Digital Monitoring Systems To Detect Building Structural Changes & Defects
- Building Associations
- Engineering / Architecture firms
- Local Building Inspectors
Especially For Buildings On Soft Ground
Building collapse, a global phenomenon. In most cases, building loss could be prevented if they followed engineering reports on time. However, in many cases, engineering reports are prepared based solely on visual inspections, often lacking digital measurements as solid evidences of building movements or changes in the concrete / steel rebar support structure over time. With new digital tools, these visual reports can be considerable enhanced and prioritized for appropriate action and repair.
What are the common movements to a tall building?
A Building experiences more prominent movements due to vibrations and in all three (X-Y-Z) axis. Vibration occurs due to natural ground movement, natural forces such as winds and storms and, due to heavy construction work close by which inflicts extra vibration and movement.
Vibration in the building movement is often imperceptible, but can be measured through digital sensors attached to the building.
Anther common movement is ground settlement which may settle the building too which can also be measured through digital sensors
vertical position. Costal buildings settlement may also cause water table problems with the foundation.
What’s needed to digitally monitor a building?
In the past, building inspectors, engineers, have relied on detailed engineering observations. However, modern digital sensors can acquire precise data on the building movements, can compute and quantify the movements and complement the engineering inspectors by providing them with hard evidence. Following are the types of most frequently observed movements, its indications and type of digital sensors that will help in capturing the movements i.e. direction, quantity and time.
|Movements and condition to be captured||
|Signaguard Sensors or devices to capture movements ongoing basis|
|# 1||Ground and Building settlement||Settlement i.e. subsidence over years. Settlement may be very less initially; however, it can be rapid as well if foundation and soil conditions change rapidly||Liquid Level Sensor helps in capturing the settlement|
|# 2||Tilt or Inclination of the building from the vertical position||Building may get tilted over time due to multiple conditions being of the building health or soil conditions||Inclinometer helps in capturing and measuring tilt with respect to the vertical axis|
|# 3||Building vibration, to n from movement, esp. in X/Y axis, amplitude and frequency of vibration||Building vibration and sway movements happen due to winds, storms, nearby constructions, etc. As the building ages, the amplitude of vibration may increase gradually. It is important to capture excessive movements||Accelerometer & Deflectometer sensors help in measuring the amplitude, frequency of vibration movement|
|# 4||Spalling and corrosion of concrete||To be captured through photography and videography from inside the building or outside. Visual inspection from inside and drone’s photography outside||Drones and Visual|
|# 5||Rusting and Corrosion of Steel inside the concrete||To capture corrosions inside the rebar / reinforcement steel inside the concrete.||Ultrasonic sensors may be used as a Non-Destructive Testing|
|# 6||Salinity and Acidity||To capture from the air||Sensors|
|# 7||Ground Water Table movement||To capture Ground Water Level movement and change over time||Geotech reports from Govt Agencies and Consultants|
By combining visual engineering inspections with ongoing digital monitoring solutions, building owners can better understand the vibration, deflections, permanent changes, resonance effect, changes in possible elastic properties of a structure which in turn may avoid loss of building and lives.
What Are The Indications Of Impending Danger And Possible Collapse?
There may be multiple reasons for tall building collapses, full or partial. It requires detailed engineering investigations and forensic testing of the concrete and steel remnants, geotech reports of the area, etc. However, there will be a set of manifestations that will indicate certain appropriate measures to be taken in advance:
- Indication #1: Gradual ground and building settlement over years and rapid settlement in a short period before the collapse.
- Indication #2: Tilt of the building. Excessive and comparatively rapid tilting may call for suitable action.
- Indication #3: Spalling of Concrete and Corrosion of Steel rebars inside the concrete, especially at the lower part of the building and basement which will make the building weak.
- Indication #4: More frequent and excessive perceptible and imperceptible vibration and deflection due to winds, storms, nearby constructions, etc. As the building ages, the amplitude of vibration may increase which also indicates a gradual weakening of the building structure.
- Indication #5: Sharp change in vibration characteristics i.e. frequency and amplitude, may be an indication to investigate further and act.
Current methods of monitoring are more visual and manual, carried out at a long interval that does not capture the time sensitivity of the above indicators. Manual methods using discrete data sets are not enough to indicate impending issues of structural health which often is a gradual process and may indicate some sharp characteristics.
Therefore, it is imperative to adopt Digital solutions to understand the vibration, deflections, frequencies of deformations, permanent changes, resonance effect, changes in possible elastic properties of a structure which will throw indications as mentioned above to prevent disaster.
The Signaguard Tall Building Monitoring System: How does it work and help?
SignaGuard Building Monitoring system is IoT (internet of things) based SHM (structural health monitoring) system that includes fit for purpose Edge-Sensors, Cloud based software to process big data, advanced analytics and powerful visualization on laptop and devices.
The SignaGuard SHM solution monitors building vibration, deflection or amplitude, differential ground settlements, tilt of the building and measures the movements quantitatively. The SignaGuard solution uses edge analytics, sends SMS/Email alerts which may be event based or at a predefined frequency. All data can be seen on mobile app as well.
SignaGuard Artificial Intelligence and Advanced Analytics work to help understand progressive building behavior to assess structure and providers valuable insight to building engineers and managers.
How does SignaGuard help visual the building structural health?
SignaGuard has a scalable multi-tenanted software securely hosted on Microsoft Azure Cloud. It has a Big Data Analytics engine to process large volume of IOT / Sensors data. SignaGuard uses its own algorithms to process, extracts feature and shows the condition of the building movement quantitatively in absolute terms and rate of change.
SignaGuard’s standard graphical descriptive dashboard shows the vibration, deflection and its amplitude with respect to time to provide an understanding of building’s movement, frequency and its inclination. It captures the progression also with respect to time
SignaGuard’s Advanced Analytics Dashboard helps to understand the patterns of movement. It also captures the progression of movement under similar variables such as weather conditions. Building owners or authority should always seek experts’ opinions for full analysis.
How Does SignaGuard Approach Building Structural Health Monitoring?
- Adopt the SignaGuard digital solution to monitor some items 24/7 and some periodically.
- Install the sensors appropriately and connect them with the cloud-based software to process huge volumes of sensor data.
- Monitor the vibration frequencies, amplitudes, ground settlements and sharp changes in any of them using simple a visual dashboard on a computer screen and / or mobile device.
- Get alerts when predetermined threshold limits of movements are observed by sensing units.
- Optionally, use Advanced Analytics, based on the sensor data, photographs, 3D scan/point clouds and other inputs to throw light on the progressive deterioration of a structure.
The SignaGuard digital solution takes a close look at the data through Advanced Analytics. The data-driven approach may indicate the causes of the potential problems. However, it is important to remember that advanced analytics works on probability and sufficiency of data. It is not foolproof but may improve the methods and objectivity of monitoring.
What Is Needed to Measure & Monitor and At What Frequency?
- Accelerometer: To measure 24×7 the vibration, frequency and deflection
- Liquid Level Sensor: To measure building settlement into the ground at an appropriate frequency or once a quarter.
- Inclinometer: To measure the tilt of the building. It is preferred to obtain data once a quarter for a critical structure once a month or appropriately
- Drone Photography of the external surface of a tall building which may not be accessible easily and by manual inspection.
- Signaguard Software and Data Analytics Platform to collect all the data, process it and visualize the indicators of health.
Optional, Advanced Analytics by Data Scientists and Structural Subject Matter experts to provide more possible reasons, if appropriate.