SUBJECT: BASIC TECHNOLOGY
TERM: 3RD TERM
TOPIC: SETTING OUT
Anybody wishing to construct a building usually first consult an architect on the need for a building and the type of building wanted. An architectural design is sent to the structural engineer, who determines and specifies the strength and type of building material to be used. The quantity surveyor studies the working drawing of the proposed building determines the cost of materials, labour and workmanship. Finally, a construction company wins the contract for the construction of the building.
Building construction start with setting out
Setting out is, therefore, a process of driving wooden pegs into the ground here and there, in a manner that agrees with the dimensions of the building specified on the architect’s drawings.
Setting out is also the process of transferring with high degree of skill and accuracy, the detail of the foundation plan from the drawing sheet on the ground, with pegs, lines and tapes.
Working drawings include following drawings:
The following tools are used for setting out
When the concrete footing for the foundation has been cast and cured lines for the thickness of the wall are run and plumbed down to the concrete footing and the first course of the concrete block wall is laid.
When foundation plan for a building has been transferred on to the site, by way of setting out, excavation begins. For very big structures like stadium or a multi-storey building, the trenches for the column foundation or wall foundation can be mechanically excavated. Holes are mechanically bored where bored piled foundation has been recommended.
This is the process of supporting the walls of the excavated pit with timber, for the purpose of safety.
CONCRETE AND ITS MATERIALS
Concrete consists of a matrix or binding material (cement), fine aggregate (sand) and coarse aggregate (stone) mixed thoroughly with water. Concrete, therefore, is a composite material in which a binding material mixed with water o solidification binds the inert materials – the particles of well- graded fine and coarse aggregates. Green concrete is used in the construction of footings, foundations, slabs, columns, lintels, beams, steps, and walls. It resists decay moisture and corrosion from acids. REINFORCED concretes are concrete having steel rods or welding wire mesh.
A good concrete should be strong, durable, hard, dense, non-porous, fire resisting and economical.
Read more on setting out (NERDC Basic Tech. for JSS2 page123-126 )
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