Thin Vaulting: Rwanda National Cricket Stadium

 


YorkshireTea_RwandaCricket_25.10.17 - Team Yorkshire Tea playing at the Rwandan Cricket Stadium - credit Jonathan Gregson_preview
Team Yorkshire Tea playing at the Rwandan Cricket Stadium (Photo: Jonathan Gregson)

This project is part of a 5-year collaboration between Light Earth Designs and the Rwanda Cricket Stadium Foundation, which focuses on how Rwanda can transition away from a purely agricultural economy using local home-grown, labour-intensive construction techniques, thereby avoiding imports, lowering carbon, and building a skilled workforce.

The primary enclosure of the cricket stadium, the vaults, adapts ancient Mediterranean tile-vaulting (using compressed soil-cement tiles) to a moderately active seismic area by using geogrid reinforcing in the layers and bearing the springing points of the doubly curved vaults on the ground.  The vaults follow the natural resolution of forces toward the ground, closely mimicking the parabolic geometry of a bouncing ball and evoking the cherished hilly topography of Rwanda. The masonry vaults are completely in compression, allowing the use of a simple layered thin shell composite of low strength tiles.

The tiles, which are hydraulically pressed with a small addition of cement and do not require firing, are produced on site using local soil and a combination of skilled and unskilled local labor. They are laid in layers onto a temporary timber skeleton and span up to 16m. A geogrid (developed by architectural and engineering researchers at Cambridge University) is added to give some seismic protection. The shells are waterproofed and topped with local broken granite (found everywhere across the country) to help the structure blend in with its surrounding as well as to add weight and stability.

Simple, efficient, and thin concrete tables are inserted into the vaults, providing space for the more enclosed functions: the service areas, the changing rooms, an office and a restaurant.  These tables are topped with natural Rwandan agro-waste-fired tiles made of commonly found wetland clay. The open mezzanines -a bar and a clubhouse -enjoy wonderful raised clear panoramic views over the Oval and wetland valley beyond.

Bricks are used to define edges and spaces -often laid in a perforated bond -allowing the breeze and light to filter through. These bricks are sourced from enterprises set up by Swiss NGO SKAT Consulting, and are also low carbon agro-waste-fired bricks manufactured using high efficiency kilns, further reducing embedded energy and carbon.  Waste stone from Rwandan granite flooring and worktops are used for flooring. The plywood rectangles used to press the tiles are reused as countertops while timber and plywood from the vault formwork is made into joinery and doors, ensuring that a maximum of waste material goes into primary production.  Local slate is configured to allow rain water to permeate and infiltrate the soil.  Retaining walls are either local granite boulders or are hollow to encourage planting.

The building grows out of the cut soil banking that was formed as the pitch was levelled, thus becoming part of the landscape. The banking creates a wonderful natural amphitheater with great views to the pitch and the wetland valley beyond.  Whilst the language of the building speaks about progression and dynamism through extreme structural efficiency, the materials speak of the natural, the hand made, and the human. It is a building made by Rwandans using Rwandan materials.

The design builds on vault design and research by Michael Ramage at the University of Cambridge Centre for Natural Material Innovation alongside Ana Gatóo and Wesam Al Asali, and extends the work of Ramage with John Ochsendorf (MIT) and Matt DeJong (Cambridge).

30- Rwanda_National_Cricket_Stadium-Credit Paul Broadie_Yorkshire Tea
(Photo Paul Broadie)

Peter Rich Architects with Michael Ramage and John Ochsendorf pioneered soil tiled vaulting at the Mapungubwe Interpretation Centre (SA).  Light Earth Designs (Tim Hall, Ramage, and Rich) continued with the Earth Pavilion (UK), FR2 offices for Joseph Ritchie (Chicago, USA) and have undertaken research in the application of geogrids in seismic zones conducted at the University of Cambridge.

The vault construction proposes a mix of low skilled and skilled worker teams. The teams are trained by an expert mason, in this case James Bellamy (a mason from New Zealand). The tiles are laid with the inner layer resting on a temporary formwork (made of timber and scaffold) that allows the form to take shape. The inner layer of tiles is laid upwards from the perimeter and stays in place through the use of a quick setting gypsum mortar. As the first layer continues, successive layers of tiles are laid in a thin lime and cement mortar inlaid with geogrid. The number of layers is determined by the vault span (in this case up to six layers with a large span of 16m). The tiles are topped with a screed and waterproofed with a torched sheet membrane. On top of this a network of geogrid is laid with a composite granite stone and lime/cement/sand mortar mix.

14-Light Earth Designs Rwanda Cricket Staduim 3
(Light Earth Designs)

The imperfections are celebrated – they are human and beautiful – and when combined with the layering of natural textures the building becomes imbues and celebrates this wonderful place.

Rwanda cricket stadium poster
(Light Earth Designs)
Imprimir
(Light Earth Designs)

All Pictures © Light EarthDesigns unless otherwise noted: https://tinyurl.com/yb5t27qv

Project Location

  • Gahanga, Kigali, Rwanda

Client

  • Rwanda Cricket Stadium Foundation

Light Earth Designs team

  • Tim Hall -Partner and lead
  • Michael Ramage -Partner and vaulting lead
  • Ana Gatóo -Project lead architectural engineer; on site lead
  • Ben Veyrac -Project architect at tender and architect
  • Wesam Al Asali -formwork design
  • Anton Larsen –architect
  • Marco Groenstege -architectural technician
  • Oliver Hudson -engineering support
  • Killian Doherty -project inception architect

Contractor

  • Roko Construction, Kigali
  • James Bellamy, Vault Specialist

This post was adapted from a press release kindly provided by Michael Ramage of Light Earth Designs. For more information, please visit:  https://www.ribaj.com/buildings/cricket-pavilion-light-earth-designs-rwanda

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