Movement monitoring is a specialized survey that is used to get a calculation that is very accurate that determines the rate of any building, structure, wall, or feature that may be failing over time due to movement. There are structural sensors that are used to monitor any structural movements, stresses, deformations, and strains in buildings and structures. There are a wide variety of sensors that are available so that monitoring structures can be tailor-made for any building and budget.
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There are a variety of companies that can give you this kind of service for buildings. They can do movement monitoring for any type of structure or building and can help you to decide if your building or structure needs any repair or help to prevent any damage. This can help to save you money in the long run and prevent even further damage to your structure.
You will need to do research to find just the right company that can do this service for you. You do not want someone with too little experience to be the one doing the job. You can look for online reviews or the Better Business Bureau to help with this research.
Why Monitor Movement
Movement monitoring is very important when you are constructing a new structure or rebuilding a structure that is close to other structures that might be affected by your construction work. This type of monitoring can include optical surveying and adding vibration monitors to the existing surrounding buildings. The optical surveying will check those existing structures for displacement, and the vibration monitors will continually monitor and record the peak velocities of particles.
Excavations that are beneath or next to foundations and the use of vibratory equipment can have a serious impact on the existing structures near your excavations. Because of this, you want to monitor the movement and particle velocity to ensure that you have time to prevent or fix the damage that happens because of your construction work. There should be a monitoring engineer that is monitoring all the data that the sensors provide so that the damage can be prevented before it happens.
In New York City, there are codes that say that there must be monitoring done in any underpinning activities. This monitoring, according to the New York Building Code, Section 1814.3, must also be done when you are working anywhere near a landmark. This requirement is necessary because landmarked buildings are more susceptible to damage for a variety of reasons.
Some reasons that the landmarked buildings and structures are more susceptible to damage is because many were built on rubble foundations that are mostly boulders that may or may not have any grout or mortar used. If this type of foundation was used, it has most likely deteriorated and is not as stable as it should be. This type of foundation performs poorly as other pits are dug beneath them to underpin the structures. There can be movement in these structures even if the commonly used four feet between each pin and it is recommended that there should be three feet between pins to overcome this issue.
Buildings and structures that are landmarked can also be deficient structurally because of their age. Many of these landmarked buildings were made originally with shared party walls, and many no longer have robust lateral systems to sustain them. Any construction or demolition near these structures and buildings can cause movement in these structures that can lead to complete failure of the structure.
Soil can also be a concern when you are building because of the different types of soils that exist. You will want to monitor nearby structures, especially when they are built in a sandy soil because the sand can shift tremendously during nearby construction. If you do vibration monitoring, you can prevent or greatly diminish the shifting and spilling out of sand in nearby structures.
There are three types of structural monitoring that should happen in a building’s structural monitoring program. These three types of monitoring are telltale crack gauges, vibration or movement monitoring, and optical monitoring: https://www.structuremag.org/?p=9349. These types of monitoring can help you to keep an eye on all movements so that you can be safer.
The first type of monitoring is telltale crack gauges, and this consists of putting gauges on existing cracks and other deformities. They are made of two plates, placed on each side of the crack. One of these plates is clear with crosshairs on it, the other plate has graduations. If these two plates shift during construction, the plate with the crosshairs shifts in relation to the plate that shows graduations. This shift is then easily read, and the data is reported.
Vibration or movement monitoring is the second type of monitoring that should be done. This type collects information that is similar to seismic data and blast activity. It uses a device called a tri-axial geophone to gather this type of data. You can also add a microphone to measure decibel levels at the site. This information is then sent through modems to the project manager so that they can keep on top of any movement and address the issues immediately if necessary.
The third type of monitoring is the optical monitoring which is done with a total station that is monitored several times during the week. If the structure that is being measured is called particularly vulnerable, it will be monitored more often. There are reference points that are marked and compared to benchmark points that were previously set. If these points show movement, something must be done to prevent further movement.
Conclusion
Movement monitoring is done to make sure that the construction that you are doing does not affect nearby buildings. If there is movement that is being made, you will need to alter what you are doing so that the nearby buildings remain structurally safe. If you do not do the monitoring, your construction can cause those nearby buildings to fail and possibly fall down.
