What is a Movement Monitoring Survey?
Any building, structure or landscaped area can be subject to movement. Sometimes this will be down to forces of nature, but human intervention, such as construction works, tunnelling and large excavations could also be the cause.
A movement monitoring survey allows movement to be identified early on, before remediation costs could start to escalate, and before claims from property or landowners with resulting issues may become a potential problem. Join us as we explore the question, what is a movement monitoring survey, explaining how they work, and what you should be looking for in a movement monitoring surveyor.
How do movement monitoring surveys work?
Movement monitoring surveys work by establishing accurately coordinated targets on the face of a structure which can be measured at regular intervals over a long period of time.
The 3D coordinates (X, Y and Z) of each target are recorded at each visit to build a picture of an individual target’s movement over time, as well at the relative movements of nearby targets, to establish the mode of any movement (if any) of a structural element. This could be sinking (or rising), leaning, bowing, twisting, or simply static.
Typically, a movement monitoring scheme will be put in place before any work begins so that baseline movements of a structure can be established. Every building moves to one degree or another and it makes sense to work out the extents of this baseline movement so it can be isolated from construction-related movement as a project progresses.
Every well-founded monitoring scheme must have ‘static’ off-site references against which to measure any on-site movement. A network of local off-site ‘control’ is established, which provides the stable basis for all on-site readings.
High-accuracy total-station instruments are used to determine the control and monitoring coordinates during the monitoring scheme set-up.
Monitoring reports are generated at regular intervals, usually on a weekly basis. These show detailed comparisons, relative to baseline coordinates, reported as positive and negative movement values in three dimensions. Callidus uses a bespoke, interactive spreadsheet to enable quick viewing of all historic and current data in a variety of simple-to-read tabulated and graphical formats.
Why are movement monitoring surveys important?
Even the best-planned construction projects have unexpected issues. A diligent construction manager will understand that a movement monitoring scheme, established before any work begins on site, is the best way for them to understand the effects on theirs and their neighbours’ properties as work progresses.
Any movement can be seen at the earliest opportunity to make sure any potentially costly movements are caught and dealt with before they become a problem.
An accurate and timely movement monitoring survey is vital to reduce remediation costs and mitigate potential party wall or liability claims. They will provide the information that engineers and party wall professionals need to assess any sensible change required in methodology onsite, or inform any required remedial action.
What equipment is used for a movement monitoring survey?
Your surveyor will discuss your project with you to be able to select appropriate equipment for the movement monitoring survey based on the location and nature of the site and the goals of the survey.
Monitoring surveys utilise high-accuracy total-station instruments to measure fixed targets or prisms. A Total-Station records angles and distances very accurately, from which precise coordinates of sighted targets are calculated.
On trickier sites with awkward lines of sight, or sub-millimetre accuracy requirements, permanently in-situ electronic tilt and level monitoring cells can be installed. Not only do these provide a higher level of accuracy, but they can also record data in real time for a minute-by-minute picture.
Need to book a movement monitoring survey?
If you are serious about keeping your project on-track, the importance of engaging a movement monitoring professional cannot be underestimated. The right surveyor invests in the right equipment, software and skills to deliver the precision results you need.
At Callidus Building Surveys Ltd, we carry out all our movement monitoring surveys on an individual basis to suit the specific project, and each comes with a bespoke specification and scheme design for the best value results. What’s more, we have access to specialist, sub-millimetre equipment for situations where critical monitoring is required on a continuous basis.
Whether you’re a proactive, forward-thinking site manager who needs to demonstrate consideration and diligence to your client and neighbouring property owners, or there’s a structure, building or earthworks causing concern, you can rely on Callidus Surveys for a real-world, modern approach to precision monitoring surveys.
Our experience, site techniques and well-trained survey engineers are able to extract the very best results from the modern surveying equipment we operate.
To get started, all we need is an address, an indication of the reasons for the monitoring survey and provision of any supporting documents (party wall and/or engineer’s requirements). We can then put together a detailed specification and scheme design proposal, setting out the nature and setup of the equipment, the accuracies and tolerances, the frequency of site visits, and the short and longer-term programme.
Ready to go ahead? Please email us your survey details and we’ll get back to you with a tailored quote for a detailed structural monitoring survey using our cutting edge measured survey technology.