Reinforced concrete upper floor options

-centering is the temporary platform (formwork ) on which cast in-situ concrete floors are constructed and supported until the concrete has sufficient strength to be self-supporting
-Self-centering is used to define those precast concrete floors that require no temporaray support
-Self-centring is used to define those precast concrete floors that require no temporary support
Self-centering concrete floors are precast in the manufacturers factory and are delivered to the building site where they are hoistd to the level of the floor and placed in position
-oce in position , they require no support other than the bearing of their ends on walls or beams

Monolithic reinforced concrete floor

• A monolithic reinforced concrete floor is one unbroken solid mass , between 100 and 300mm thick , cast in-situ and reinforced with steel reinforcing bars
• To support the concrete while it is still wet and plastic , and for few days after it has been placed , temporary support ( formwork or centering ) has to be used .
• Centering takes the form of rough timber boarding or steels sheets , supported on timber or steel beams and posts
• Steel reinforcement is laid out on top of the centering and raised 20mm or more aboce the centering by means of small concrete blocks (called spacers) , which are tied to the reinforcing bars with wire
• Wet concrete is then placed and spread over the reinforcement and the formwork , and it is compacted and levelled off.
• It is usual to design the floor so that it can safely span the least width of rooms
• Two opposite sides of the concrete are built into walls and brick partitions 1/2B each end.