The process also involves monitoring specific locations at regular intervals. Inspections can be carried out on a daily, weekly, monthly, fortnightly, or yearly basis, but it will mostly depend on the nature of the job. In most situations, monitoring reports will be taken at these intervals and reported on request to the client.
Types of Survey Schemes
There are actually four commonly used survey monitoring schemes.
- Laser Scanning: A given structure is scanned using a laser which is supposed to capture a variety of points that can be compared to each other over the passage of time.
- Fixed Position Monitoring: It involves the identification of fixed points of a certain structure and observing the movement over a specific time period.
- Tilt Sensor Monitoring: This survey involves checks which will result in learning at what degree a wall tilts to a particular direction.
- Crack Monitoring: This type of monitoring is done to determine if a crack on a building is opening or closing over time.
Why are Monitoring Surveys Useful?
In most cases, if a structural engineer determines it, a monitoring survey is carried out to determine if a structure is at risk of moving. It would also be a good idea to carry one out if some heavy construction work is being done close to a building which may involve basement excavation, any kind of demolition, or piling.
A monitoring survey will help determine any types of further movements in the case of a structural collapse. Checking for movements is much less expensive than having to do any type of reconstruction, making it wise to do these types of surveys from time to time. Not to mention that these types of surveys could prevent potential loss of lives or injuries from happening due to a structure moving or tilting too far.
When is a Monitoring Survey Necessary?
Monitoring surveys are a necessary action that needs to be done in any type of a situation that requires measurements of potential movements. Surveys are effective not only for man-made structures but also for some natural ones. Any structure that may experience some sort of shifting may benefit from a survey.
What Does a Monitoring Survey Involve?
A monitoring survey involves capturing any potential horizontal or vertical changes in position, no matter how big or small they prove to be. These changes can happen over a long-term monitoring project or could occur in real-time. During a real-time survey, surveyors will take multiple measurements during a single day. However, in the case of long-term monitoring surveys, measurements may be taken as far apart as once a year.
Real-time monitoring surveys are usually used during excavations in which case some current projects may cause structural disruptions if they would continue. Long-term surveys may be done less frequently but help in taking the necessary actions that are needed if some shifting happens.
The data compiled from these types of surveys are used for better planning and design in the future as well as providing baseline numbers that future surveys could be compared with.
What Does a Monitoring Survey Achieve?
Monitoring surveys are useful in making long-term decisions as well as making sure for a person not to be liable for any shifting or disruptions. It can work as a requirement for insurance and also helps to determine if the project is disrupting any nearby structures.
As far as long-term implications go, it helps to identify concerns no matter if they are immediate or latent and allows for proper action to be taken. Monitoring surveys are particularly helpful when measuring erosion's.
What to do After a Survey?
Once a monitoring survey is done, the surveyor will present and provide the given data along with recommendations on potential actions that need to be taken. These official reports can be used for both planning and maintenance.
What Projects Require Monitoring Surveys?
A monitoring survey will usually be taken upon the advice of a professional like a Party Wall Surveyor or a Structural Engineer. If a certain building or structure is at risk of possible movement then a monitoring survey will need to be commissioned.
Monitoring surveys are usually commissioned when heavy construction work is being done next to an existing building. It can also be commissioned as a check for insurance claims. But the usual situations involve:
- Piling works
- Basement excavation
How Often Does Property Need to be Monitored?
Generally speaking, it is important to have at least one survey before undertaking any work. It ensures you have a base reading against which any further readings can be compared to. If a survey is conducted after some work has been already done, then one might miss any initial movements in the structure.
However, when it comes to some major operations that involve underpinning, digging, concrete pours, etc., then weekly surveys are recommended until everything is complete. After heavy work and construction are complete, the surveys can be changed to a monthly schedule before the internal work begins. Once the internal fitting has started, movements are limited so surveys can cease entirely.
It is best to determine the frequency of surveys with the project manager as some projects may require more frequent surveys compared to others.