No Tech Magazine

Carrier Pigeons in Syria

2012-02-16T12:04:00+01:00

Cut off by a relentless barrage of government shelling, activists in the besieged Syrian city of Homs have reverted to the age-old practice of using carrier pigeons to communicate with each other. More.

Chinese Wheelbarrow Lives on in Angola, Africa

2012-02-16T12:02:00+01:00

The ingenious Chinese wheelbarrow lives on in Angola, Africa. The contemporary design is similar to the Ancient Chinese vehicle, except it uses straight boards and a car tyre.

The machine and the men pushing it are both called "roboteiros".

Picture credit.

More pictures: 1 / 2 / 3 / 4 / 5 / 6 / 7 / 8 / 9 / 10 / 11 / 12.

Thanks to Marco Cecilio.

Mumbai Rickshaws

2012-02-09T16:11:15+01:00

"Recognizing the role that auto-rickshaws play in sustainable urban transport and meeting daily commute needs in Mumbai will go a long way in improving conditions for drivers, as well as passengers, and will result in social and environmental benefits for Indian cities, as a whole."

And why not in the rest of the world? Mumbai Rickshaws. Via Emile Hooge. More low-tech cars.

Pedal Powered Wool Carding Machine

2012-02-09T15:41:22+01:00

The Cyclocarder by Fibershed-contributor Katharina Jolda is a wonderful update to the article on pedal powered machines. The Cyclocarder can turn your backyard, community center, or farm into a human powered wool processing station.

California Coolers

2012-02-05T23:34:28+01:00

"Coastal Northern California is blessed with a very moderate climate, generally on the cool side, especially at night. Before the refrigerator became common in households, denizens of this region took advantage of the cool weather by storing perishable foods in a special kitchen cabinet that brought in air from the outside - the California Cooler.

The cooler cabinets were designed to hold fruits, vegetables, and other staples that needed to be kept cool but didn’t need to take up critical space in the era’s tiny ice boxes. The coolers were open to the basement to draw in cool air, which then wafted up and out a chimney or a wall vent.

When the refrigerator came along, it seems that, over time, the vents were boarded up and the California Cooler was all but forgotten. Today, if you walk the streets of my hometown, Berkeley, where most of the houses were built in the 1920's, you will see many homes, and even apartment buildings, with the exterior vestiges of these vents."

Read more: Resurrecting the California Cooler. Thank you, Adriana. Previously: Saving food from the fridge.

Energy Cannibalism

2012-01-31T15:22:18+01:00

Energy cannibalism refers to an effect where rapid growth of an entire energy producing (or conserving) technology industry creates a need for energy that uses (or cannibalizes) the energy of existing power plants or devices. For the deployment of renewable energy and energy efficiency technologies to grow while remaining net greenhouse gas emission mitigators, they must grow at a rate slower than the inverse of their energy payback time.

"Optimizing greenhouse gas mitigation strategies to suppress energy cannibalism", J.M. Pearce, 2nd Climate Change Technology Conference, Hamilton, Ontario, Canada, May 12-15, 2009. (PDF).
"Energy payback for energy systems ensembles during growth", Timothy Gutowski, International Symposium on Sustainable Systems and Technologies, Washington D.C., May 16-19, 2010. (PDF)
"Toward real energy economics: energy policy driven by life-cycle carbon emission", R. Kenny, C. Law, J.M. Pearce, Energy Policy 38, pp. 1969-1978, 2010. (PDF)
"Thermodynamic limitations to nuclear energy deployment as a greenhouse gas mitigation technology", Joshua M. Pearce, Int. J. Nuclear Governance, Economy and Ecology, Vol. 2, No. 1., pp.113-130, 2008. (PDF)

Previously: Can renewables power consumer societies? The negative case.

Where Are The Adults?

2012-01-29T13:09:20+01:00

"Science has enjoyed broad public support as a foundation for technology. But as science increasingly tells us what we can’t expect to do in a world of diminished resources and compromised environment—rather than only opening up new possibilities—we’ll see how popular science remains." Read more: The future needs an attitude adjustment.

Locally Farmed Clothing: The Fibershed Project

2012-01-27T02:21:59+01:00

"In 1965, 95% of the clothing in a typical American’s closet was made in America. Today less than 5% of our clothes are made here. Unfortunately, this huge movement of the industry was not prompted by a desire for higher standards of production, economic equity for laborers, or tight environmental regulation. It was done to circumvent the policies, unions, and costs associated with doing business on shore. We have off-shored the effects of our consumption, which has led to a great disconnect of the actual environmental and social costs of our clothing."

"A bioregional supply chain known as a Fibershed aims to bring a thriving local alternative to conventional textile manufacturing systems and to support communities in reviving, sustaining, and networking their raw material base with skilled design and artisanal textile talent."

"The Fibershed project began in 2010 with a one-year challenge to create an experimental wardrobe from fibers, dye plants, and local labor all sourced from within 150 miles of the project headquarters. As the wardrobe was constructed over the one-year period, so, too, was the network of artisans and farmers responsible for its creation."

"The garments were primarily hand-constructed. The rural region proved to be rich in raw materials: word-class alpaca, the finest merino wools, color-grown cottons, and the softest angora. The design talent from the urban sector was abundant in skills, experience, and passion. Many of the essential elements necessary to engage a bioregional supply were in place: the animals, plants and people. However, the necessary machinery to produce conventional clothing was nowhere to be found. The group relied on time-honored skills that artisans throughout time have relied upon to make cloth: spinning wheels, knitting needles, and floor looms."

"We at Fibershed hope our model can serve as a guide for other communities interested in increasing their resiliency and self-sufficiency. We also hope it offers inspiration that sustainable, local solutions for almost any product or service can be successfully developed by those willing to dream big and put in the sweat work to make it a reality."

The Greenest Building Is The One Already Standing

2012-01-25T16:12:30+01:00

"Until now, little has been known about the climate change reductions that might be offered by reusing and retrofitting existing buildings rather than demolishing and replacing them with new construction. This groundbreaking study concludes that building reuse almost always offers environmental savings over demolition and new construction. Moreover, it can take between 10 and 80 years for a new, energy-efficient building to overcome, through more efficient operations, the negative climate change impacts that were created during the construction process." Read more.

Saving Food From The Fridge

2012-01-16T18:33:00+01:00

Korean artist Jihyun Ryou, a graduate of the Dutch Design Academy Eindhoven, translates traditional knowledge on food storage into contemporary design. She found the inspiration for her wall-mounted storage units while listening to the advice of her grandmother, a former apple grower, and other elderly. Her mission: storing food outside the refrigerator.

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On her blog, "Shaping traditional oral knowledge", Jihyun Ryou explains the motivations underlying her work, which actually go beyond food storage:

"This project is about traditional oral knowledge which has been accumulated from experience and transmitted by mouth to mouth. Particularly focusing on the food preservation, it looks at a feasible way of bringing that knowledge into everyday life. Through the research into the current situation of food preservation, I’ve learned that we hand over the responsibility of taking care of food to the technology, the refrigerator. We don’t observe the food any more and we don’t understand how to treat it. Therefore my design looks at re-introducing and re-evaluating traditional oral knowledge of food, which is closer to nature. Furthermore, it aims to bring back the connection between different levels of living beings, we as human beings and food ingredients as other living beings. Through the objects of everyday life, design can introduce traditional oral knowledge into people’s lives through their experience of using it. Objects make invisible knowledge evident."

Talking about fruits and vegetables as living beings sounds rather woolly, but it is actually true. Vegetables and fruits continue to live even after they are picked. They keep breathing, taking oxygen from the air and giving off carbon dioxide, water vapour and heat. By regulating temperature and humidity, it is possible to slow down this respiration, resulting in a longer storage time.

Storing food outside the refrigerator

While many fruits and vegetables benefit from the low storage temperature in a refrigerator (around 40 degrees F or 4.5 degrees C), this is not true for all of them. So-called fruit vegetables such as peppers, courgettes, aubergines and tomatoes require higher temperatures and decay more rapidly in the refrigerator. They need high relative humidity, though. The shelf pictured above gives these vegetables a suitable space. Through the ritual of watering them everyday, they will stay fresh. The water not only raises humidity but also cools the produce, assuring a temperature that is higher than that in the refrigerator but lower than that in the room.

The same principle is applied to the fruit bowl shown above, in which a perforated dish sits over a bowl of water. The concept is inspired by the old farmer's wisdom to preserve fruits fresh before selling.

Damp sand

Keeping vegetables in slightly damp sand has been a storage method for many centuries. While low temperatures are favourable for vegetables like carrots, high humidity is equally important. Keeping them in wet sand can be a good compromise. In the design above, this concept is improved by burying the vegetables upright, mimicking their growth conditions - and making them last longer, says Jihyun Ryou. Just don't forget to water them from time to time.

Rice absorbs humidity

Other foods, like spices, garlic, onions and sweet potatoes, require low humidity but higher temperatures, which also makes them unstuibale for storage in a refrigerator. Because it absorbs moisture easily, rice can be of great help here. In the design above, the cork lid of each spice container contains a small space holding rice, which helps to keep the spices dry without forming into lumps.

Ethylene gas

Some fruits and vegetables (notably apples but also tomatoes, avocados, bananas, muskmelons, pears, plums, and peaches) emit ethylene gas. This has the effect of speeding up the ripening process of fruits and vegetables kept together with them, which is why it is wise to store ethylene producing fruits and vegetables separately. However, when combined with potatoes, Jihyun Ryou says, they have a positive effect, because the ethylene gas prevents the potatoes from sprouting. The design pictured above consists of a wooden box that keeps potatoes in the dark (a more common way to keep them from sprouting), while the holes on top allow them to benefit from the ethylene gas emitted by the apples.

The same design could also be used to accelerate the ripening of tomatoes, a process that is used - on a much larger scale - by food distributors.

Does it work?

The more food you can keep out of the fridge, the smaller it needs to be and the less energy it will consume. The designs described above show a refreshing way to do that, although it should be remembered that these are artworks, not consumer products. Using similar methods when storing food in a basement or a specially designed root cellar - the traditional way - will give better results (more on that in a forthcoming article). Furthermore, some of the storage strategies followed by Ryou are not generally accepted. Most of the sources that I have consulted (books, not grandmothers) say that ethylene gas will promote the sprouting of potatoes, not prevent it.

Anyway, her work will certainly encourage others to search for alternative storage solutions based on traditional knowledge - and that's what it is all about. Experience and experimentation will tell what works and what not.

More at Jihyun Ryou's blog: "Shaping traditional oral knowledge" and in this video. She also offers a beautiful booklet. An overview of temperature and humidity requirements for most vegetables and fruits can be found here (.pdf).

We will publish more on low-tech food storage soon. Stay informed via email, feed, twitter or facebook.

Thanks for the tip, mom!

People Are Knowledge: The Oral Citations Project

2012-01-16T18:31:34+01:00

"The Oral Citations Project is a strategic research project funded by a Wikimedia Foundation grant to help overcome a lack of published material in emerging languages on Wikipedia. The idea behind the project is a simple one. Wikipedia privileges printed knowledge (books, journals, magazines, newspapers and more) as authentic sources of citable material. This is understandably so, for a lot of time and care goes into producing this kind of printed material, and restricting citation sources makes the enterprise workable. But books - and printed words generally - are closely correlated to rich economies: Europe, North America, and a small section of Asia."

"In India and South Africa, for instance, (to take just two countries in the rest of the world), the number of books produced per year is nowhere close to, say, the number of books produced in the UK. What this means for indigenous language Wikipedias from India and South Africa is that there is very little citable, printed material to rely on in those languages; in turn, it means that it is very difficult for any of those languages to grow on Wikipedia. (There is a related problem: writing this local knowledge on English Wikipedia is a task similarly hampered by a lack of good printed sources)."

"As a result of this disparity, everyday, common knowledge - things that are known, observed and performed by millions of people - cannot enter Wikipedia as units of fact because they haven't been written down in a reliably published source.This means that not only do small-language Wikipedias in countries like India and South Africa lose out on opportunities for growth, so also does the Wikimedia movement as a whole lose out on the potential expansion of scope in every language."

Description of the project, audio files, movie and links to news articles can all be found on this page. Via Appropedia.

The Wooden Work Boats of Indochina

2012-01-14T19:40:04+01:00

"The wooden work boats of Vietnam, Cambodia and Laos (French Indochina) have a long and fascinating history of sail and trade in South East Asia and beyond. Today, the sails are nearly all gone but the boats and their builders survived by adapting the traditional sailboat hulls for motoring. Our goal is to document the building, design and uses of as many traditional and unique wooden work boats of Southeast Asia as possible before the master craftsmen who build them are gone."

Great pictures at Boats and Rice. Via Duckworks Magazine. Previously: The Junk Blue Book. More boats.

Micro Heaters

2012-01-06T13:21:03+01:00

"In June of 2010 I moved to a place in Montana with only electric heat. By myself. In the past few winters I had conducted experiments in cutting the amount of energy I needed to stay warm, with a focus on heating myself instead of heating the whole house."

"I had a lot of motivators here, but the primary motivator was the greenwashing being done around fluorescent light bulbs. My power company sent me literature telling me that I should replace all of my incandescent light bulbs with fluorescent light bulbs to save energy and money. Based on my lighting usage, the most I could possibly save is $5 per year. Yet, with changing my heating habits, I think I have proven that I can save $500 per year."

Parabolic Basket and Tin Can Solar Cooker

2012-01-04T16:53:08+01:00

"The objective of this project is to create a solar cooker out of local invasive species and waste materials. We want to create a device that can pasteurize water and be an alternative to the use of fossil fuels for cooking food."

"The structure of the parabolic solar cooker will be made from the canes, or stems, of the locally invasive Himalaya blackberry. Canes will be harvested and dethorned so they can be woven into a parabolic basket shape. The Himalaya blackberry canes form parabolic curves, so when they dry and stiffen they will maintain the sturdy parabolic shape of the basket."

"To give the parabolic cooker its necessary reflective surface, we gathered around 300 tin can lids to line the inside of the basket. We punched holes in the can lids so we could string them together in lines of 8-10 lids each. Then we tied these lengths of can lids to the basket using either hemp twine or twist ties. Since there were still many spaces on the basket uncovered by can lids, we gathered a bunch of large can lids and attached those individually to the basket."

The Best Invention Since The Wheel

2012-01-04T16:50:25+01:00

"Between the third and seventh centuries AD, the civilizations of the Near East and North Africa gave up wheeled vehicular transportation and adopted a more efficient and speedier way of moving goods and people: They replaced the wagon and cart with the camel. This deliberate rejection of the wheel in the very region of its invention lasted for more than one thousand years. It came to an end only when major European powers, advancing their imperialistic schemes for the Near East, reintroduced the wheel."

"The camel as a pack animal was favored over wheeled transportation for reasons that become obvious when the camel is compared with the typical ox-drawn vehicle. The camel can carry more, move faster, and travel farther, on less food and water, than an ox. Pack animals need neither roads nor bridges, they can traverse rough ground and ford rivers and streams, and their full strength is devoted to carrying a load and not wasted on dragging a wagon's deadweight. Once the camel and ox are compared, one wonders why the wheel was ever adopted in that region in the first place."

"A large share of the burden of goods in the Near East was always carried by pack animals. A bias for the wheel led Western scholars to underrate the utility of pack animals and overemphasize the contribution made by wheeled vehicles in the years before the camel replaced the wheel. The more we learn about the wheel, the clearer it becomes that its history and influence have been distorted by the extraordinary attention paid to it in Europe and the United States. The Western judgment that the wheel is a universal need (as crucial to life as fire) is of recent origin."

Quoted from: "The Evolution of Technology", George Basalla, 1988. See also: "The Camel and the Wheel", Richard W. Bulliet, 1990 (summary). Previously: Camel trains in Asia, Russia and Australia.

Solar Powered Garden Helper Machine

2012-01-04T15:50:18+01:00

"I really love gardening but I have a bad back and when it comes to staying bent over in the garden it gets rough. So I built this Helper Machine. I call it My P-Machine. Planting/Picking/Pulling weeds/Putting around the garden machine."

More.

Hat tip to Rob De Schutter.

The Sustainable Urban Dwelling Unit (SUDU)

2011-12-27T15:10:08+01:00

The 'Sustainable Urban Dwelling Unit' (SUDU) in Ethiopia demonstrates that it is possible to construct multi-story buildings using only soil and stone. By combining timbrel vaults and compressed earth blocks, there is no need for steel, reinforced concrete or even wood to support floors, ceilings and roofs. The SUDU could be a game-changer for African cities, where population grows fast and building materials are scarce.

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In "Tiles as a substitute for steel", we highlighted the medieval art of the medieval timbrel vault, which allowed for structures that today no architect would dare to build without steel reinforcements. The technique is cheap, fast, ecological and durable. Shortly after the article was published in 2008, the timbrel vault made a comeback with two rather spectacular buildings: Richard Hawkes' Crossway Passive House in England, and Peter Rich's Mapungubwe Interpretation Centre in South Africa.

The cardboard formwork technique described last week promises to bring even more dramatic architecture, but at least as interesting is the news that the catalan vault is now also applied to a much more modest form of housing: the Sustainable Urban Dwelling Unit (SUDU), a low-cost family dwelling built in Ethiopia.

The Sustainable Urban Dwelling Unit (SUDU).

Though less spectacular at first sight, it could form the proof that even megacities can be constructed without the use of steel, concrete or wood. The double-story building, which was completed in last summer, is entirely made from soil and presents an economical and ecological solution to many of Africa's most urgent problems. The SUDU stands in Addis Ababa, Ethiopia, a country with a population of more than 80 million (growing at an average 7 percent per year). The building is a joint project of the Swiss Federal Institute of Technology (ETH Zurich) and the Ethiopian Institute of Architecture, Building Construction and City Development (EiABC).

The SUDU combines past technologies from different continents, resulting in a new approach to low-tech construction adapted to specific local conditions. In the Mediterranean region, where the timbrel vault originated, the tiles have traditionally been made from fired clay. In the SUDU, the construction technique is united with the African tradition of cement-stabilized, soil-pressed bricks, which use locally available soil. This technique is called compressed earth block (CEB) construction. The SUDU has been built largely following the same techniques used for the Mapungubwe Centre in South Africa.

Urban housing

The SUDU was designed to achieve both environmental and economic sustainability. Because Ethiopia has few material and financial resources, the design is aimed at eliminating the reliance on imported, expensive and energy-intensive building materials such as steel and concrete. More unusual is that the building also excludes the use of wood, for the simple reason that wood is equally scarce in the country. The entire structure is made from locally available construction materials - and in the case of Ethiopia, these are very few: soil and stone.

The Sustainable Urban Dwelling Unit (SUDU).

One of the most challenging present problems for Africa (and throughout the developing world) is the tremendous deficit in housing for the urban poor. In Ethiopia, this is reflected in the ubiquitous informal housing, comprising perhaps 80% of the built environment of its capital, Addis Ababa. The most common vernacular construction method – construction with Eucalyptus wood and mud – is an economically and environmentally sustainable method of construction, but the problem of such constructions is that they are limited to one story - putting a huge strain on available land.

Thus, this vernacular technology has been more recently replaced by large urban housing projects of reinforced concrete, heavily subsidized by the government. These massive edifices of concrete and steel neither offer a model for frugal, environmentally or economically sustainable construction, nor do they offer a low-cost alternative to housing because they are too expensive to construct. The result is that more and more people are forced to be living on the streets. Whether it is the United States or Ethiopia, governments seem to prefer homeless people over shanty-towns.

The Sustainable Urban Dwelling Unit (SUDU).

In poorer areas of Addis Ababa, dwellings are often constructed from corrugated metal. These dwellings cannot be expanded upon for multi-story construction, yet sprawl outward, consuming limited resources including wood, expensive imported materials, and land.

Urban density

The SUDU is an exploration of a "medium ground" between single story informal dwelling and massive scale urban density, as studies have shown that even two-story buildings dramatically impact urban density. As the example of Tokyo shows, a megacity can be largely based on double-story buildings. Because the other aim is to build using only locally available materials, and wood reserves are scarce, the goals of SUDU were to build two stories in soil - a significant challenge without the aid of steel, concrete or milled lumber. Multiple-story soil architecture has a long tradition in Africa, though none of it has been constructed without wooden beams.

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Building multiple stories in soil is a significant challenge without the aid of steel, concrete or lumber

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As soil and stone have limited tensile capacity, building with these materials demands compression-only structural solutions. For walls carrying dominantly vertical loads, this criterium is easily satisfied. However, once a space must be spanned, beam elements - which work in bending - are typically required. A beam, as a structural system, demands that its section can accomodate tension and compression forces, which is not possible when building in stone or soil only.

The Sustainable Urban Dwelling Unit (SUDU) under construction.

By adapting local soil knowledge to the production of soil stablized tiles, however, it is possible to introduce the technology of timbrel vaulting to allow floor and roof systems of pure compression in multiple story buildings. Ethiopia has a rich soil, which contains high levels of clay particles. Almost all excavated material in the city of Addis Ababa is a possible source for the material needed to build new structures. The SUDU uses rammed earth techniques to construct the first level of the building, with a 60 cm wide wall structure. The ceilings and floors and the building are done using a tiled vauling technique using sun-dried tiles (first floor) and loam (for the roof) made from the very same soil.

Contrary to most other vaulting techniques, the catalan vault does require little to no formwork, again bypassing the need for wood.

Model for low-cost housing

Apart from the ecological and financial benefits, the construction technique used in the SUDU offers additional advantages. By drawing upon traditional methods, it engenders pride and social cohesion within the local community. And by using only locally available materials, it provides local jobs, introduces new skills and stimulates self-sufficiency. Through the economic benefits, the SUDU may become a model low-cost housing unit for the urban poor in Africa. It is meant to be a showcase to convince decision makers, economists, urban planners and architects to rethink traditional building methods and find new ways to build a town or even a city.

The construction of the SUDU was led by Lara Davis, who published a blog where the building process is documented from A to Z. There is also a movie. The BLOCK Research Group of the Swiss Federal Institute of Technology (ETH Zurich) has a webpage that links to all the research papers on the construction method. A book was presented November 25. Also of interest is a special architectural 2010 issue of the ADTF Journal published by the African Technology Development Forum. Several articles deal specifically with timbrel vaulting building methods, and outline some of the remaining challenges:

Previously:

Timbrel Vaulting Using Cardboard Formwork

2011-12-22T16:54:35+01:00

Lara Davis, Matthias Rippman and Philippe Block from the Swiss BLOCK Research Group at the ETH Zurich University have taken the centuries old timbrel vaulting technique one step further by incorporating high-tech design tools (software and CNC fabrication) and low-tech materials (cardboard boxes and wooden palettes).

Find pictures and the research paper here or see the summary below.

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Timbrel vaulting (also known as 'Catalan vaulting' or 'thin-tile vaulting') offers a sustainable roof and floor construction method because it uses fewer building materials than conventional techniques. Timbrel vaulting employs the use of good structural form to achieve a minimal shell thickness and requires no formwork. The new tools designed by the Swiss researchers aim to combine these advantages with a whole new range of complex shapes, which they call 'freeform shells':

"This research project presents important advances in timbrel vaulting, made possible through innovation in form finding, guidework systems and construction methods. A full-scale prototype has been realized with the application of new research in the following areas: newly developed structural design tools based upon the Thrust Network Approach (TNA), which allow one to generate novel shapes for funicular (i.e. compression-only) structures; an efficient cardboard box guidework system, which allows for a vaulted surface to be described in an accurate manner in space for the mason; and adaptations upon traditional timbrel vaulting techniques, which have introduced strategies for continuous tiling patterns, shell thickening, and sequencing for structural stability during construction."

Matthias Rippmann designed both the prototype and the software tool, which is free to download:

"RhinoVAULT is software that allows for the intuitive design of compression-only shapes, offering a maximum control of the geometry. This software is written particularly for shaping unreinforced masonry vaults, but can also be used for designing efficient freeform shells. Based on the Thrust Network Approach (TNA), which uses a force network as discretization of the shape, it is possible to internally redistribute forces within the network using force diagrams. This enables the user to generate exciting forms far beyond typical 'hanging-net' morphologies."

Contrary to the traditional timbrel vaulting techniques, these new forms require a continuous formwork system. While this approach seems to negate the inherent material and labour efficiency of thin-tile vaulting, the researchers introduce a formwork system using cardboard that still possesses the material economy of the traditional Catalan shell:

"The cardboard formwork implemented in this project is fabricated with 2-D CAD-CAM cutting and gluing processes and is assembled on site. The system's rapid fabrication, lightweight transportation, and speed of erection and de-centering dramatically reduce the material and labour-based costs of construction. An inexpensive and potentially reusable/recyclable material, this lightweight cardboard formwork extends the viability of thin-tile vaulting to freeform construction."

The formwork system is expandable, essentially composed of simple boxes supported by stacked shipping palettes. Using palettes for the first rough approximation of the final vault shape offers several advantages: it reduces the volume of cardboard to be used, it facilitates easy access during construction as the palettes can be arranged in step-like configuration, and it decreases the size of the boxes, ensuring that the unrolled cutting pattern of boxes fit to the limited machine-size of the CNC cutting machine.

A particular challenge is de-centering, which is the process of removing the formwork from the surface of the shell. This is a sensitive process, because the entire formwork should be removed equally and simultaneously to avoid dangerous asymmetric loading cases from below. Such asymmetric loading would induce bending in a compression-only structure and potentially cause cracking and failure. To prevent this, the researchers developped a special mechanism:

"The entire formwork sits on top of a series of sealed plastic tubes containing cardboard spacers. Each spacer, which consists of a folded stack of cardboard sheets, taped together, supports the corners of typically four palettes. After the vault is completed, the tubes are filled with water, saturating the cardboard, causing it to compress under the load of the palettes and effectively to lower the formwork."

The construction (and eventual destruction) of the prototype, built by Lara Davis, is documented in a time-lapse video.

Davis L., Rippmann M., Pawlofsky T. and Block P. Efficient and Expressive Thin-tile Vaulting using Cardboard Formwork, Proceedings of the IABSE-IASS Symposium 2011, London, UK. (PDF).

Picture below: testing the strength of the structure.

Previously: