Infrastructure monitoring reduces maintenance costs

A bridge that was built 50 years ago does not necessarily have the same performance now as it did then. All materials degrade over time and external stresses from e.g. weather and wind can further accelerate this process. Larger volumes of traffic over time can also lead to the bridge being exposed to greater loads than it was originally dimensioned for.

“The same principle applies to all types of infrastructure. This means that it is extremely important to keep track of this for reasons of safety but also because there is a lot of money to be saved in maintenance costs. Continuous monitoring provides a great basis for ascertaining whether the existing structure can continue to be used exactly as it is or whether it needs to be reinforced or replaced,” says Natalie Williams Portal, Doctor of Construction Technology and researcher in Materials and Construction at RISE.

Greater accuracy using sensors

The most common way to determine remaining capacity and load-bearing capacity is through the use of various calculations. But monitoring using sensors can provide a much more accurate overview of current load and how the structure is affected by various types of stresses. This means that the right action can be taken at the right time. Perhaps it would be enough to perform minor reinforcements rather than to replace the entire old structure with a new structure.

“There is currently a certain threshold, as it is not always easy and expert help is often required. But it is worth it. However, many people have probably not yet understood just how much time and money can be saved by monitoring in this way,” says Williams Portal.

Broad area of application

In some countries, such as Spain, it is already common to use sensor monitoring on e.g. bridges. But there are many more areas of applications - ports, roads and underground infrastructure are just a few examples. RISE is involved in several such research projects linked to both academia and industry.

Currently, Natalie's research includes field measurement and validation of an innovative type of rock anchor system to be used for larger onshore wind turbines in Sweden.

"The rock anchor system consists of high-strength steel plates, where we install fibre-optic sensors along the rock anchor, which is then cast into a borehole in the rock with a durable grout. The purpose is to be able to measure, among other things, strains under load and also afterwards. We have installed the rock anchor system in the field at two different locations on the west coast and will carry out measurements in the autumn of 2023 to verify the design and performance," says Natalie Williams Portal.

Can be installed later

Even though it is easier to install sensors from the start, as in this case, it is also perfectly possible to install them later.

“One example is the project we are conducting with the City of Varberg and others, where we are looking at a number of pedestrian and bicycle viaducts. The city is undergoing an intensive development phase and needs to examine whether these are dimensioned for the increased loads that will occur during the construction phase. In such cases, sensor monitoring provides an excellent tool for verifying loads and structural performance,” Williams Portal says.