Grid Slab:
A Grid slab is a type of building material that has two directional reinforcement on the outside of the material giving it the shap of the pockets on a waffle.
Features of the Grid Slab:
1. They are used on flat sites.2. No beam excavation is requied.
3. No controlled or rolled fill is used.
4. Cardboard slab panel/void formers are used.
5. Slab panels are on 1 metre grids (approximately)
6. Trench mesh or individual bars can be used.
7. Slab thickness is 85-100mm wide.
8. Internal beams are 100-200mm wide.
9. There is minimal concrete volume.
10. No beam down drag from clay (above ground slab) occurs.
11. Shrinkage of slab is lower than stiffened rafts and footing slabs.
12. They use 30% less concrete than a stiffened raft.
13. They use 20% less steel than a stiffened raft.
Construction:
1. Grids are generally limited to the interior of a slab, leaving one or two of the form out to create a solid fill around the supports.2. The solid fills provide the strength requied for shear transfer to the supports.
3. The fills also reduce the compression stresses at the floor around the supports, thus avoiding the necessity of bottom reinforcement in this region.
4. Picture illustrate typical grid construction using unbounded tendons.
5. A ligth top mesh over the grid is generally the only top reinforcement at the interior of the floor panels.
Benefits:
1. Flexible2. Relatively light, therefore less foundation costs and longer spans are economic
3. Speed of contruction
4. Fairly slim floor depth
5. Robustness
6. Excellent vibration control
7. Good for service integration
8. Durable finishes
9. Fire resistance