Guangming Village

Guangming Village is located in Ludian County, Yunnan Province, China. A total of 90% of the local houses in Guangming Village were rammed earth with sloped roofs. Rammed earth construction has a long history in China, particularly in rural Yunnan. Mud was the main material used in traditional architecture because this component is inexpensive and accessible as well as exhibits impressive thermal performance.

Guangming Village was hit by a shallow earthquake with a magnitude of 6.1 on 3 August 2014. After the earthquake, villagers lost their confidence in the local traditional rammed earth buildings, 90% of which were damaged during the earthquake. Therefore, most villagers preferred to build brick–concrete houses during the reconstruction period. Other commercial solutions such as light-weight steel buildings were also provided to the local residents. However, given the increase in reconstruction needs and the poor traffic conditions after the earthquake, the price of building materials rapidly increased and became unaffordable for most local villagers. They have to borrow money or apply for loans to complete the reconstruction. The debt after the disaster was an economic and psychological burden to the villagers. A considerable number of them tried to find jobs in urban areas to earn a substantial amount of money. Elderly and children were left in the village.

Therefore, this project aims to innovate the traditional rammed earth building technology and provide a safe, economical, simple, and sustainable reconstruction strategy that the villagers can afford, own, and pass on. This scientific and systematic reconstruction strategy and the craftsman training programme will also provide guidance for national reconstruction policies and rammed earth building standards in the future.

Building design and technology innovation
This project was organized and conducted by the team of the One University One Village (1U1V) rural programme of CUHK, which was donated by Chan Cheung Mun Chung Charitable Fund. Furthermore, the project was supported by Kunming University of Science and Technology (KMUST) and the University of Cambridge in terms of building structure, seismic performance improvement, and testing.

A prototype house has been built for an aged couple to validate the technology and building performance of the innovative rammed-earth building system. According to the situation of Guangming Village, the “3L“(local technology, local materials, and local labor) reconstruction strategies were used in the project to provide an endogenous and sustainable solution. The traditional rammed earth technology was improved by using “high science and appropriate technology” theory, which mainly focuses on seismic capacity, thermal comfort, daylighting, and cost efficiency.

Within a limited land, the design is integrated with semi-outdoor spaces to provide a comfortable and artistic living environment for the aged couple. The semi-outdoor atrium with skylight and cross ventilation is bright and comfortable. Double-glazed windows and insulated roof are used to improve the thermal performance of the building.

To improve the seismic performance, we used an appropriate size of concrete foundation with a correct cement mortar to enhance the integrity of the foundation of the house. The concrete ring beams and the floor were used to improve structural integrity and avoid vertical cracking. The soil of the site was examined in the lab and adjusted properly with sand and straw to avoid cracks and make the wall solid. Aluminum alloy formwork and electrical rammed tool has been used instead of wood formwork to make the wall substantially compact and smooth.

Furthermore, a shaking-table test has been conducted to validate the seismic performance of the innovated technology. The result corroborates that the seismic performance of the rammed earth building has been significantly improved, thereby meeting the local seismic codes perfectly.

Outcome
The building design is simple and easy to implement based on the current technology and the ability of villagers. Multi-functional spaces that can be used as storage rooms, guest rooms, or workplaces have been provided to adapt to the villagers’ lifestyles. The prototype houses have reasonable storey height and window size because of the improvement of wall strength and building structure. The building shape and facade are simple and tidy. The indoor environment is spacious, bright, clean, and well ventilated. Consequently, the design decoupled the relationship between rammed earth building and backwardness.

The innovative technologies ensured the safety of the rammed earth house. We just improve the traditional technology with simple materials and tools rather than copying foreign technology. Therefore, the technology is simple, comprehensible, and affordable to the villagers. Our team donated the formwork and rammer to the villagers for them to possess this technology and pass it on. In other words, we protected the local traditional construction method and lifestyle by improving its building performance with a simple strategy and the empowerment of the local residents.

In the environmental dimension, the embodied energy and environmental impact of the houses are minimized. Good thermal and daylighting performance guaranteed low operating energy consumption.

In the economic dimension, construction and operation costs have been minimized to be affordable to the local residents. They carry out the construction mainly with manpower and simple tools. In the future, improvement and maintenance can be done with ease. Owning this technology can also be a way of earning a livelihood.

In the social dimension, the local residents are respected and fully engaged in the whole reconstruction process. Multidisciplinary university resources are in full support of rural reconstruction. The local government is also involved to examine and explore this new sustainable way of rural reconstruction. Rural residents are empowered and are given a chance to collaborate with different stakeholders of rural constructions. The result verified an appropriated solution of the local reconstruction that will provide references for national reconstruction policies and earth-building seismic standards in the future.

This project won the AR House awards 2017 and the World Building of the Year of the World Architecture Festival 2017. Numerous local residents, government officers, and rural constructors visited the demonstration project and gave positive comments. The team received many invitations to guide the anti-seismic rammed earth building project and organize craftsman training programmes in other villages. The first craftsmen training class has been organized in KMUST for both male and female villagers from Guangming Village. Several new rural construction projects have been launched and started in Yunnan and Sichuan provinces.

Currently, trained craftsmen of Guangming Village are hired to work with 1U1V team in another rural construction project site in Dabaiyi Village, Yunnan Province. Moreover, a Terra Center will be built in KMUST to support the research and testing of earth architecture in Southwest China. Based on this center, considerable research and international academic exchange will be conducted. Books and guidelines will be published to systematically document this method and provide references for national reconstruction policies and seismic standards for buildings made of earth materials in the future. This strategy will also provide guidance for local reconstruction policies and rammed-earth building standards.