The primary structure is made of walls of packed tires laid out on a 100’ x 30’ footprint. Tire walls are 7’ high and follow curved patterns creating a geometrically stable shape where no buttressing is needed. In addition, it allows to avoid the presence of sharp corners where stresses would accumulate in the event of an earthquake, thus creating weak spots in the structure.
The building is built along a rammed earth tire retaining wall following the West-East axis. This means that the tires located on the side of the building are also part of the retaining wall and thus need to be larger than the ones on the rest of the building in order to resist the lateral earth pressure.
Tires are filled with the earth taken out during the excavation stage, and non-biodegradable waste. The tires are stacked in a running-bond pattern to maximize interlocking between courses. Additionally, horizontal rebars are laid between two courses about half way up in the wall in order to stiffen the wall against lateral forces during the construction stage.
A 6” deep concrete bond beam is poured on top of the last course of tires in order to tie the whole primary structure together and facilitate the connection with the concrete roof. However, on the side, the retaining wall needs to be higher than the building walls and that is why the wall continues above the level of the bond beam with smaller tires. The upper part of the retaining wall is covered with ferrocement for rainwater collection purposes.
Walls are founded on trenches filled with tamped down gravel and the first two courses of tires are filled with gravel. This foundation provides a solid footing for the walls while preventing any water infiltration via capillary action.
Similarly, the 4” thick concrete slab inside the building rooms is poured on top of a 4” thick layer of gravel in order to avoid any contact between the concrete and ground water. The patio slab consists of a pavestone ground laid down on a 4” thick layer of sand enabling water drainage.
The roof of each individual room consists of a 4” thick reinforced concrete dome tied into the bond beam. Glass-bricks (2 bottoms of glass bottles tied together) are tied into the reinforcement and act as skylights. The patio roof is made with paper-cement fiber corrugated panels supported by metal rafters and purlins which rest on two lines of concrete columns. The columns along the line sit on the bond beam while the South ones have their own individual concrete pads.
Separate outdoor rooms are created between the building rooms by adding concrete walls in the patio space.
Door frames are made with concrete columns carrying concrete arches. The columns are founded on rectangular footings and cast against the tires therefore providing a lateral restraint to the walls. The concrete arches are tied into the bond beam in order to limit the impact of the door openings on the global stability of the structure. Window frames are built in a very similar way.
Wall finishes (interior and exterior) are made of cob (earth + sand +straw) applied against the tire walls where nails have been added to enhance the cob adherence. The cob fills in the voids between tires and creates a flat surface. On the inside, it is covered by two layers of plaster: a form coat (cement + lime + coarse sand) and a final coat (cement + lime + fine sharp sand).
The interior ceiling plasters are the same as the one used on the walls. Exterior ceiling plaster consists of cement-based render and sealant paint.
Rainwater is collected on the concrete roof through awnings and sculpted gutters guiding the water towards a main concrete gutter located along the retaining wall on the Northeast of the building. Additionally, rainwater falling on the inclined patio roof is guided towards a metal gutter along the South edge of the roof before joining the main concrete gutter mentioned above.
Regarding soil drainage strategy, any accumulation of water behind the retaining wall could jeopardize the viability of the structure. In order to avoid this, a plastic sheeting and a layer of sand are applied between the tires and the retained earth. They prevent infiltrations through the wall and instead drive any potential water down to a drainage pipe full of gravel located at the bottom of the wall. This pipe slopes towards the Northeast corner of the building where it is connected to a concrete drain tile crossing the retaining wall.
Oval Tire Classrooms
The primary structure is made of walls of packed tires laid out on a 100’ x 30’ footprint. Tire walls are 7’ high and follow curved patterns creating a geometrically stable shape where no buttressing is needed. In addition, it allows to avoid the presence of sharp corners where stresses would accumulate in the event of an earthquake, thus creating weak spots in the structure.
The building is built along a rammed earth tire retaining wall following the West-East axis. This means that the tires located on the side of the building are also part of the retaining wall and thus need to be larger than the ones on the rest of the building in order to resist the lateral earth pressure.
Tires are filled with the earth taken out during the excavation stage, and non-biodegradable waste. The tires are stacked in a running-bond pattern to maximize interlocking between courses. Additionally, horizontal rebars are laid between two courses about half way up in the wall in order to stiffen the wall against lateral forces during the construction stage.
A 6” deep concrete bond beam is poured on top of the last course of tires in order to tie the whole primary structure together and facilitate the connection with the concrete roof. However, on the side, the retaining wall needs to be higher than the building walls and that is why the wall continues above the level of the bond beam with smaller tires. The upper part of the retaining wall is covered with ferrocement for rainwater collection purposes.
Walls are founded on trenches filled with tamped down gravel and the first two courses of tires are filled with gravel. This foundation provides a solid footing for the walls while preventing any water infiltration via capillary action.
Similarly, the 4” thick concrete slab inside the building rooms is poured on top of a 4” thick layer of gravel in order to avoid any contact between the concrete and ground water. The patio slab consists of a pavestone ground laid down on a 4” thick layer of sand enabling water drainage.
The roof of each individual room consists of a 4” thick reinforced concrete dome tied into the bond beam. Glass-bricks (2 bottoms of glass bottles tied together) are tied into the reinforcement and act as skylights. The patio roof is made with paper-cement fiber corrugated panels supported by metal rafters and purlins which rest on two lines of concrete columns. The columns along the line sit on the bond beam while the South ones have their own individual concrete pads.
Separate outdoor rooms are created between the building rooms by adding concrete walls in the patio space.
Door frames are made with concrete columns carrying concrete arches. The columns are founded on rectangular footings and cast against the tires therefore providing a lateral restraint to the walls. The concrete arches are tied into the bond beam in order to limit the impact of the door openings on the global stability of the structure. Window frames are built in a very similar way.
Wall finishes (interior and exterior) are made of cob (earth + sand +straw) applied against the tire walls where nails have been added to enhance the cob adherence. The cob fills in the voids between tires and creates a flat surface. On the inside, it is covered by two layers of plaster: a form coat (cement + lime + coarse sand) and a final coat (cement + lime + fine sharp sand).
The interior ceiling plasters are the same as the one used on the walls. Exterior ceiling plaster consists of cement-based render and sealant paint.
Rainwater is collected on the concrete roof through awnings and sculpted gutters guiding the water towards a main concrete gutter located along the retaining wall on the Northeast of the building. Additionally, rainwater falling on the inclined patio roof is guided towards a metal gutter along the South edge of the roof before joining the main concrete gutter mentioned above.
Regarding soil drainage strategy, any accumulation of water behind the retaining wall could jeopardize the viability of the structure. In order to avoid this, a plastic sheeting and a layer of sand are applied between the tires and the retained earth. They prevent infiltrations through the wall and instead drive any potential water down to a drainage pipe full of gravel located at the bottom of the wall. This pipe slopes towards the Northeast corner of the building where it is connected to a concrete drain tile crossing the retaining wall.
Full Process -
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