instrumentation & monitoring

Instrumentation > Instruments > Joints/Crackmeters > Mechanical Triaxial Jointmeter

Mechanical Triaxial Jointmeter

The Mechanical Triaxial Jointmeter is designed to measure movement in three axes across any joint, be it a construction joint in concrete or a tension crack in rock.  

The Mechanical Triaxial Jointmeter is designed to monitor three way displacement (X, Y and Z) across joints or cracks between adjoining concrete and rock structures. 

The Jointmeter comprises two elements; a zinc coated measurement arm and a Stainless Steel reference head, both attached to reinforcing bar embedment anchor stems. 

The measurement arm incorporates three orthogonal locating bushes, designed to receive a mechanical or electronic micrometer. 

The Stainless Steel reference head is a cubic anvil, with precision machined reference faces, providing a surface against which the triaxial displacement measurements are made.

Manual measurement with a mechanical gauge is a more preferred option when fewer readings are required.

Product Features 
Reads in X, Y and Z axes
Accurate and precise
Proven in long-term monitoring
Simple in principle and operation
Product Benefits 
Three way independent movement monitoring in one easy installation
Low and easy maintenance
Long working life, long-term stability and reliability
Operation

The arm anchor stems are embedded at either side of the joint, crack or fissure to be monitored, either in wet concrete at a construction joint, or grouted firmly into drilled holes in a pre-existing mass or structure, using cementatious or chemical grouts.

A temporary, removable jig maintains the two halves of the jointmeter in correct alignment at its mid-range, until the embedment medium has gained sufficient strength to be able to fully support the jointmeter.

Readings are acquired by recording the current distance from the measurement bushes to the reference anvil in X, Y and Z planes. The current readings are then subtracted from an initial base reading to give relative movement of the joint or crack.

Applications

The Mechanical Triaxial Jointmeter is used for the measurement of X, Y and Z dimensional relative movement between two abutted structures or masses.

Typical applications include:
Concrete dam construction joints
Tunnel and shaft lining segments
Bridge construction
Masonry structures
Structural and superficial cracks