Dawn view of a pedestrian footbridge ove

Condition Monitoring

What is condition monitoring?

As devices become more and more complex with the years, the need for knowledge of their behaviour become more demanding, as well as the need for accurate data. Predicting the life of a structure today combines the understanding of physics, the detection of physical variables, and the processing of data with computerized algorithms to be able to detect miss function or possible failure. These three concepts form the basis of any condition monitoring system.

By monitoring a parameter of condition (vibration, temperature, strain etc.) information is extracted to identify significant change in the behaviour of the structure which is indicative of a developing fault. Therefore, condition monitoring is a major part of predictive maintenance.

By using this type of monitoring, actions can be taken to prevent substantial damages, or allow maintenance to be scheduled when necessary. The major benefit of condition monitoring is the fact that conditions that would normally shorten the lifespan of a structure can be addressed before they develop in significant failure. Condition monitoring also identifies the type of fault, and the instant when a defect appears in a particular component. This data will provide enough information to improve future designs.

Projects

Condition monitoring on the Taipei 101

The view of Taipei from the 508 meters high Taipei 101, one of the world’s tallest and most expensive buildings is breath-taking. But turn around and you’ll see something equally fascinating: a huge yellow sphere, suspended from eight steel cables in the centre of the building between Floors 87 and 91.

Large civil structures are vulnerable to wind and earthquakes. A strong wind will make the upper levels of the building sway back and forth. This yellow sphere is a device designed to counter these effects of wind and seismic activity on the skyscraper. This is called a tuned mass damper and it weighs 728 ton. A tuned mass damper consists of two components, a very heavy mass, and a shock-absorbing suspension mechanism.

Somni was given the opportunity to install low frequency fiber optic accelerometers to monitor the vibrations and movements of this mass. By monitoring the vibrations, information is extracted to identify changes in the behaviour of the structure which is indicative of a developing fault. But monitoring the vibrations also gives information about the way the structure reacts to wind or for example an earthquake. Therefore, condition monitoring is a major part of predictive maintenance and increases knowledge about the behaviour of the structure

This video show the mass damper sway an alarming distance during the Sichuan earthquake in 2008. 

Sensorbox

Somni also has an integrated system solution for condition monitoring. This is a stainless steel box containing a number of sensors, which together discloses the condition of the structure on which it is placed.

This box is connected with only one fiber to the interrogator, or in case redundancy is required, with two fibers. The box contains two tilt / inclination sensors, three very sensitive accelerometers and a temperature sensor.

With the help of these sensors the condition of the structure can be monitored 24 hours a day, 7 days a week. This measuring includes all the rotations that the object experiences, vibrations in the object, but also displacements are made available.

A very easy to install all-in-one solution that answers all your questions!

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