Crack Monitoring
Cracks in buildings or structures can be harmless, but they can also indicate underlying problems such as settlement, deformation, or structural stress. With crack monitoring, the evolution of such cracks is objectively tracked over time. In this article, we explain what crack measurements are, when they are applied, and how they are interpreted.
What is crack monitoring?
Crack monitoring involves measurements where the width, displacement, or evolution of a crack in a structure is tracked. By measuring at fixed intervals, it can be determined whether a crack remains stable or continues to evolve.
The goal is not just to measure, but primarily to understand whether movement is occurring.
When is crack monitoring necessary?
Crack monitoring is often applied:
- for existing buildings with visible cracks
- for historical or protected structures
- at construction sites in the vicinity of existing buildings
- during dewatering or earthworks that may affect the surroundings
- when there is doubt about stability or settlement
In such situations, crack monitoring provides objective data instead of visual assessments.
Why is crack monitoring important?
Crack monitoring ensures:
- Early detection of problems
- Objective monitoring instead of subjective assessment
- Informed decisions regarding repair or further monitoring
- Reduction of disputes between involved parties
Without measurements, it is often impossible to say with certainty whether a crack is active or not.
How is crack monitoring performed?
There are various methods for monitoring cracks, depending on the situation:
- Crack gauges or monitoring plates
These are placed on or in the crack and allow for the registration of small displacements. - Prisms and surveying measurements
For larger structures, the global movement of a construction can be monitored by a land surveyor. - Sensors
In some cases, continuous measurements with automatic sensors are chosen.
The chosen method depends on the required accuracy and the duration of the monitoring.
Crack measurements versus monitoring
Crack measurements are often a first step. When the measurements show that there is actual movement, one can proceed to long-term or automatic monitoring. This creates a clear picture of the structure’s behavior over a longer period.
What do crack measurements tell us and what do they not?
Crack measurements show if and how much a crack is moving. However, they do not automatically indicate the cause of the problem. Interpretation is always done in conjunction with the context of the building, the soil, and any works in the vicinity.