of material used, and so is very light and easy to produce. The window wall is only for taking in amazing river views and the glass allows the solar heat and light during the day while providing natural ventilation. With the materials prefabricated and transportation by boat, the home construction required minimal amounts of energy, and most importantly, did not disrupt the atmosphere of the floating home community. The house is integrating a beautiful, modern home into its surrounding environment.

In floating home community, residents enjoy the peaceful and comfortable atmosphere on the water within the natural setting. They believe the best view is seeing only the natural elements such as sky, mountain & trees, grain field, and water without any artificial features. Connection to nature is likely to generate positive states of well-being and health. The residents have great interesting in conserving the natural environment like wild birds and watershed vegetation, have to cooperate in managing the natural disaster like flooding and typhoon, have to cope with the fire and escape, and should negotiate the legal regulation with the city officers and get administrative/financial support from the City government. Solid social sustainability is essential and easy to be found in floating home community.

Very Large Floating Structures (VLFSs) and Very Large Floating Platforms (VLFPs)

Very large floating structures (VLFSs) or very large floating platforms (VLFPs) are man made islands, which may be constructed to create floating airports, bridges, breakwaters, piers and docks, storage facilities (for oil & natural gas), the wind and solar power plants, for military purposes, to create industrial space, emergency bases, entertainment facilities (such as casinos), recreation parks, mobile offshore structures and even for habitation. Currently, several different concepts have been proposed for building floating cities or huge living complexes. Some units have been constructed and are presently in operation. Floating structures offer several advantages over more permanent structures which might extend from the shore into open water.

VLFS differ from watercraft in that the usable area is the top surface instead of the internal (hold) areas. Thus a useful VLFS will cover a significant area. It can be constructed by joining the necessary number of floating units together. The design of the floating structure must comport with safety and strength requirements, operating conditions, etc. Steel, concrete (pre-stressed or reinforced hybrid) or steel-concrete composite materials may be used to build the floating structure. The motion of the floating structure due to wind or wave action must be substantially neutralized, to ensure the safety of people and facilities on a VLFS, and to allow useful activities. VLFS must be securely moored to the ocean bed.

Current Designs of VLFS

The semi-submersible-type VLFS has a raised platform above sea level using column tubes; it is more suitable for deployment in high seas with large waves. In the open sea, where the waves are relatively large, the semi-submersible VLFS minimizes the effects of waves while maintaining a constant buoyant force. Semi-submersible types are used for petroleum exploration in deep waters. They are fixed in place by column tubes, piles, or other bracing systems.

The pontoon-type VLFS platform rests on the water surface and is intended for deployment in calm waters such as a cove, a lagoon or a harbor. Its basic element is a simple box structure; it usually offers high stability, low manufacturing cost and easy maintenance and repair. The pontoon type is supported by its buoyancy on the sea surface. The pontoon type is flexible compared to other kinds of offshore structures, so that the elastic deformations are more important than their rigid body motions. Thus, the hydro-elastic analysis is uppermost in designing the pontoon-type VLFS. Together with the motion of the floating structure, the response of the structure to water waves and the impact on the entire fluid domain needs to be studied.

Floating Airport

As of 2002, the largest offshore structure built is the Mega-Float, a floating airport prototype that was constructed in Tokyo Bay from 1998 to 1999. It is one kilometer in length, and was primarily intended as a test vehicle, to research the loadings and responses of such installations. This project was substituted as a study project to provide more definite information about a proposed floating runway at Kansai International Airport, which was not built (an artificial island was instead constructed to support the runway).

Floating Landing Platforms

As of October 2014, Space Exploration Technologies (SpaceX) has contracted with a Louisiana shipyard to build a floating landing platform for reusable orbital launch vehicles. The initial platform has an approximately 90 by 50 meters (300 ft × 160 ft) landing pad surface and is capable of precision positioning with diesel-powered Azimuth thrusters so the platform can hold its position for launch vehicle landing. This platform was first deployed in January 2015 when SpaceX attempted a controlled descent flight test to land the first stage of Falcon 9 Flight 14 on a solid surface after it was used to loft a contracted payload toward Earth orbit. The platform utilizes GPS position information to navigate and hold its precise position. The rocket landing leg span is 18 m (60 ft) and must not only land within the 52 m (170 ft)-wide barge deck, but must also deal with ocean swells and GPS errors.

Offshore Floating Architecture

This section gives a brief overview of fixed and mobile offshore units, such as dredgers, pipe laying vessels, drilling vessels, oil production, storage and off-loading units and several types of support and transportation vessels.

Pipe Laying Vessels

One of the problems of laying pipes on the seabed lies in the limited capacity of the pipe to accept bending stresses. As a result, it is necessary to keep a pipe line under considerable axial tension during the laying operation otherwise the weight of the span of the pipe between the vessel and the point of contact of the pipe on the sea bed will cause the pipe to buckle and collapse. The tension in the pipeline is maintained using the anchor lines of the pipe laying vessel. The tension is transferred to the pipe by means of the pipe line tensioner located near the point where the pipe line leaves the vessel. The pipe tensioner is designed to grip the pipe without damaging the pipe coating (concrete) and ease the pipe aft while retaining pipe tension as the vessel is hauled forward by the anchor winches. Forward of the tensioner, additional sections of the pipeline are welded to the already existing part. Aft of the tensioner, part of the free span of the pipeline is supported by a so-called stinger.

Pipe laying vessels can consist of semi-submersibles or ship-shaped hulls. Semi-submersibles have the advantage of better motion characteristics in waves which are beneficial for the pipe laying operation. On the other hand, ship-shaped vessels have a higher variable load capacity and a much higher transit speed. Pipe laying vessels are usually moored by means of anchor systems which are continually being relocated as the laying operation progresses. A new development is a pipe laying vessels kept in position and deriving the pipeline tension by using a dynamic positioning (DP) system instead of anchor lines; for instance pipe laying vessel ’Solitaire’, operated since 1998 by Allseas Marine Contractors. Figure 16 shows a comparison of this vessel with the much smaller ’Lorelay’ of this company, operated since 1986. The considerable increase in size is obvious here.

With respect to the combined effect of vessel and pipe motions and the dynamic positioning performance, analyses have to be carried out to end the sea state that can be regarded as the maximum operational condition.

Drilling Vessels

When geological predictions based on seismic surveys have been established that a particular offshore area offers promising prospects for finding oil, a well is drilled to examine these predictions. These drilling operations are carried out from barges, ships, semi-submersibles or jack-up rigs (Figure 17).

For floating drilling units it is important that they can work in high sea conditions. Generally, semi-submersibles will have the least vertical motions and hence the highest workability. In order to enhance further the workability of drilling vessels, the vertical motions of the vessel at the location of the drill string are compensated for by a so-called heave compensator. This device is essentially a soft spring by means of which the drill string is suspended from the drilling tower on the vessel. In this way, the drill string can be maintained under the required average tension, while the vertical motions of the vessel – and hence of the suspension point of the drill string in the drilling tower – do not result in unduly high drill string tension variations or vertical movement of the drill bit. Also, the marine riser is kept under constant tension by means of a riser tensioning system. Horizontal motions are another factor of importance for drilling vessels. As a rule of thumb, the upper end of the drill string may not move more to one side of the center of the drill than approximately 5 % of the water depth. This places considerable demands on the mooring system of the vessels. Semi-submersible drilling vessels are generally moored by means of 8 to 12 catenary anchor legs. Drill ships can be moored by means of a spread mooring system which allows a limited

Floating Production Units

Floating Production Units (FPUs) are used for oil production at smaller fields. In very deep water they are also economically attractive for large oil fields. The production equipment and accommodation is placed on a floating structure, permanently moored to the seabed. They have no storage capacity. The oil is offloaded to a Floating Storage and off–loading unit (FSO). Figure 18 shows an overview of this.

Two types of floating production platforms without storage capacity can be distinguished: the semi-submersible and the tension leg platform (TLP). Production on a TLP in remote areas – so that a pipeline is uneconomical – requires external storage capacity, for instance by using a storage tanker moored nearby. A Semi-Submersible Platform consists of a rectangular deck structure supported by 4 to 8 surface-piercing vertical columns standing on submerged horizontal ‡oaters. These vessels have good motion characteristics and do not require the heading changed as the predominant direction of the weather changes. The vessels are moored by means of 8 to 12 catenary mooring lines consisting of chains or combinations of chain and wire. Parts of the pipe lines transporting the oil to the ‡oater have to be flexible to allow for the wave-induced motions of the floater. These flexible pipelines have to be succinctly strong and resilient to withstand high pressures and temperatures of the crude oil as well as the continual flexing due to the floater motions (Figure 19).

The aspects of importance or interest are generally the same as those for drilling semis. However, the production semi-submersible will be permanently moored which means that – consequently – more stringent demands are placed on the design.

Floating Production, Storage and Off–loading Vessel

A Floating Production, Storage and Off-loading vessel (FPSO) is generally based on the use of a tanker hull, which has been converted for the purpose. Such vessels have a large storage capacity and deck area to accommodate the production equipment and accommodation (Figure 20). When converting old tankers for this purpose, special attention has to be paid to the fatigue life of the vessel. Motion characteristics of such vessels are acceptable as long as the vessel can ’weathervane’ with the predominant direction of the wind and the waves. This requires that a single point mooring system be used by means of which the vessel is effectively held at the bow or stern by the mooring system and allowed to rotate freely around that point. A complicating factor of the SPM system is the need to include fluid swivel systems in the oil transport system to and from the vessel. In some sheltered locations it is not necessary to apply an SPM type mooring system. In such cases, a spread mooring system which holds the vessel in a fixed mean heading direction is the preferred solution since no swivels are required in the oil transport lines to and from the vessel. Due to the wave-induced motions of the FPSO, the oil transportation lines to the vessel have to be flexible.

Flood Proof Architecture

Concepts and constructive solutions to adapt to rising water levels Johan van der Pol (Dura Vermeer, the Netherlands) Introduction Soil compaction and subsidence, urbanization and climate change increase the vulnerability of (urban) areas to floods. The government is going to invest heavily in the necessary knowledge development, to be able to face climate change. For this task, the building trade can and should make a crucial contribution with new concepts of ‘’building with water’. Especially in highly populated areas, living with water may be a sustainable adaptive solution for future challenges. More and more Dutch designers are getting into ‘flood proof’ architecture. This has already led to a whole range of concepts and constructive and non-constructive solutions. Noticeable examples of building methods are: floating construction, amphibious construction, construction on piles, elevated construction, dry- and wet proof construction. Practical examples are floating- and amphibious houses, platform houses, artificial islands or reefs, floating offices and floating greenhouses. These items are the specialism of Dura Vermeer, a construction and development company in the building industry. This article illustrates some of their concepts.

Floating Greenhouses

Floating greenhouses offer the opportunity to combine two functions on the same square metre: greenhouse horticulture and water storage. There is an increasing demand for this multiple uses of space, because space in The Netherlands is restricted, while the demand for living-, working- and recreational locations is increasing. In the years to come, many tens of thousands of hectares will be used for water storage, taking up valuable space. Creating space for water storage is not simple in a densely populated country as the Netherlands. Combining water storage with an economic function may more easily create the necessary space. The concept of floating greenhouses has been developed from the idea that it contributes to the solution of spatial limitations that arise from the redevelopment of greenhouses and will create space/ room for water storage. A pilot project for a floating greenhouse is to be realised in the province of South-Holland. The lowest point of The Netherlands is situated in this area: 6, 76 metre below NAP (NAP = about average sea level). The idea is to plan an area where a pilot project floating greenhouse can be realised on a commercial basis. The pilot will be an example of a sustainable development of glasshouses combined with water storage. Apart from the development of a floating greenhouse, the business case also comprises a research programme covering the environmental effects.

A public-private partnership has been working on the business case for two greenhouse growers since 2005. In 2012 we hope to finally celebrate the opening of the five hectares floating Greenhouse: the Floating Roses. III-3-3-3 First – built floating greenhouse in the world – Demonstration version, municipality of Westland (photos: Dura Vermeer). 168 Climate of Coastal Cooperation Amphibious and floating homes Unlike the houseboats that line many Dutch canals or the floating villages of Asia, these amphibious homes are being built on solid ground — but they also are designed to float on flood water. They look much like regular houses; the only difference is that when the water rises, they rise. Each house is made of lightweight wood, and the concrete base is hollow, giving it ship-like buoyancy. With no foundations anchored in the earth, the structure rests on the ground and is fastened to 15-foot-long mooring posts with sliding rings, allowing it to float upwards in times of flood. All the electrical cables, water and sewage flow through flexible pipes inside the mooring piles. Realisation in Maasbommel The desire to integrate water management issues in the Netherlands in sustainable spatial planning, has led Dura Vermeer to translate this aim into the development and realisation of 32 amphibious and 14 floating houses in Maasbommel in the Province of Gelderland. The houses are the solution to the demands for living-, working and recreational space and the need for sound and sustainable water storage. The location in Maasbommel is just outside the dyke ring in a water recreational area, connected with the river Maas.

Recent flood events and the subsequent strengthening of the dykes in the river basin have led to the development of houses by an entirely new concept: houses that will float at high water. In order to enable the houses to move with the fluctuating water level, the houses are fixed on concrete floating platforms with a suspension mechanism.

In recent years, the knowledge and experience in the field of flood proof construction has increased strongly. It is an issue, which is not only relevant to the Netherlands, but has also been taken up by other countries. Some remarkable examples of practical applications have been realised, from which learning points are being shared. These experiences are subsequently used in developing the expertise and concepts further and its translation into daily construction practice. This means that expertise is now available for modelling damage because of flooding, construction concepts have also been elaborated, which is based on a sound financial footing, situation-specific and solutions offered and cost-benefit analyses made. The concepts of flood proof architecture can be an efficient method for adapting to the potential impacts of climate change.

Amphibious and Floating Flood- Resistant Homes

Unlike the houseboats that line many Dutch canals or the floating villages of Asia, these amphibious homes are being built on solid ground — but they also are designed to float on floodwater. They look much like regular houses; the only difference is that when the water rises, they rise. Each house is made of lightweight wood, and the concrete base is hollow, giving it ship-like buoyancy. With no foundations anchored in the earth, the structure rests on the ground and is fastened to 15-foot-long mooring posts with sliding rings, allowing it to float upwards in times of flood. All the electrical cables, water and sewage flow through flexible pipes inside the mooring piles.

The desire to integrate water management issues in the Netherlands in sustainable spatial planning, has led Dura Vermeer to translate this aim into the development and realisation of 32 amphibious and 14 floating houses in Maasbommel in the Province of Gelderland. The houses are the solution to the demands for living-, working and recreational space and the need for a sound and sustainable water storage. The location in Maasbommel is just outside the dyke ring in a water recreational area, connected with the river Maas. Recent flood events and the subsequent strengthening of the dykes in the river basin have led to the development of houses by an entirely new concept: houses that will float at high water. In order to enable the houses to move with the fluctuating water level, the houses are fixed on concrete floating platforms with a suspension mechanism. At a low water level, the houses rest upon a foundation of concrete. To keep the houses as light as possible the framework consists of timber. To prevent the houses from floating away at high water they are fixed to flexible moorings, with which tugs can be absorbed. It is expected that once every five years the water level will rise so much (over 70 centimetres) that the houses will indeed float. The houses can cope with a water level difference of up to 5, 5 metres. That is above the height of the top of the levee.

In recent years, the knowledge and experience in the field of flood proof construction have increased strongly. It is an issue, which is not only relevant to the Netherlands, but has also been taken up by other countries. Some remarkable examples of practical applications have been realised, from which learning points are being shared. These experiences are subsequently used in developing the expertise and concepts further and its translation into daily construction practice. This means that expertise is now available for modelling damage because of flooding, construction concepts have also been elaborated, which is based on a sound financial footing, situation-specific and solutions offered and cost-benefit analyses made. The concepts of flood proof architecture can be an efficient method for adapting to the potential impacts of climate change.

 

Dr. A.N. Sarkar
Ex-Senior Professor (International Business) & Dean (Research), Asia-Pacific Institute of
Management, New Delhi

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