In our joint webinar with Measurand, Todd Roberts P.G. and Jeff Barrett discussed the benefits of ShapeArray deformation sensors paired with sensemetrics’ cloud-based data monitoring platform in creating a streamlined wall deformation monitoring solution for Yeager Airport.

We were very pleased with the attendee engagement during the live session and have compiled responses to many of the questions that our presenters did not have time to answer during the live Q&A session. 

We appreciate everyone’s interest and participation, and remain available to answer additional questions. Feel free to submit them using the form at the bottom of this page. Webinar replay is available on-demand for those who were unable to attend the live presentation.

Q. Do you need to buy the Measurand datalogger and sensemetrics Thread, or just the sensemetrics Thread?

Jeff Barrett | President, Measurand

A. You only need to purchase the Thread. There is no need for any other loggers or interfaces when combining Measurand ShapeArrays with sensemetrics Threads.  

Q. Can sensemetrics receive factual data of various types and manufactures at the same site?

Nate McGee | Technical Director, sensemetrics

A. Yes, sensemetrics connectivity devices are designed to support wired and wireless connections for an extensive range of sensor types, makes, and models. Once connected, each sensor is easily configured using the sensemetrics mobile app, or web browser application.

Q. What are the principal differences between conventional in place inclinometers and ShapeArrays?

Jeff Barrett

A. There are 5 main differences:

1. ShapeArrays offer a higher spatial resolution with a sensor position at 500 mm increments for vertical installations or 1000 mm for horizontal installations. This provides a dedicated sensor at every 0.5 m elevation with a per segment resolution of 0.5 mm. Regarding price, we have found that an IPI with a 2 m gauge length (spacing) is a similar cost to a ShapeArray with 500 mm segments, not including labour hours associated with implementing the systems. 

2. The accuracy specification relative to the baseline reading for a 32 m ShapeArray is +/- 1.5 mm. This is an installed, field-tested value that users can expect with each model ShapeArray, not a specification that was derived from testing in a controlled lab environment.

3. ShapeArrays have proven their exceptional deformation tolerances on a number of projects, specifically a roadway failure in Minnesota USA a number of years ago where vertically installed ShapeArrays withstood a complete failure with a deformation magnitude totalling 3 m. 

4. For vertical installations, ShapeArrays do not use the casing grooves or centralizers, so spiral corrections are unnecessary, and the client has the option of substituting standard inclinometer casing with a lower cost PVC conduit (or similar material). 

5. Implementing ShapeArray is quick and low cost. Each instrument arrives pre-calibrated and ready for installation. Measurand also has a dedicated Support Team available for post-installation services that is free of charge.

Q. Does sensemetrics use mesh networking?

Todd Roberts, P.G. | Director of Infrastructure, sensemetrics

A. The sensemetics Thread uses an adaptive and resilient self-forming radio mesh network. Using automatic role detection, it can configure itself as a gateway, repeater, or endpoint. The sensemetrics connectivity cloud also supports secure connections to a wide range of 3rd-party gateway devices that administer mesh or star network topologies. Review the Thread data sheet for more information.

Q. Is the SAA inclinometer casing anchored to the bedrock or more stable foundation?

Shane Spinney | Support Specialist, Measurand

A. Much like any deformation monitoring product, measurements with a ShapeArray require a stable reference point that is assumed to be unmoving. For this reason we would want the casing to be anchored into a stable foundation.

Q. Were there any radio frequency limitations that caused communication issues for the Thread?

Todd Roberts, P.G.

A. The sensemetrics Thread uses a frequency hopping spread spectrum (FHSS) radio that is very effective at avoiding interference. It operates in the ISM band, meaning it does not require a user to obtain a permit or license to operate it. On this project, we did not experience any issues or limitations related to wireless data transfer, even operating adjacent to an active airport facility with radar, etc.

Q. Is the temperature correction range based on ambient temperature or instrument temperature? If instrument temperature, what might you expect to see if the instrument reaches a temperature higher than 60C?

Shane Spinney

A. The temperature is measured by a sensor built into the instrument’s electronics within the segments. We only calibrate based on temperatures up to 60 C; however, the calibration algorithm is based on a polynomial equation which should remain quite accurate beyond our specification limits.

Q. Is there a limitation to how many sensors can be connected to a Thread? How many SAA strings can one Thread have?

Todd Roberts, P.G.

A. Up to two (2) ShapeArrays can plug directly into the Thread, with no additional device requirements. In addition, projects can use various wired and wireless multiplexing devices to automate hundreds of sensors, if needed.

Q. Can the SAAVs lengths now be adjusted in the field?

Shane Spinney

A. The sensorized length of a ShapeArray cannot be adjusted in the field currently. We can accommodate longer borehole lengths with un-sensorized silent segments at the bottom and un-sensorized extension rods at the top. These un-sensorized portions allow you to monitor a specific targeted zone within the borehole. Learn more: Attaching Silent Segments to SAAV

Q. Were there any cases where the alert system was activated preventing an incident?

Todd Roberts, P.G.

A. Not specifically for this project but there have been instances on other projects where the sensemetrics platform proactively alerted the project team to changes in site conditions which enabled the team take action before more significant events occurred.

Q. Are any wheels or special attachments required to install a ShapeArray into inclinometer casing?

 Jeff Barrett

A. No, The ShapeArray can be installed directly into the casing in any orientation. ShapeArrays are not reliant on the grooves for orienting data. Data is oriented relative to an X-mark on the instrument which determines the positive X-axis direction and an offset to this X-mark can be entered into the software to re-orient the data axes.

Learn more: Installing SAAV Into Existing Inclinometer Casing

Q. Is there any after-sale support?

Jeff Barrett

A. Measurand prides itself on working with our clients throughout the entire lifecycle of their project. We are happy to provide technical support at any time. Our Support website is a great first stop for documentation and provides users an easy way to reach out to us directly: support.measurand.com.

Nate McGee

A. The sensemetrics support team provides guided assistance for connection and management of any sensor,  from initial guidance during project planning and design, through implementation and long-term monitoring. Helpful knowledge base articles and access to our highly-skilled support team can be found at support.sensemetrics.com.