A structural health monitoring (SHM) network can be a valuable tool for tracking short- and long-term changes to the performance of a structure. Such systems are useful for ensuring that a structure is safe during construction and throughout its life as the materials age. SHM systems are often used on:

• Roads
• Bridges & overpasses
• Buildings
• Dams
• Retaining walls
• Other large structures

SHM systems may be either portable for short-term testing or fixed systems for remote or long-term applications. A fixed system consists of one or more data loggers and a series of sensors. There may be just a few sensors, or systems can be expanded to incorporate a large amount of various types of sensors. Data communications can be through direct connection to on-site processing systems or be through telecommunications including cellular and radio.

Data Logging & Management

The selection of a data logger depends on the devices and parameters that must be monitored. For many projects, the Cautus Logger is a cost-effective system that provides ample sensor inputs for a wide range of commonly used devices, including a camera for taking photos of the project area. Each device is sampled manually or automatically at a defined interval. An integrated GSM/GPRS modem allows for remote configuration and transmits data in real-time.

Data is received and displayed on the Cautus Web, an online system with many tools for project management. Raw data may be processed through algorithms to output results and displays in the desired units of measure. Alarm capabilities notify project personnel when threshold conditions are met or exceeded.

Data loggers from Campbell Scientific are also popular for use on SHM systems because of their ability for advanced controls and programming. On-board instructions can contain the algorithms used to process data, and measurement triggers can be based on sensor output, time and/or user control. For example, if an overpass is being monitored, data collection can be triggered by a sensor detecting the approach of a car, an earthquake, pre-programmed times, or by pushing a button. External controls allow them to sound alarms, actuate electrical devices, shut down equipment based on time or measured conditions, or call phones and other devices to report site conditions.

Sensor Selection

A very large range of devices may be used together to gain a complete overview of the structural conditions. Some of the most common devices are listed below:

• Strain gauges
• Accelorometers & tiltmeters
• Extensometers
• Jointmeters
• Crack meters

The available data logging options also allow for expansion with devices to measure extraneous parameters such as weather conditions or water heights that may cause responses on the structure being monitored.

MeasureIt can provide data loggers and sensors used for structural health monitoring both individually or as a complete system. Click the links in the text above for more information on the devices, or contact us to share information on your project and receive equipment recommendations.