Tilt monitoring is primarily used for measuring the vertical and horizontal rotation of structures on projects involving deep excavation, heavy demolition or blasting near structures of concern.
Construction operations frequently have sensitive thresholds for movement on and around the site. Tilt meters are a monitoring solution in such circumstances – and GeoSonics/Vibra-Tech tilt meters have the additional advantage of being able to operate continuously as part of our Re:mote Monitoring system. Incorporating dual axis motion sensors with the unit allows the evaluation of structure motion, with results delivered in person or via a customized client website. The sensitivity of our equipment enables precise motion detection. Multiple instruments can monitor all aspects of structure motion. By updating results at regular, predetermined intervals, there is no chance of movement occurring without notification.
Our tilt meter system is used to record variance in the inclination of a structure. It is particularly useful in early or historic construction. Variance in inclination is fairly common in such structures, and it is important to monitor even slight change. Buildings with non-square or out-of-level walls are not necessarily structurally unsound, but they do warrant monitoring since they may have a greater potential for damage. We have deployed systems with scaling to record +/- 1 degree, thus providing a resolution of 0.0006 degrees.
Standard systems typically use bi-axial tilt meters with scaling to record +/- 10 degrees with a resolution of 0.005 degrees of tilt. Data is typically collected at one-minute intervals and recorded to a histogram. Web-based presentation and reports can also be generated for degrees of tilt or for inches of deviation, depending on requirements.
GeoSonics/Vibra-Tech tilt meters are inertially referenced to the most stable baseline of all, the vertical gravity vector. They provide a precise, dependable record of all angular movements with respect to gravity. They can minimize the time and expense spent continuously surveying benchmarks and other data. Simply install the tilt meters and begin your measurements. Rotations induced by settlement or loading can directly convert to displacements, moduli, movements, and shears using standard engineering formulae.
Tilt meters can also be used for construction safety. Excessive structural or foundation movement during construction or other vibration-inducing events is a precursor to structural failure. Tilt-meters connected to a warning system can trigger alarms when allowable limits are exceeded, permitting corrective action before damage occurs. Continuously recorded data provides a permanent record of events.
Dynamic Crack Monitoring
The crack gauge is a valuable tool for observing the movement of a cosmetic or structural crack during vibration causing events.
The GeoSonics/Vibra-Tech crack gauge systems yield both comprehensive dynamic and environmental information on crack displacement. Dynamic data (recorded during a vibratory event) is essential for determining a crack’s activity during excitation. Our crack gauge system shows if there is any correlation between crack movement and other vibration producing activities.
Crack monitors allow us to measure changes in crack width due to normal temperature variations and compare it to crack movement due to construction activity or potential settlement. Often these results are used in conjunction with vibration data to address claims due to blasting or construction activity.
If you need to measure the deformation of a particular element or material due to some applied load during construction or blasting, strain gages can provide a solution.
For measuring lateral movement of engineered structures and slopes, Re:mote in-place inclinometers systems are a useful tool for such monitoring. Horizontal and vertical inclinometers provide profiles of differential and accumulated displacement during construction and blasting activities.
If ground settlement or heave is of concern, single or multiple point borehole extensometers can be used to measure this movement. Extensometers can also be used for detecting movement of underground structures such as tunnels and utilities.
Monitoring water elevations in boreholes, lakes and streams is often necessary during construction projects to monitor dewatering efforts or evaluate construction effects.