Tilt sensors are used for monitoring the rotation of structures. Automatic levelling of a structure can be undertaken using liquid levelling systems. Tiltmeters are used extensively for monitoring volcanoes, the response of dams to filling, the micro movements of potential landslides, the orientation and volume of hydraulic fractures, and the response of structures to various influences such as loading and foundation settlement. Tiltmeters may be purely mechanical or incorporate vibrating-wire or electrolytic sensors for electronic measurement. A sensitive instrument can detect changes of as little as one arc second.

Advantages

The main advantages of the portable tilt meter systems are the following:

  • The task of installation of tilt plates is quite simple and may be fastened or welded to the structure.
  • One tilt meter may be used to monitor many bronze tilt plates.
  • The tilt plate is made of bronze which is rugged in construction and has excellent temperature control stability.

A portable tilt meter is fir to monitor change in the inclination of a structure. Tiltmeter data can provide an accurate history of movement of a structure and early warning of potential structural damage. A tilt meter consists of a basic sensor harboured in a rugged frame with machined surfaces that enable accurate positioning on the tilt plate. The bottom surface is used with horizontally mounted tilt plates and the side surfaces are used with vertically-mounted tilt plates.

Application & Operation

While monitoring the movement of buildings, bridges and other structures, one of the basic measurements is tilt or inclination, to regulate and check any long-term leaning movement of the structures. This is indeed one of the most difficult criteria of measuring or recording the movement using proprietary instrumentation as attempt is made to monitor the movement of a static structure constructed in a way NOT to move, hence, the signals obtained can be of very low intensity or felt at a very micro level.

The tiltmeter system includes a tilt plate, a portable tiltmeter, and a readout unit. Tilt plates are available in ceramic or bronze. Both varieties are dimensionally firm and weather-resilient. Tilt plates are normally attached on to the structure in specified locations. They are characteristically fixed to the structure but may also be secured to the surface.

To get tilt readings, the operator connects the tiltmeter to the readout unit and then, the tiltmeter is fixed on the tilt plate. The operator, thereafter, records the displayed reading. Subsequently, the operator switches the tiltmeter to 180 degrees and gets a second reading. Finally, the two readings are averaged to cancel sensor offset. Changes in tilt are located by comparing the current reading to the initial reading.

We, at QSIS, use GEOKON Model 6101D MEMS Digital Tiltmeter for the measurement of inclinations. Tilt sensors are pertinent for the control and safety of the civil structures in elevation during the construction phase and operation. MEMS tilt meters monitor tilt changes in either one or two axial planes perpendicular to the surface of the base plate.

MEMS tilt meters are permanently installed to provide long term observation and are designed for manual readings.

Places of Application:

  • Bridges and piers;
  • Historical buildings;
  • Concrete dams;
  • Structural load testing;
  • Landslide monitoring;
  • Building safety along adjacent excavations;
  • Berms in open pit mines;
  • Retaining walls; and
  • Ground subsidence.

Features and benefits:

  • Accurate measure of inclination on structures (vertical and horizontal);
  • Uniaxial and biaxial versions;
  • Easy installation;
  • High performance;
  • Negligible dependence on the thermal factors;
  • Long-term stability;
  • High dynamic range;
  • Compatibility with range of web-based monitoring software;
  • Precision and durability;
  • Proven technology;
  • Low subscription cost;
  • Setup, configuration and automated download via web portal; and
  • Small dimensions and low visual impact.

    • Measurement Principle

    The Tiltmeter is constituted of two single-axis MEMS sensors (Micro-Electro-Mechanical-System). The sensitivity, reliability and sturdiness of the sensor provide assistance to the systems which monitor deformation of structures as well as rotation and tilt variations. The process of installation is hassle-free and quick, attached to the wall or ground with the aid of 3 Fixture fixings and a simple initial check with an optical level. Adjustment and refinement plates are available for special applications. Usually, systems with multiple sensors are produced, the sensors being either separate from each other or interconnected by extension bars to allow the formation of chains for monitoring subsidence and structural deformation. Instrument chains allow the monitoring of an entire profile (rather than single points) and provide greater overall accuracy of measurement.