STRENGTHENING TECHNIQUES OF R.C. SLAB. INCREASE SLAB STRENGTH AFTER CONSTRUCTION
As a civil Engineer, always we face my types of problem in construction site. And after completing our project we are to take extra care on it. and some time we are to re-design different types of RCC member. so now i will discuss about slab redesign process and how we will increase its strength after many time later of construction.
There are many reinforcement techniques available depending on the strengthening purpose necessary. Any of those methods are discussed in detail in the sections below.
Why do we strengthen or redesign/reconstruct buildings?
- Increase in loads working.
- Faults, or dangerous construction.
- Corrosion with R.Steel or inadequate bar count.
- Concrete cracks, or less stress than construction stress.
- The foundation settlement is higher than the permissible.
STRENGTHENING OF R.C. SLABS
In some situations, and due to increasing the loads applied on slabs or their unsafe nature, or corrosion of the reinforcing steel bars or cracks in the slabs, one of the following solutions should be developed:
1. If the slab can not hold the negative moment, and the lower steel is adequate, a new concrete layer should be applied to the upper steel mesh.
2. When the slab can not hold the positive moment or if the dead load (which is applied to the slab) is much greater than the live load borne by the slab, a new concrete layer will be applied to the bottom of the slab.
To implement the above condition, following process have to complete.
1. Remove the cover on concrete.
2. Using a wire brush or a sand compressor to purify the reinforced steel plate.
3. Coating bars made from steel with an epoxy coating that prevents corrosion.
4. When a high percentage of corrosion is observed in steel bars, a new steel mesh must be added which is constructed according to the codes specifications.
5. The new reinforced steel mesh would then be mounted and vertically attached to the roof slab and horizontally fastened to the supporting beams using steel dowels.
6. Coating the concrete surface with an appropriate epoxy substance ensuring the bonding
between old and new concrete.
7. The concrete is poured to the necessary thickness until the epoxy dries out. To the concrete
should be applied additional materials which would reduce the shrinkage.