Understanding how forces act: Azure IoT helps fischer carry out continuous structural monitoring and thus enhance safety

The challenge: Visualizing the invisible forces acting on bolt connections

When a bolt is tightened, it’s not immediately apparent what forces are acting on it. In many cases, this makes it difficult to know whether all the design assumptions and monitoring models developed in the planning phase match up with the reality. Of course, this dilemma doesn’t just affect individual bolts—it also applies to all kinds of large-scale structures, including buildings, bridges, and even wind turbines. That’s why these structures need to be inspected by experts at regular intervals, for example as part of a legally mandated structural assessment. This ensures that any damage is evaluated and documented. As the industry progresses with its digital transformation, structural health monitoring is becoming more established. This is about continuously monitoring structures—automatically capturing, processing, and evaluating sensor data with a view to detecting any changes in the structure at an early stage. “The more you know about a building’s condition, the more accurately you can judge whether or not a system is still operating within its nominal parameters,” says Dr. Daniel Rill, Product Manager at fischer.

There are plenty of commercial measurement systems available to perform this function. However, most are tricky to install, operate, and manage and require users to invest significant time and effort. “We weren’t interested in a specialist, stand-alone solution. What we needed was an end-to-end system with a low barrier to entry and that covered everything from the hardware to the software,” says Marc Klunzinger, Product Owner at fischer. “We wanted the ability to digitally model the entire process while providing our customers with an easier and faster way of finding the information they need.” The result was fischer Construction Monitoring. Core elements of this solution are SensorAnchor and SensorDisc: two fastenings equipped with sensor technology that are used in conjunction with a smart monitoring tool. “We saw this as an important investment in our company’s future. In our industry in particular, it’s essential to actively shape change and make early investments in new areas of development,” Rill says. And the company quickly found the right technology to support its latest innovation: Azure IoT.

The solution: Azure brings transparency and alerts to construction monitoring

“Instead of just building a sensor system, we wanted to create an entire IoT architecture,” Klunzinger says. Today, SensorAnchor and SensorDisc are both connected to Microsoft Azure: SensorAnchor transfers information on the forces acting on a fixing to an IoT sensor gateway and transmits this data wirelessly to the cloud. In contrast, SensorDisc monitors bolt preload forces and allows users to access this data on site through the fischer PRO App on their smartphones, which also uploads the data to the cloud. Once all the data reaches the cloud, Azure Event Hub immediately determines whether the measurements should be archived in Azure Data Lake or whether an alert should be sent to the customer, either by email or through the app. Alerts are sent whenever Azure Event Hub detects that measurement data from the sensors falls outside the acceptable limits. “Our customers specify these limits themselves based on their particular application. In some cases, a minimum force will be set as a lower limit, while the upper limit is there to protect against overloading,” Rill says. “Maintenance cycles also affect how these limits are defined. The threshold for triggering an alert can be closer to the limit in systems that are maintained on a regular basis than in systems that are maintained less frequently.”

Analysis of the data can be used not only to generate alerts, but also to make predictions. “Working off the latest measurements, we can tell our customers when we anticipate their specified limit will be reached and how the level of force will evolve between now and then,” Klunzinger says. “Obviously, we also give them the probability of each prediction, with these statements become increasingly accurate as more data becomes available and the closer we get to the limit being reached.” The results are presented to customers through the company’s own front ends, either through the app or in the myfischer Web-Portal. “This enables customers to spot potential risks, damage, and changes early on so they can schedule maintenance proactively. Prompt action can be taken to replace connections that are in danger of failing and to tighten loose bolts,” Rill says. “That makes structures safer while also giving them a longer service life.”

These solutions are already increasing transparency and safety not only in the construction sector, but also in robotics and energy infrastructure. SensorAnchor helps companies that manage, say, wind turbines or overhead power lines clarify whether calculated wind loads correspond to reality. And SensorDisc lets the likes of robot manufacturers assess the remaining service life of their products by analyzing data on the robots’ bolt connections and providing clear feedback on cyclic stresses and maximum loads. “Our customers benefit from a data-driven pool of knowledge, which they can use to further develop their products and directly intervene in upcoming production runs,” Rill says.

Continuous monitoring with SensorAnchor and SensorDisc eliminates the need for separate documentation, because all the necessary data is now recorded automatically. “There’s no longer any need to check bolt tightness and retighten any that you think might be loose. The monitoring systems store all the measurements in chronological order and allow users to access and browse them in real time. So customers can see at a glance whether they need to perform maintenance or any other kind of intervention,” Rill says. “That minimizes unnecessary maintenance, which keeps costs down. It also eliminates unnecessary journeys, which is good for the environment.”

New applications are being identified for fischer’s Construction Monitoring solution every week. “What’s great about Microsoft Azure is that it allows us to scale our architecture incredibly quickly and easily, giving us the agility we need to respond to new customer requests and market requirements,” Klunzinger says. “That flexibility also makes it easier for us to integrate with third-party packages such as building information modeling, or BIM, which is something we’ve already piloted successfully.” BIM offers a connected, software-based method for planning, constructing, and managing buildings. A digital representation of a structure is created by modelling, merging, and recording all the relevant building data. In this context, fischer’s solution offers the same kind of added value, transparency, and safety as it does for individual bolts, but on a much grander scale.