Problem

Mistakes during groundworks are usually buried with the underground services. However, as the testing & commissioning phase begins, these same mistakes always find a way back to the surface creating major disruptions to the site, including:

• Bringing back heavy equipment
• Creating large excavations and exclusion zones

Scope of Works

The Main Contractor decided to implement HoloSite inspections at the earliest stages of the project - during groundworks and underground service installations. This ensured that the associated buried utilities and services would be an accurate reflection of the model, preventing unwanted surprises during any future groundworks. For this specific scope of works, the Main Contractor used HoloSite to identify and correct any issues during excavation and installation, specifically:

• Inspection of service locations prior to excavation works commencing
• Inspection of services during installation (correct depths, slopes and locations)

Results

Using HoloSite, the Main Contractor managed to catch several errors early during installation, including:

• Drainage pipe directly under the data centre misaligned by 150mm
• Manhole location incorrectly set out

After correcting these errors, the Main Contractor and their trade contractor updated their QA/QC process to include a pre-installation setting-out and a mid-installation walk-down using HoloSite. This proactive approach during the typically rushed early works stage would enable early detection of mistakes mitigating costs associated with rework, redesign and delays.