Foundation work: Laying concrete, piling, and base structures
Foundation work establishes the building’s load-bearing base, ensuring long-term stability through concrete pouring, pile driving, and base structure assembly. These steps follow site preparation and demand precision to handle soil conditions and structural loads.
Laying Concrete
Concrete laying forms footings, slabs, and pads that spread building weight evenly. Workers set formwork timber or steel molds braced to exact dimensions—then place rebar cages for tensile strength. Ready-mix trucks pump concrete (typically M25-M40 grade) into forms, vibrated to remove air pockets and leveled with screeds. Curing with wet hessian or compounds lasts 7-14 days, reaching 70% strength before loads apply. In Dubai’s heat, retarders prevent flash setting, while expansion joints accommodate thermal shifts.
Piling
Piling transfers loads to deeper, stable strata when surface soils prove weak, common in UAE’s sabkha layers. Bored piles drill 20-40m deep via rotary rigs, inserting steel casings and tremie pipes for underwater concreting to avoid segregation. Driven precast piles hammer in using diesel rigs, relying on end-bearing or friction. Pile caps—thick RC blocks—tie groups of 4-9 piles, with ground beams linking caps for uniform load paths. Testing via PDA or static loads verifies 200-500 tons capacity per pile.
Base Structures
Base structures include grade beams, raft slabs, or plinth levels tying the foundation system. Ground beams span pile caps, supporting walls and preventing differential settlement. Raft foundations—a continuous slab suit poor soils, stiffened with ribs and underlaid by friction piles. Plinth beams elevate floors above grade, integrating waterproofing membranes and damp-proof courses. Formwork strips after 21 days, followed by backfilling with compacted granular fill.
Process Sequence
- Survey sets centerlines and levels.
- Excavate to design depth, install piling if needed.
- Place formwork, rebar, and pour concrete.
- Cure, test cubes for compliance.
- Construct tie beams and backfill.