Closing the loop: as-built capture of completed works

Most construction data flows one way: from design, down to the site. The record of what was actually built — the as-built — is too often reconstructed afterwards from marked-up drawings and memory. On road projects the problem compounds: the traditional as-built is assembled from redlines and spot measurements taken while traffic control is still in place, expensive to collect and incomplete by construction.

Closing the loop means capturing the completed works themselves. The finished surface, kerbs, drainage, barriers and signage are scanned in a single pass before demobilisation, referenced to the project datum, and compared directly against the design surface.

A handheld SLAM scanner records at walking pace, which shortens lane occupancies and shrinks the traffic-management footprint required to collect the record. Staged works can be re-scanned in minutes rather than remobilising a survey crew. The same applies indoors: a single operator captures a floor between trades, and the scan is compared against the federated model the same day — deviations surface while they are still cheap to correct.

A certified as-built point cloud in the project coordinate frame; a design-conformance report; clearance and geometry checks; and an asset inventory — kerb lines, pits, barriers, signage — as measurable data rather than paper. The contractor closes out the contract with evidence; the asset owner starts its maintenance record from the ground truth.