Monitoring question
The management or diagnostic problem the system must answer.
Technical guide · Structural monitoring
Monitoring systems and SHM sensor networks
An SHM system is not a sensor: it is a network designed to answer a question over time.
A single sensor measures one quantity at one point; an SHM system organises sensors, acquisition, data management and interpretation to follow the structure's behaviour.
From single sensor to system
Tiltmeters, strain gauges, crack meters and accelerometers provide point measurements. They become a monitoring system when chosen, positioned and managed around a precise question.
Network design therefore starts from the objective: which quantities matter, where to measure them, for how long, and how to deliver the data to decision makers.
Elements of an SHM system
Quantities and sensors
Tiltmeters, strain gauges, crack meters, accelerometers chosen by quantity.
Installation
On-site installation, including sensors embedded in reinforcement before casting.
Acquisition
Data loggers collecting measurements continuously or at intervals.
Data management
Checking, organising and processing time series.
Thresholds and reporting
Alarm thresholds where the system provides for them; reports for the client.
How a network is designed
- 01Question
- 02Quantities
- 03Sensors
- 04Installation
- 05Acquisition
- 06Data management
- 07Analysis
- 08Interpretation
- 09Reports and deliverables
The number of sensors does not measure the quality of an SHM system: what matters is consistency between question, quantities, positioning and interpretation.
Components in the field
Sensor and acquisition
Biaxial tiltmeter and Novatest acquisition unit to track rotations and displacements.
Sensor embedded during construction
Sensor placed in the reinforcement before casting, bringing the element into the system from the start.
Related methods
The monitoring areas a sensor network can support.
Static monitoring
Deformations, rotations and cracks.
Dynamic monitoring
Vibrations and dynamic response.
Modal analysis
Natural frequencies and mode shapes.
Non-destructive testing
Point-in-time surveys of materials and geometry.
Frequently asked questions
- What is the difference between a sensor and an SHM system?
- A sensor measures one quantity at one point; an SHM system organises multiple sensors, acquisition, data management and interpretation around a question.
- Which sensors make up a network?
- It depends on the quantities to observe: for example tiltmeters, strain gauges, crack meters and accelerometers.
- Does an SHM system send alarms?
- It can when the system is designed with alarm thresholds, agreed with the client, on the monitored quantities.
- Where does design start?
- From the management or diagnostic question: only then are quantities, sensors, positioning and reporting chosen.