How Subcontracting Works on Motorway Projects

A motorway is never one company''s job. The main contractor divides the alignment into sections, and dozens of subcontractors produce simultaneously within each. We come from inside that system: on the İzmir-İstanbul Motorway we worked in the sections of four different main contractors.

Chainage: the address of the work

On a motorway, work is defined by kilometre, not by town. The contract says "drop-channel and apron works between KM 163+300 and 224+300" — meaning that 61-kilometre strip is yours.

Real examples from our own contracts:

Four contracts, roughly 193 kilometres of production. Delivering the same trade to different main contractors is a reference few firms carry: each has its own specification, its own supervision team and its own payment regime.

How the work is won

1. Invitation or bid: main contractors request offers from their subcontractor pools; entry to the pool is earned with completed work and references.
2. Unit-price agreement: lump sums are rare — the basis is unit price: per metre of drain, per m³ of excavation, per culvert.
3. Contract and bond: the performance bond typically runs around 6% of contract value, released at acceptance.
4. Site handover: your chainage is handed over by protocol; from then on, that strip''s output is your responsibility.

Three rules of the relationship

1. The supervision team has the last word

Every item is inspected before it proceeds: rebar checked before concrete, ground approved before fill. Unapproved work is demolished work — at your cost.

2. Measurement records are everything

Every item''s dimensions, sketches and photographs live in the measurement file; progress payments are approved against it. A subcontractor with weak records struggles to be paid for work actually done.

3. Programme discipline

Sections interlock: if your drainage is late, the pavement crews cannot start. Falling behind brings penalty clauses — and no invitation to the next tender.

Frequently asked

Does the subcontractor deal with the client authority?

The contract is with the main contractor; but the authority''s supervision inspects your work on site and effectively sets the quality bar.

Whose machines?

Usually the subcontractor''s own — our preference too: our fleet works on our contracts and is rented out when idle.

What are the payment terms?

Under monthly progress payments, cash typically arrives 30-60 days after approval. A firm that cannot self-finance two to three months of output should not take a large section.

Does this model travel abroad?

Yes — the section-and-measurement system is near-universal. We''ve applied it in Azerbaijan and are preparing for Libya: mobilisation lessons.