ALTERNATIVE TECHNOLOGIES                


CUBE - ON - VERTEX STRUCTURES

Appropriate Technology, often limited to Replacement Technology, results in substitution of one building material with another. The attempt in the creation of this structure was to design an all-encompassing system that examined the "Use of appropriate building materials" as also the "Fundamental approach to design of structure". The basic form utilised here is a regular cube, with only variance in application. A regular cube has six faces, each tending to bend towards its centre, causing an inward pull on each of the adjoining planes

When the same is rotated and placed on its vertex, a whole range of structural and design options open up. The inclined faces of the "Cube on Vertex" behave as deep beams, resulting in a structure which utilises the full potential of the form. Consequently, each face of the "Cube on Vertex" becomes a supportive plate for the adjacent face. Removal of the three lower surfaces of the "Cube on Vertex" results in hexagonal plan which further unravels a multitude of architectural design solutions.


The problem, however, lies in executing this form using RCC. Use of RCC is limited by the fact that it has to be poured over a form work in a plastic state and the allowed to set. Clearly, if RCC was to be used for this structure, this form would not be a viable proposition. Rather than give up a highly versatile concept, we at Anangpur Building Centre decided to critically rationalise materials and their conventional application-individually and as used in unison-to generate a holistic application.

Logically, therefore, one had to explore a "system of dry assembly". A skeleton comprising of 8"X8"X6'-0" prismoidal trussed beams with corner plates was assembled using a cube of size 8"X8"X8" as connector . The entire skeletal structure was bolted together through corner plates. Using this components, the three side of a cube, laid flat on one face, are assembled as illustrated below. A simple flipping of this assembly around one of the points resulted in the desired form that could be easily lifted and placed over stub columns.


With these components and the basic assembly system one can now let the imagination take over, generating a variety of options. The "Cube on Vertex" can be truncated at various levels from the top as well as the lower levels . It can also be made larger by addition of components to house diverse functions ranging from small units, as in this case, to amphitheaters and swimming pools. Another simple structural system that can easily be put together by just using the two sides of the square is an A-Frame . Components can further be pulled out at different junctions and levels for construction of upper storeys and terraces .

Cladding the skeleton was the next issue that was tackled. The conveniently available option was to use tiles over a sub-structure of purlins. In this case, an additional sub-structure would be required for false ceiling for good interior finish. Alternatively, Medium Density Fibre Board(MDF)/ Cement Bonded Wood-chip Board could also be used with purlins nailed directly to it. Tiles can then be nailed on the purlins. This composite use would result in saving the cost of sub-structure for the false ceiling. Instead of going in for these options, we decided to use 'Exfoliated vermiculite ferrocrete panels', which would do away with the need for purlins and a false roof besides providing additional thermal insulation. Exfoliated vermiculite, i.e. mica exfoliated at the temperature of about 800 Celsius, is a good insulating material generally used for making furnace bricks.

Distance between the components determined the length of the panels and the width was governed by the weight of each panel. It was limited to 50 Kg to ensure ease in lifting and placement of panels on the structure by maximum three persons. The panels were 50mm thick with a 20mm layer of an exfoliated vermiculite-cement mix sandwiched between two 15mm layers of ferrocrete reinforced using extended 'U' ribs of 40mm depth made of welded steel mesh . Hexagonal chicken mesh was used in the two layers of ferrocrete and exfoliated vermiculite mix. The panels are held to the skeletal structure by clamps welded at the end. For the final exterior finish, Teracrete tiles were used. These were nailed onto the panels through two adjacent holes drilled in the tiles. Other option could include the conventional Mangalore tiles fixed in a similar manner, sand face plaster or any other desired finish.

The walls have been built using blocks with permanent finishes, as propagated by the Anangpur Building Centre. This includes the Ram Lochan tile blocks and the Hollow-core blocks. These walling systems employ the concept of "Surface Engineering" by using an impervious diaphragm on the exterior surface exposed to weathering with a lean back up material constituting the main body of the blocks.

The "process of rationalisation" was not restricted to the roof and walls only but every aspect of the building was subject to a deep analytical scrutiny. For instance, eccentric arched foundations were used. These provide for a more economical and sound foundation principle by combining the best of structural systems, such as the 'arch' and the 'bracket', which generally find application in superstructures only. Therefore, by looking at the entire structure holistically and analysing "every material to use it at the lowest level that it could best perform at" the resultant structure was cost effective, quick and easy to construct while being aesthetically pleasing.

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