Professur Nachhaltiges Bauen / Sustainable Construction

Zuerich/Addis Ababa/Singapore March 2012

The Arthur Waser Foundation, based in Lucerene Switzerland, recently agreed to sponsor a continuous research project called SRDU (Sustainable Rural Dwelling Unit) in Ethiopia to the tune of 460,000 Swiss Francs over the next three years. The project builds on an academic research cooperation between the Ethiopian Institute of Architecture, Building Construction and City Development (EiABC) in Ethiopia and the Professorship of Dirk E. Hebel of Architecture and Construction at the Singapore-ETH Centre for Global Environmental Sustainability and the Future Cities Laboratory (FCL) in Singapore.

Professor Dr. Elias Yitbarek initiated the project in 2010 as part of his work at the Chair of Housing at the EiABC and has secured funding from the Arthur Waser Foundation for a pilot project in 2011, with the support of the North-South Centre of ETH Zurich, Barbara Becker and the ETH Foundation, Nathalie Fontana. The pilot was regarded as a great success. It involved building two housing units located approximately 250km south of the capital Addis Ababa, and experimentation with local building materials combined with new building techniques and autonomous operating energy supply units. This success convinced the Arthur Waser Foundation to continue the engagement with the two universities and enlarge the scope of the work to include questions of capacity building, academic exchange with local schools and industry and the transfer of knowledge to a wide academic and non-academic audience in Africa.

Lara Davis, PhD researcher working under the supervision of Dirk E. Hebel at the ETH in Zurich, will fully concentrate her work on the development of technical solutions in earthen masonry systems, which address challenges posed by environment conditions, as well as constraints in available building materials and skilled labor. She will also look into robustly co-designed training methodologies, which target maximum cultural relevance, mechanisms for knowledge exchange, and methods for sustainable technology transfer with long-term viability. Next to the strong focus on applied research, where full scale housing units will be built, two PhD students at the EiABC under the guidance of Dr. Elias Yitbarek will work on soft impact factors such as health issues, socio-cultural frameworks, communication strategies and participation models in order to guarantee a long lasting anchoring of the project in rural regions of Ethiopia as well as building up curricula for the academic impact in schools and universities.

The ETH Zurich and the EiABC in Addis Ababa have a long history of academic collaboration. The SRDU research can be seen as the sister project of the Sustainable Urban Dwelling Unit: SUDU. The project, initiated in 2010 by Dirk E. Hebel, who was at that time the Scientific Director of EiABC, investigated the stock and flow model of building materials in Ethiopia and introduced new building techniques and material applications such as earth masonry vaulting together with Prof. Philippe Block and Lara Davis of ETH Zurich, in order to minimize the dependency of building material import in Ethiopia. The project got well know also in Ethiopia and beyond and set the tone for further investigations also in rural areas. With the funding of Arthur Waser Foundation, ETH and EiABC have the chance to further strengthen their research collaboration by understanding the build environment as a complex and open system, ranging from the urban territory to the neighborhood scale and with it the question of material application, considering economic, ecological, social and aesthetic values for a future urbanization of developing territories world wide.

Waste is usually defined as unwanted or useless material, which is the product of a linear utilization process.

Endless stocks of material are already in the cities regarded as waste. Making this (re-) source available, the value-chains of construction products and materials have a great potential for increased ecological and economic efficiency, and with it minimizing global material flows. Waste products, but also local available materials which were not used in the construction sector yet, need to be recognized as basic elements of the urban creation process. Their use, re-use, and potential for re-placement of other materials are key factors for creating identity, resource efficiency, and new added values to a specific urban system. Analyzing potentials of waste products as a resource for new construction materials and products will be key factors of this research. The understanding of the term “waste” needs to be extended to such materials which were not seen as construction materials yet, or which were seen as backward-oriented, cheap or useless. Waste resources must be analyzed and quantified in similar terms and standards as natural resources. With this analysis, comparative strategies can be implemented. In addition, up-cycling strategies have to be followed, designing new products in such a way, that projected further life-cycles are already incorporated.

In the United_Bottle project, a regular waste product like the PET bottle becomes a new building material, (Source: United_Bottle Group Zürich, 2007-ongoing)

Soil is a natural body consisting of layers (soil horizons) of primarily mineral constituents of variable thicknesses, which differ from the parent materials in their texture, structure, consistence, color, chemical, biological and other physical characteristics.[1]

Sustainable construction requires an integrative thinking of various possible local available materials, skills and know-how. There is a need to enhance vernacular construction and material knowledge to cope with the dramatic need for new urban dwellings. This knowledge must be based on integrative modes of thinking, combining design, construction, building physics, sociology, energy, ecology and economy. If local construction materials and their application could be made available to the wide public in developing territories, local value chains could be build up using a very low-cost and easy to obtain material.[2]

Straw belongs to the family of grasses. Grasses are plants, which typically have one seed leaf and continue to grow with narrow leaves from their base. The family includes “true grasses”, sedges and rushes. The Chair of Architecture and Construction at FCL is mostly interested in true grasses such as bamboo and cerials, since their characteristics show a high potential for taking tensile stress.

The Chair of Architecture and Construction at FCL Singapore started a research project together with the Bauhaus University in Weimar and the Ethiopian Institute of Architecture, Building Construction and City Development in Addis Ababa focusing on straw panel building technology. New settlements are emerging in developing territories almost every day, growing fast into urban conglomerates. One of the biggest problems in emerging cities is next to infrastructure measurements, available and affordable building materials and techniques for shelter production. The research project is focusing on the development of innovative and low-weight construction materials for emerging cities in developing territories, based on agricultural “waste” products like straw.

Straw panels and first ideas about load-bearing applications (Source: Prof. Dr. Dirk Donath)

The company STRAWTEC© in Berlin, Germany developed over the last years a production system for pressed straw panels. Through heat, the natural starch in the straw is activated and functions as natural glue without any other chemical additions. So far, the panels are only used as non-bearing structural elements. The project will investigate possibilities to develop the product and invent construction methods for load bearing applications. Presumed a positive research outcome, this innovative method could be applied in developing territories, which are economically agricultural based, including India, China and Indonesia.

Bamboo belongs to the family of grasses. Grasses are plants, which typically have one seed leaf and continue to grow with narrow leaves from their base. The family includes “true grasses”, sedges and rushes. The Chair of Architecture and Construction at FCL is mostly interested in true grasses such as bamboo and cerials, since their characteristics show a high potential for taking tensile stress.

Looking at available local resources, the “magic triangle” contains one of the most neglected building materials in the world so far: Bamboo. Most developing territories today with an ever-growing speed of population increase and with it an ever-increasing need for housing are to be found in a belt around the equator. And also here, bamboo is usually the fastest growing, affordable and local available natural resource, which has outstanding constructive qualities. Bamboo grows much faster than wood and is usually available in great quantities and it is easy to obtain. It is also known for its unrivalled capacity to capture carbon and could therefore play an important role in reducing CO2 emissions world wide. Developing territories around the equator belt could use this capacity even as an income source, selling CO2 certificates in a global market.

Global natural habitat of bamboo

Bamboo is extremely resistant to tensile stress and is therefore one of nature`s most extreme products. In principle, bamboo is with regard to its mechanical-technological properties superior to timber and even to reinforcement steel in terms of the ratio of liveload and deadweight [1]. The “hinterland” of Singapore offers a huge potential for developing new ideas to use bamboo not only in rod structures but also as composite material in an added value chain mentality, which will help developing territories to build up supply chains domestically and therefore reduce their dependencies on imported building materials. New technologies of bamboo composite productions allow for a new view on already elaborated methodologies of the 1950`ies and 60`ies by the US Naval Civil Engineering Laboratory [2] and the Clemson Agricultural College [3]. The research will focus to develop new products, based on bamboo as one of the most efficient and fastest growing resources in the equator belt.

We travel to Addis Ababa, the capital of Ethiopia. While modern architecture dominates the cities, the rural areas are traditionally characterized by “tukuls” – round, simple loam houses. A contemporary reinterpretation of this construction method is being developed as part of the Building Week: The “Tukul 2.0” combines the traditional architecture of Ethiopia with rammed earth technologies known in Europe.

In collaboration with students from the School of Built Environment (formerly EiABC) at Addis Ababa University, prototypes will be created that enable a more robust, durable and yet simple construction method. The focus is on the intercultural exchange of knowledge between Ethiopian and German students.

First orientation meeting: 7 May 2025, 3:00 PM, Bldg. 11.40 Room 26

Excursion one week in the period 28.09.25 to 12.10.2025