Resources - Concrete Yellow

Inspection case study

Avoiding Catastrophic Collapse: Lessons Learned from a Ground Beam Set Out Error

Ground beams are critical to the overall stability of a building. The ground beams serve as the concrete foundation between the primary steel and provide support for the secondary steel. 




Due to issue being caught early after only 2 of 6 ground beams had been installed


26 DAYS 

Rework, repositioning and correction if the error had been spotted using traditional checking



Mission Critical



8,000 m2

Errors during the setting-out of structural ground beams, can result in a significant amount of rework and impact the timeline of a construction project, and potentially impact the structural foundation of a building.

In this case study, XYZ Reality’s Engineering Grade AR™ headset, the Atom™ and field engineer revealed the placement of two concrete beams was off by 60 millimeters (2.3 inches). If not corrected, this discrepancy would have had significant consequences on the structure integrity of the building and the overall timeline of the project.

Ground beam setting out error - construction AR inspection
Size of discrepancy in setting out - construction AR inspection
Ground beam setting correct - construction AR inspection
Correcting the error with construction AR - construction AR inspection

During a routine inspection of the structural ground beams on a pharmaceutical project, an error was identified in the placement of two concrete beams.

The beams were identified to be off by 60 millimeters (2.3 inches).The XYZ Field Application Engineer (FAE) identified that the rebar and formwork were in the incorrect position and would have continued that line for half of the ground beams. 

By identifying this error at the point of rebar installation, instead of at a later stage, the issue was rectified before the concrete pour, saving valuable time and material costs. In this particular pharmaceutical project, the margin for error was tight, as the outside of the beams are crucial for positioning the external façade of the building. The secondary steel sits on top of the beams and a deviation of 60 millimeters is far too much, with an allowable tolerance of only 10 millimeters (0.39 inches).

The incorrect placement of two ground beams would have caused logistical issues with the schedule and underground pipe placement had it not been for XYZ’s early intervention. Identifying the error early on prevented it from becoming a bigger issue throughout the entire building.

To correct the issue, extra reinforcing had to be added, then the concrete was poured on the outside to fill the gap.


Finding this issue early meant that the construction team avoided having to do this work twice to fix the mistake. Therefore, money saved would be roughly £15,000 and time saved would be 25+ days.

Design misinterpretation

The alignment of the ground beams is different around the building. The project engineer assumed that the position and offsets would be the same across the project. However, when the engineer put the Atom headset on, he realized that he had made a mistake in the offset. Had this human-error have continued, without XYZ’s interference, half of the ground beams would have been radically offset, which would have led to serious rework, or redesign for this particular area of works.

The knock-on effect

If the error had impacted the entire length of the building it would have been a major headache for the project, likely leading to delays and schedule overruns. Fortunately, with XYZ onsite, the issue was caught early, with only two beams being incorrect. The takeaway from this inspection is that early detection of errors saves time and resources in the long run.

Why is it important to build it right, first time?

The importance of accuracy throughout the construction life cycle from foundations to MEP cannot be overstated. In this case, the XYZ FAE was able to identify the issue and prevent a much larger problem from happening. The error in the placement of two beams was significant, but the impact was limited because of the swift action taken. This case study highlights the importance of proper coordination and the consequences of not addressing issues in a timely manner.

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