Structural Works

What the structure must hand over to the other trades

Every other package is built against the structure, so its deviations become everyone else's problems. Before finishing, facade and MEP trades start, the structure should be handed over with three things settled: the actual line and level of slabs, walls and columns, recorded by survey; every opening, sleeve and cast-in item the other trades need; and the engineer's confirmation that props can come out and loading restrictions are lifted. Slab levels and flatness also decide how much screed and adhesive later trades need, and whether floors finish flush.

Cast-in items are the biggest coordination point in structural work. Plates and channels for cladding and canopy fixings, sleeves for pipework and cable, roof falls and drain positions, and upstands for waterproofing all have to be in the formwork before the pour. Adding them afterwards means drilling into finished concrete, which is slower and may need the engineer's approval near reinforcement. Cladding, roof treatment and MEP works all depend on that list being complete.

Concrete, steel and canopies: what each is for

Scope points where structure meets the other packages

Structural packages are often let separately from finishing, so the boundary needs to be explicit. State in the scope or BOQ:

• The drawings and revision the price is based on, and who approves any change to reinforcement or connection details. A contractor should not change structural details on its own authority.
• The list of cast-in items, sleeves and openings, who supplies them and who checks their position before the pour.
• Mix, cover and curing requirements for each element, including exposure conditions such as coastal or below-ground concrete.
• Testing and sampling: which samples are taken, who takes them and who holds the results.
• Steel: shop drawing approval, material certificates, weld and bolt inspection, and the corrosion-protection system.
• Survey: who sets out, who checks levels, and who records the as-built position of foundations and columns.
• Temporary works: props, back-propping and scaffolding, and who decides when they can be removed.

Ground, heat and salt: what changes by region

Of all the trades, structure is the most sensitive to the ground under it and the weather around it.

• Jeddah: humid, salt-laden air raises the risk of reinforcement corrosion, so concrete quality, cover and curing carry extra weight, and structural steel needs a corrosion-protection system suited to the coast. Sound, well-cured concrete with adequate cover is the first defence.
• Riyadh and Al Kharj: hot, dry, windy conditions dry fresh concrete quickly, which can cause surface cracking, so hot-weather concreting needs planning: placing times, protection and prompt curing. Large day-night swings also move exposed steel and concrete, so joints and connections must allow for it.
• Dammam: coastal sabkha ground has low bearing capacity, a shallow water table and salts that attack buried concrete and steel, so foundation design starts with a site investigation and below-ground concrete and steel need protection chosen for that soil.
• Al Ahsa: inland desert conditions close to Riyadh, so the hot-weather points apply.

Hold points before concrete and steel are covered

For structure the checks are strictly before the fact, because neither concrete nor steel can be corrected quietly afterwards:

1. Before the pour: reinforcement fixed to the drawing, cover blocks in place, formwork clean and true, embeds and sleeves positioned, checklist signed.
2. At the pour: delivery documents match the specified mix, samples taken for testing as the specification requires, placing and compaction supervised, records kept.
3. After the pour: curing carried out and recorded, formwork struck only when the engineer allows, surfaces inspected for defects.
4. Steel before fabrication: shop drawings and material certificates approved.
5. Steel before covering: bolt tightening and welds inspected while still visible, base plates and anchor positions surveyed.
6. Canopy covering: frame checked and signed off before fabric or roofing is fixed, falls confirmed.
7. Release to other trades: as-built survey issued and the structure formally released.

Structure and finishing: one contractor or two?

When structure and finishing sit under one contractor, the handover between them is internal, but it still needs a written sign-off or the same errors travel forward unchecked. When the structure comes from another contractor, agree the tolerances and the as-built survey handover in both contracts before either starts, and say who deals with defects the finishing trades discover. Steel and canopy work often carries a fabrication lead time, so its design approvals should start early in the programme. Main Contractor vs Subcontractor: What's the Difference? sets out how these arrangements differ, and Supervision & Consultancy covers how hold points are logged.