Types of Structure
1. Fame less - large paneled structures - External and Internal
wall panels - Floor and roof panels (of room single)
2. Framed buildings : Columns, beams & floor elements.
Stages of work in pre-casting
On -SITE : Open yard casting or covered but purely temporary or semi-permanent type of set-up with partly mechanized facilities.
Factors Influencing method of manufacture
The single and the total no of elements to be produced
1. The single of the element may decide the reinforcement of space for production as well as the capacity of the handling equipment is decided by the heorist element.
Desired rate of output: This will have direct bearing on the nf of moulds required degree of mechanization and need for accelerated method of curving.
3. Shape, type and construction features of these elements
Features such as special shares, projected reinforcement, required finish on the surface on single layer or multi layer largely influence the design of the mould and technical castings.
Horizontal casting techniques are favoured for curved elements, multi larged elements and element which require some particular finish vertical casting is favoured for single layer solid panel which require no special finish on their surfaces.
4. Facilities available in the production set u : An accelerated curing facility will result in quick turn over of mould which can be advantageously used. Machineries like over head gantry crane, will aid speedly production in handling.
5. Economic aspects : The cost of production should be minimum.
Both moulding and demoulding in horizontal position -External panel wall ; floor panes with protruded reinforcements, beams, columns, etc.
-Extra reinforcements to take ease of bending stresses.
Tilting Moulds :
Demoulding is carried out in almost vertical position. No extra reinforcement is necessary.
One end is hinged and the other end is lifted with the aid of a fack or lifting equipment.
Slip forming & Extrusion:
This method is achieved with a moving machine mould which forms the cross sectional shape of the element and the element hardening at the point where it is moulded. Precast pre stressed floor elements both solid & hollw are manufactured using this techniques.
Concrete laying - slips (Concrete buckets of various capacities)
Spreading - either manually or with a mechanical spreads.
Vibrating - with the help of shutter vibrates.
Screening - long & heavy wooden floats surface finishing - Travelling.
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