Acuo Structural Insights
Case Studies

Precision in Practice.
Real Projects. Real Data.

From complex concrete scanning on live infrastructure to full digital twin surveys of heritage buildings, our work speaks for itself.

Zero-Impact Block and Beam Identification in a Luxury Central London Apartment — ACUO structural survey case study
3D GPR & AR VisualisationCentral London

Zero-Impact Block and Beam Identification in a Luxury Central London Apartment

A structural engineer needed to confirm the floor construction in a high-end apartment in Central London ahead of refurbishment works. The room had a finished luxury parquet floor, the brief allowed zero marking tolerance, and the work had to be carried out with complete discretion.

Scope

3D ground penetrating radar survey scanned directly through the finished parquet floor. Augmented reality visualisation overlaid scan results onto the live view of the room in real time — no surface markings, no breakout, no disruption to occupants.

Outcome

Confirmed block and beam floor system with beams at 600mm centres and a clear span of 5.2m. The engineer received reliable structural data with zero damage, zero marks and zero disruption, and was able to move forward with confidence.

0
Marks made
600mm
Beam centres
5.2m
Clear span
Non-Destructive Investigation of Railway Bridge Columns – Delivered in One Day — ACUO structural survey case study
GPR & Cover Meter SurveyRailway Infrastructure

Non-Destructive Investigation of Railway Bridge Columns – Delivered in One Day

The principal contractor needed to establish the internal reinforcement of concrete columns supporting a railway bridge before strengthening works could proceed. No reliable record drawings were available, a single day on site was all that was available, and breaking out the columns was not an option.

Scope

3D GPR and electromagnetic cover meter survey of 5m-high, 1.5m-diameter concrete columns. Vertical bar locations, ligature positions and cover depths measured at multiple heights. Scan data processed and verified on site before leaving.

Outcome

Full reinforcement picture delivered in one day without damage to the structure: 16 vertical bars at approximately 38mm diameter, cover 60–75mm, ligatures at 150mm centres with 55mm cover. One remaining unknown clearly identified with a targeted, low-impact route to close it out.

1 day
On site
16 bars
Vertical reinforcement
0
Break-outs required
Post-Tension Slab Mapping — Mixed-Use Development — ACUO structural survey case study
3D Concrete ScanningLondon, SE1

Post-Tension Slab Mapping — Mixed-Use Development

Pre-demolition GPR survey of a 12-storey post-tensioned concrete frame in central London. With no reliable as-built drawings available, the structural engineer required a full picture of PT cable and rebar positions across every floor before structural alteration works could be safely programmed.

Scope

Full-building GPR survey across 8,400m² of post-tensioned slabs over 12 floors. Scanning carried out in a live building with occupied tenancies on lower floors, requiring careful access coordination. 3D sub-surface models delivered within 48 hours of survey completion, with PT cable positions plotted to ±25mm accuracy.

Outcome

Three previously uncharted PT cable deviations identified — each within 150mm of a proposed core location. Zero structural incidents during subsequent demolition and alteration works. The survey data was used directly to revise the core programme, avoiding three potential cable strikes and the associated programme delays and liability.

8,400m²
Scanned
48hrs
Report turnaround
3
Cable strikes avoided
Corrosion Assessment — Multi-Storey Car Park — ACUO structural survey case study
NDT Corrosion SurveySurrey

Corrosion Assessment — Multi-Storey Car Park

Comprehensive NDT investigation of a 1970s multi-storey car park to assess chloride-induced corrosion risk across all decks and inform a £2.4m refurbishment programme. The client needed objective condition data to challenge an overly conservative repair specification and avoid unnecessary concrete removal.

Scope

Half-cell potential survey across 4,200m² of deck area, carbonation depth testing at 48 locations, and chloride profiling at three depths (20mm, 40mm, 60mm) at 24 sample points per deck. Defect mapping and condition grading delivered for all 6 decks, with corrosion probability zones plotted to 1m² resolution.

Outcome

Half-cell readings confirmed active corrosion in 18% of the surveyed deck area — significantly less than the 53% assumed in the original repair specification. Chloride levels exceeded the 0.4% threshold at 40mm depth on the top two decks only. Survey data directly reduced the repair area by an estimated 35%, cutting unnecessary concrete removal and saving significant programme cost against the original budget.

4,200m²
Deck area surveyed
35%
Repair area reduction
£2.4m
Programme value
Tunnelling Vibration Monitoring — Victorian Railway Viaduct — ACUO structural survey case study
Movement MonitoringKent

Tunnelling Vibration Monitoring — Victorian Railway Viaduct

Real-time wireless monitoring of a Victorian brick railway viaduct during adjacent tunnelling works for a new utility corridor. The asset owner required continuous structural monitoring with automated alerts throughout the tunnelling programme to satisfy Network Rail's asset protection requirements.

Scope

32-sensor wireless monitoring network deployed across 6 spans of the viaduct, measuring vibration velocity, tilt, and crack width at critical locations. Sensors calibrated to Network Rail PPV thresholds. Continuous data streaming to a live dashboard accessible to the client's project team, with automated SMS and email alerts set at 80% and 100% of threshold values. Weekly condition reports issued throughout the 14-week programme.

Outcome

No threshold exceedances recorded across the full 14-week monitoring period. Peak PPV recorded was 3.2mm/s against a 12mm/s threshold — providing the asset owner and contractor with documented evidence of structural integrity throughout works. Client maintained full programme confidence with zero unplanned stoppages or Network Rail interventions.

32
Sensors deployed
14 weeks
Monitoring period
3.2mm/s
Peak PPV recorded
As-Built Digital Twin — Grade II Listed Office Building — ACUO structural survey case study
Digital Twin & Lidar SurveyLondon, EC2

As-Built Digital Twin — Grade II Listed Office Building

Full Matterport and lidar survey of a Grade II listed office building in the City of London, creating a precise as-built digital twin for a major Cat A refurbishment. No current as-built drawings existed, and the design team needed accurate dimensional data across all floors before detailed design could begin.

Scope

Complete internal and external lidar capture across 7 floors and roof, totalling 3,850m² of floor area. Point cloud data registered to ±5mm accuracy and exported as a fully navigable Matterport model with embedded measurement tools and annotation layers. Floor-to-ceiling heights, column positions, structural openings, and M&E service routes all captured and tagged. Model delivered within 5 working days of survey.

Outcome

Digital twin used by the architect, structural engineer, and M&E consultant throughout the design process. Dimensional discrepancies of up to 180mm identified between the existing floor plates and the client's legacy drawings — data that would have caused significant abortive design work had it not been captured before detailed design. RFI volume reduced by over 40% compared to the client's previous refurbishment project on a comparable building.

3,850m²
Floor area captured
±5mm
Point cloud accuracy
40%
Fewer RFIs
Basement Plant Room GPR Scanning, London — ACUO structural survey case study
3D GPR Concrete ScanningLondon

Basement Plant Room GPR Scanning, London

A contractor needed to know what was in the floor of two basement plant rooms before starting new works. One room held the electrical plant. The other held the fire water tanks, pumps and generator.

Scope

We scanned both rooms with a Proceq GP8000 GPR, combining 2D line scans and 1 m × 1 m 3D grids to a depth of about 900 mm.

Outcome

The engineer received an engineering report with annotated 3D scans, section drawings and a clear drilling status for every zone, along with a defined scope to close the remaining gaps.

900 mm
Scan depth
2 rooms
Scanned
3D grids
1 m × 1 m
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