ShapeArrays are manufactured by Measurand Inc. of New Brunswick, Canada and are used for measuring ground and structural deformations.
A ShapeArray (SAA) is an array of rigid segments separated by joints that move in any direction but do not twist. MEMS gravity sensors measure tilt in two directions. Processors transform the position (e.g. X, Y & Z) of each joint to produce shape and change of shape.
Each ShapeArray comes on a drum and is installed inside and access tube that is grouted into a borehole or a void former. Installation and removal of ShapeArrays is extremely simple because there is no joining of individual sensors to be done in the field and the single wire output from a ShapeArray means there is very little wiring to be done to complete the installation process.
ShapeArrays can be used in vertical, horizontal and circular orientations. For inclined and near vertical orientations (< 60 degrees to the vertical) ShapeArrays record X, Y and Z coordinates of each joint and for horizontal arrays, settlement (e.g. X-Z, where Z represents distance along the array) can be recorded. Convergence can be measured in tunnels and sewers.
Displacements can be stored on dataloggers or read directly on computers and mobile phones. SAAs come in lengths of up to 150m. Long-term tests have shown that 32m long ShapeArrays are accurate to ±1.5mm and precise to ±0.5mm.
ShapeArray is a London Underground Registered Product (ID 2721: Asset monitoring of tunnels, track beds, walls, bridges, other structures and earthworks) and has ATEX certification for use in potentially explosive environments (e.g. sewers).
SAAV
SAAV is the most advanced ShapeArray model to date. Inspired by direct feedback from clients, SAAV has been developed to be installed directly into any casing with an internal diameter between 27mm and 100mm. This means that it can be installed quicker than any other in-place inclinometer, including its soon to be discontinued older sibling SAAF.
SAAV is ideal for retrofitting into existing conventional inclinometer casings. Its unique off-the-reel cyclical installation system (patent-pending) inserts the ShapeArray in a zigzag pattern inside the casing and it is then held in place by an innovative top-cap. Software tracks the medial axis of the casing to produce accurate and precise displacements.
For situations where the SAAV is not required to reach all the way to the bottom of the casing, silent segments can be inserted at the bottom of an SAAV. Silent segments have no sensors inside and are connected at the far, non-cable end of the SAAV to increase the total length of the array. This innovation is useful when SAAV is installed into existing casings where the shear zones are known to be well above the bottom of the hole or to accommodate for casing depths that are not identifiable at the time of order.
SAAV contains the latest MEMS sensors that significantly reduce power consumption and improve resolution. Each segment measures tilt in two orthogonal directions, which is an important feature that will produce more accurate results than in-place inclinometers that make uniaxial measurements.
SAAV can be up to 150m long and is available with segment lengths of 250mm and 500mm.
SAAV can also be configured to measure convergence in tunnels and horizontally for monitoring settlement. In horizontal orientations though SAAX is more economic.
ShapeArray will produce more reliable and accurate measurements than in-place inclinometers with longer gauge lengths.
SAAV Extend
SAAV Extend is a ShapeArray that can be increased or decreased in size according to the requirements of the project. Each SAAV Extend includes a top assembly that connects to a base assembly creating a normal looking ShapeArray with the same accuracy and reliability of an SAAV. However if the instrument needs to be extended or moved to a different project an SAAV_Lift section can be inserted between the top and base assemblies.
SAAV Extend is the most versatile ShapeArray yet.
SAAX
SAAX is purpose built with 1000mm long segments and is for use in horizontal orientations such as monitoring settlements beneath earth structures, inside tunnels and along pipelines.
SAAX is available in lengths up to 200m.
SAAX is perfect for monitoring settlement beneath embankments and it defines the settlement trough very nicely. Recently we combined SAAX for monitoring the settlement across an embankment with an RST in-line extensometer for monitoring the settlement profile with depth at the centre of the embankment. Both instruments showed perfect agreement at the surface. Contact us if you would like to know more about how to do this.
SAAScan
Designed to be used, moved, and re-used as quickly as possible, SAAScan is ideal for applications where borehole shape must be measured repeatedly (e.g. jet grouting and borehole drilling). SAAScan’s robust and durable construction combines twist-resistant joints and thick-walled stainless steel segments. SAAScan’s segment length is 500mm and it can be manufactured to a maximum length up to 100 m.
