The RCSF is not only building a future for Cricket in Rwanda, but is facilitating reconciliation, and the rebuilding of communities through the essential values of cricket. Light Earth Designs- an integrated architectural and structural consultancy specialized in sustainable technologies and communities- takes us through the design of the first dedicated international cricket ground in Rwanda. In addition, LED gives a step by step guide of the ‘Thin Tile Vaulting’ construction process.
From The Architects:
In partnership with the Marylebone Cricket Club foundation (MCC) and the Rwandan Cricket Association an International standard cricket ground is planned for Rwanda. The facility will be non-profit and will operate a sport for all policy to ensure that Rwandans from all backgrounds can have access to cricket.
Rwanda Cricket Stadium Foundation (RCSF) Vision is to create:
A green and pleasant environment, where Rwandans of all ages can develop their cricket and use these skills into their wider lives. The intention is not to develop a cricket stadium in the conventional sense, but to create a unique place and setting that complements the beauty of the Rwandan landscape.
The development is conceived as an opportunity to empower and engage local people in need of work, skills and income through the use of local materials and high labour intensive construction techniques. It will be a benchmark in responsible and sustainable development and will provide the people of Rwanda with a unique and valuable asset.
The ground is to be constructed on a 4.5 hectare plot on the outskirts of Kigali. The project will be a multi-phased build, overseen in part by Light Earth Designs LLP, an award winning practice that is pioneering the use of Catalan timbrel vaulting using soil stabilised technology. The project develops the vault application for seismic areas – and proposes a series thin shell vaults of up 16 meter spans, giving spectators wide unobstructed views of the cricket oval.
The project is to be constructed using predominantly local labour sourced through a Rwandan Government led social protection programme, the Vision Umurenge Project. Households from the two poorest categories of the population (Ubudehe 1 and 2), will be targeted to work on the construction of the project. Therefore, it will create local green jobs, demonstrate the benefits and use of sustainable design and avails new building technologies to Rwanda’s construction industry.
Vaults Construction Process
Thin tile vaulting is a construction method that was developed around the Mediterranean and relies on the adhesion of several layers of overlapping tiles interconnected by fast drying mortar. This technique uses minimal material to create distinctive structural spans. Geogrid, a lightweight reinforcing material, has been added within the masonry to increase its tensile strength in case of earthquakes.
The main building is composed by three vaults made out of soil cement tiles. Below, it is detailed the construction process.
Step 1: Vaults´ plinths. The construction of the vaults start once the foundation and the structure of the three buildings is finalised. The first step is to build the concrete plinths for the three vaults. Each plinth has different dimensions according to the geometry of the vault These plinths made out of reinforced concrete will incorporate layers of geogrid that will then, be attached to the arches that will contain each vault.
Step 2: The guidework. Once the plinths have set, the construction of a guidework will begin. The guidework, made out of timber, will give the shape to the vault and its arches. The guidework for the arches will be supported by props. Due to the fast setting mortar used to join the soil cement tiles and to the technique, a proper formwork is not needed. This reduces noticeably labour and cost.
Step 3: The arches The arches are composed by layers of soil cement tiles, mortar and geogrid. As mentioned before, the geogrid has the function of giving tensile strength and therefore improving the performance of the masonry structure in case of the appearance of dynamic loads, as for example, earthquakes.
Each arch has different layers depending on the load carried from the vault.The process is repeated till we arrive to the adequate number of masonry layers. This depends on the loads carried from the vault. The number of geogrid layers will depend on the maximum tensile strength needed. The first course of tiles will be laid using fast setting mortar, which sets almost instantly, so the tiles can hold its own weight and the work can continue without the need of a formwork. All the other layers will be laid using an ordinary mortar.
After the first arch is built, or simultaneously, depending on the available labor, the next three arches will be built. These arches will support the corresponding vault.
Step 4: The vault . The vault will be constructed the same way as the arches, by layers of tiles, mortar and geo grid. The guide work will give the shape of the vault. The vault will have a bigger number of layers in its base due to an increased load. The number of layers will be determined by its dynamic and static loads. The process is repeated till we arrive to the adequate number of masonry layers. The number of geogrid layers will depend on the maximum tensile strength needed.
Once some rows have been laid, the next layer can start being built. The first layer will be laid with fast setting mortar and the rest of the layers with an ordinary one. After the construction of the first vault is finished, the same process will be done for the second and third vault, with a difference in the number of layers. The vaults will have a waterproofing layer on top of the last layer of soil cement tiles and will be finished with a layer of terracotta tiles.