Structural Movement Monitoring
The monitoring of movement within a structure requires repeat measurements over an interval of time. The measurements can be taken using :
- A Total Station
- Laser Scanner
- Other Device
The choice of measuring device will depend on :
- the expected degree of movement
- the required accuracy
- The distance from the structure being monitored
- The period of time the structure is to m be monitored.
Accurate monitoring is dependant upon there being fixed control points located in areas where movement is unlikely to occur over the monitoring period of time. This will allow the initial and subsequent measurements to be related to constant and fixed reference points.
Tunnel Movement Monitoring
The monitoring of movement within a tunnel requires repeat scans over an interval of time. Scans are initially taken throughout the tunnel or in the area where movement is suspected. Subsequent scans at say 6 months later are then compared against the original data to determine whether there has been any movement.
We have proved that 3D laser scanning technology can be applied to monitoring tunnel movement by comparing cross sections over a specific time period. This method requires setting up a control network during the initial survey to ensure that all subsequent cross sections are extracted in precisely the same location. The cross sections are then overlaid over the previous sections and inspected either visually (in AutoCAD or Microstation) or using co-ordinate data.
We have developed a proven methodology to ensure that the comparison is carried out in exactly the same location no matter how many times the tunnel is scanned. We can demonstrate this capability and if you would like further information please contact Keith McCrory.
Since 2003 we have undertaken dozens of such surveys and have developed additional deliverables to assist in the asset management of these structures.
Bridge Movement Monitoring
The monitoring of movement of a bridge is usually monitored using a Total Station to measure the deflection of the road or rail surface however Laser Scanning can also be utilised for specific applications.