“Do you think that crack is anything serious?” is one question no one wants to hear the day before a project milestone.
Most buildings crack at some point during their life, that’s not news to anyone. Luckily, most cracks turn out to be static and don’t pose a threat to the structure’s integrity. Filling or re-pointing these minor fissures is usually enough.
So why monitor them in the first place?
There are two important reasons cracks need to be monitored when they’re detected:
1. Cracks can indicate serious defects that threaten a structure’s stability
Although most cracks don’t raise major concerns, some most definitely do.
Cracks can be major red flags which indicate a serious defect within the fabric of the building––one of the first signs of a more serious problem that needs to be addressed.
2. Cracks that go ignored can devalue a property regardless of the threat they pose
In addition to very real safety concerns, the mere appearance of cracked walls and other surfaces can devalue a building and affect its insurability, not to mention open the door for lawsuits in more extreme situations.
With this in mind, having the ability to assess and continuously monitor cracks when they appear is crucial.
To do this, engineers need a rigid methodology as well as high quality tools capable of highly accurate measurements.
Let’s explore crack monitoring methodology a bit more by looking at the tools that make professional monitoring possible.
Initial inspection and surveying with crack gauges
The first step to crack monitoring is an obvious one: locating the cracks.
But proper inspection is more than simply finding them. It’s also important to note any patterns that appear in the cracks, the construction materials used around them, and the age of the cracks if you can determine it.
With a rough conceptual model to work with, the next step is surveying the cracks’ present conditions using a Crack Width Gauge.
As pictured above, simply select a location on the crack where the edges relatively straight and parallel in order to get an accurate width measurement.
Record the width, length, and location of each crack and add this data to your working conceptual model where you can see each crack in relation to each other complete with its measurement information.
Using the right tools to achieve accurate monitoring measurements
After complete a crack survey, monitoring should begin as quickly as possible since the longer you can monitor a crack, the better you’ll be able to determine its cause.
There are a variety of ways to monitor cracks depending on the nature of the cracks and their position on the structure.
Tell-Tale Crack Monitors
“Tell-Tale” crack monitors are the most common kind of monitoring device used to measure cracks today and are highly valued for their easy installation and use.
Tell-Tales are capable of monitoring the movement of a crack horizontally or vertically over a flat surface and are ideal for plotting the trends and direction of movement over time. After remedial work is completed, Tell-Tale crack monitors can be re-installed to ensure the work effectively fixed the problem.
Avonguard’s Standard Tell-Tale Crack Monitors are calibrated to provide 1.0mm resolution and 0.5mm interpolation––the level of accuracy needed to make reliable measurements.
Poorer quality monitoring tools can put you at risk of potential liability when inaccurate readings lead to unneeded work.
For larger cracks, which require even greater precision, Avonguard’s Plus Tell-Tale has a larger scale allowing for monitoring up to +/-25mm in the horizontal plane. In addition, it also features spigots allowing for even finer precision crack monitoring using digital or vernier calipers.
Corner Crack Monitors
Cracks commonly appear at the corner junctions between walls and require a slightly different piece of equipment.
Although they operate essentially the same as other kinds of Tell-Tale monitors, Corner Crack Tell-Tale Monitors use a hinged gauge which fits angles between 70 and 180 degrees. When used in pairs, it’s even possible to calculate movement in all three dimensions.
Crack monitors are indispensible tools for those in charge of ensuring buildings are structurally sound and safe to inhabit.
When it comes to reliability and accuracy, it’s absolutely crucial to make sure you’re using the kinds of high quality equipment you can trust to deliver precision and reliable readings time after time.
Want to learn more about our selection of Crack Monitoring Equipment? We carry a variety of professional-level tools to fit virtually any job. Visit Berntsen’s Avongard Crack Monitor product page or request a catalog today to learn more.
Photo credit: © Superbass / CC-BY-SA-3.0 (via Wikimedia Commons)