The work shall cover furnishing and providing plain or reinforced concrete foundation placed in open excavation, in accordance with the approved drawings and these specifications.
Materials shall conform to Section 1000 of these specifications. All materials shall be of approved quality, tested, and conforming to relevant IS and MoRTH requirements before use at site.
Excavation for laying the foundation shall be carried out in accordance with MoRTH Clause 300. Open foundations shall be constructed only in dry conditions, and adequate dewatering arrangements shall be provided and maintained throughout the execution of work to ensure a stable and workable foundation bed.
The plan dimensions of the foundation shall be set out at the bottom of the foundation trench and checked with respect to the original reference line and axis. It shall be ensured that at no point the bearing surface is higher than the founding level shown on the drawing.
As per the drawing requirements, the Safe Bearing Capacity (SBC) of the foundation soil shall be ensured before commencement of the work by the in-house QC laboratory. All results shall be verified and approved prior to execution.
Where the bearing surface is earth, a layer of M15 concrete shall be provided below the foundation concrete. The minimum thickness of the lean concrete layer shall be 150 mm unless otherwise specified. No formwork is required for the lean concrete layer.
For foundation concrete work, side formwork shall be used. Formwork for the top of foundation concrete shall also be provided if the top has slopes steeper than 1 (vertical) to 3 (horizontal). When concrete is laid on a slope without top formwork, the slump shall be carefully controlled to ensure proper compaction without slippage of freshly placed concrete.
In certain cases, it may be necessary to construct the top formwork progressively as concreting proceeds up the slope. Reinforcement shall be placed strictly as shown in the approved drawings.
Before laying the lean concrete layer, the earth surface shall be thoroughly cleaned of all loose material and properly wetted. Care shall be taken to avoid muddy conditions. If any portion of the surface is found spoiled due to over-wetting, the same shall be removed and re-prepared before concreting.
| S.No | Activity | Inspection Required | Tests Required | Remarks |
|---|---|---|---|---|
| 1 | Approval of Previous Element of Structure | Yes | Yes | Jointly recorded |
| 2 | Layout & Survey | Yes | — | Joint survey and record |
| 3 | Formwork & Reinforcement Check | Yes | Yes | Jointly recorded |
| 4 | Concreting | Yes | — | Method control |
| 5 | Strength Check | Yes | Yes | QC check jointly |
✔ All safety measures shall be strictly implemented as per the approved EHS (Environment, Health & Safety) Plan.
