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Target Monitoring / Movement Monitoring
Here at Moniteye, we use the most accurate total station products to provide target monitoring services on a nationwide basis. This technique is suited to a wide range of scenarios and provides invaluable information to Engineers, Party Wall Surveyors, Architects, and Construction Teams on the behaviours of structures.
This structural monitoring technique provides accurate movement data during each phase of construction projects giving peace of mind to all those involved in the build and those directly affected by it.
Moniteye is able to provide a quick start service helping to avoid any costly on-site hold ups, and we have a track record of consistently delivering accurate results to our clients in a timely manner.
What is Target Monitoring / Movement Monitoring?
Target monitoring, sometimes referred to as movement monitoring or total station monitoring, is the manual or automated measurement of a structure’s absolute movement. The use of targets allows for movement to be measured in the three axis, both horizontal and vertical, or X, Y and Z. By working from a number of control points that are not experiencing movement, the relative movement of any other point can be calculated using the velocity and time taken to travel by light between the two points. Using this method can produce result with an incredible accuracy of +/-1mm, perfect for critical measurements where precision is an absolute must.
Who Needs Target Monitoring / Movement Monitoring?
There are any number of natural reasons that a structure may move during its lifetime. Typically, these can be broken down into three categories: ‘subsidence’, ‘settlement’ and ‘heave’. There are, of course, manmade reasons for structures to move which also must be considered, including mining and ground/demolition/construction works.
Subsidence Monitoring
Subsidence occurs when the ground beneath a structure becomes unstable and the building begins to sink downwards. This usually happens when the ground beneath the structure shrinks due to prolonged drying spells, or due to trees and/or other flora drawing the moisture out of the area.
A common first sign of subsidence is cracking in the internal plasterwork or external masonry of a building, often occurring quickly following an extended period of dry weather.
Target monitoring can provide structural engineers and insurers the data they need to assess the impact of subsidence on a structure, by taking regular measurements of how the building is moving in relation to a non-moving, fixed asset.
Settlement Monitoring
Settlement differs from subsidence as it is a result of the weight of the structure on the soil below, causing the building to move downwards from its original position. There are several types of settlement, including uniform settlement, differential settlement, and tipping settlement, with uniform settlement usually causing the least structural impact as the whole building moves downward evenly.
Settlement usually occurs within the first 12 months following the construction of a building, but the effects can continue to develop for a
significant amount of time beyond this. These can include hairline cracks in plasterwork, or doors and windows sticking, and potential plumbing issues.
Whilst tilt and crack monitoring will be able to measure the turning and cracking caused by settlement respectively, neither method can measure the vertical movement of a structure such as that caused by uniform settlement. In order to monitor settlement correctly, target monitoring / traditional monitoring must be employed to capture the vertical movement of a structure.
Heave Monitoring
Building movement heave, or ground heave, is when the ground beneath a structure moves upwards. This is usually associated with clay soils which, when wet, swell and expand thereby creating movement. The effect of heave is almost the opposite of subsidence.
Common signs of ground heave cracks in brickwork and internal plasterwork, as well as sticking doors and windows. Lifting paths and patios may also be seen around the building as the ground shifts.
There are multiple methods of monitoring for heave, including level monitoring, tilt beam monitoring and, of course target monitoring / traditional monitoring. As with Subsidence Monitoring and Settlement Monitoring, tilt and crack monitoring will be able to measure the turning and cracking caused by heave respectively, however, neither method can measure the vertical movement of a structure. In order to monitor all axis of movement in a structure suffering ground heave, target monitoring / traditional monitoring must be employed.
Structural Monitoring for
Construction Sites & Demolition Sites
Whether you are demolishing a residential property, piling for a new high rise or digging for a basement extension, there is the potential for movement to impact on surrounding structures. It is critical to all projects of this nature to ensure that the ongoing works do not compromise the structural integrity of the buildings around them. Any such damage caused could mean delays to projects, costly remediation works and the potential for serious health and safety issues.
With regular target monitoring / traditional monitoring visits to measure the movement of at-risk structures, you can ensure that the works that are taking place are not affecting the integrity of the structures around you. Whether these visits are once a week or once a month, we can accommodate you, providing reliable data in a timely manner, alerting you to any threshold breaches that may require your attention.
