How Raft foundation is constructed

This article is about raft foundation construction for a building. Raft foundation is always constructed for multistory buildings or building with heavy loads.

 

Step #1

In The first step surveyor has to do setting out for excavation and once survey is done then excavation to be done to the required level as per approved shop drawings.

During excavation all safety measure to be taken, the whole area to be barricaded and everyone has to use PPE at site.

Step #2

Once the excavation has been reached the final stage then the surface to be compacted with plate compacter if the area is small in case it is not possible to use the roller compacter, but 95% compaction must be ensured through compaction test.

Step#3

After getting satisfactory results of compaction test, 75mm or 100 mm blinding concrete is placed. Blinding concreter must be garde20/20 SRC (Sulphate Resisting concrete)

the purpose of blinding concrete is providing a solid and even surface for the reinforcement of raft foundation.

Curing polythene sheets shall be place immediately after finishing and then after setting of the concrete it shall be replaced with hessian cloth and should be kept wet until the surface gets completely dried.

After drying the blinding surface water proofing of surface shall be carried out as per approved specification.

Step#4

After water proofing proper planning to  be done for the shuttering work, all material shall be kept on a plate form and steel bars to be installed as per approved shop drawings the surrounding. all working space to be kept neat & clean to avoid accidents at site.

After the reinforcement work is completed the contractor has to get it approved from the supervision consultants for pouring the concrete.

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