With much of its focus being on-site tasks for discrete projects, Skanska has been looking at ways to automate aspects of the build process to make them safer, faster, and more adaptable.
One area the company has been investigating is using robots to produce cages of reinforcement bars (rebars) that help to hold concrete structures together. As a time-critical operation, the time required for this operation can have a significant impact on the duration of a project, with all work needing to be done before the main construction stage can get underway.
Trials using ABB robots and ABB’s RobotStudio offline programming and simulation software, have met the goals of improving the speed and efficiency of the rebar cage manufacturing process. Overall, Skanska has reduced the time needed from 16 hours per tonne to just 1 hour per tonne.
The vast decrease in production time of this fundamental component will help to significantly improve project time schedules, with less time needed up front for the rebar process.
Another major benefit will be reducing the number of people involved in the rebar process, allowing workers to be used for other tasks and projects – this factor is particularly important as it is growing increasingly difficult to find workers that want to do these sorts of tedious and demanding tasks.
Ulf Håkansson, Skanska’s head of design management, innovation and former technical director, says: “When it comes to safety and automation, it is crucial to automate certain tasks that result in a lot of injuries and where people are doing tasks they shouldn’t be doing. Building rebar cages is one of these - it is perfect for robots and automation and when performed in this way, it can improve health and safety significantly.”
"The crisis with resources is enormous"
After efficiency and reducing the time needed for constructing rebar cages, Skanska sees skills shortages and the lack of resources as the second most important factor driving automated construction. Says Håkansson: “The crisis with resources is enormous – we have found that robots are the key solution to solving the problem of a shortage of skilled labour. Another factor is that young people are not interested in doing these tasks manually.”
Sustainability of construction is another major issue for Skanska. “We have seen in the automated manufacturing of rebar cages that you can minimise transportation and the associated pollution, as we don’t need to import cages by truck or boats from outside Sweden,” says Håkansson. “We can build them in Sweden using robots on site and truck them a short distance to where they are needed - efficiency is therefore much higher by manufacturing things on site.”
"The benefits will be much higher than the initial cost"
The cost of automation may discourage some companies from going down this route, but Håkansson insists it is worth it: “By introducing automation there will be an upfront cost, but the benefits will be much higher than the initial cost. With the rebar cages, we had to put more time into design because 3D models had to be created as a digital twin, but we gained benefits many times over in terms of the production time saved.”
For the future, Skanska’s vision is of flexible, movable factories that can go where the work is. Says Håkansson: “Our work is project based, so what we set up will not be like a Tesla factory – we will need flying factories that are site based. We will also need robots to be mobile and able to move around and possess sensors to know where they are.”
- Reduction in time to make rebar cages from 16 hours a tonne to one hour a tonne
- Helps address skill shortage and improves worker health and safety
- Onsite production avoids need to construct rebar cages outside Sweden, cutting transport and pollution
Skanska in brief
- Operations: Construction and Project development, including Residential Development and Commercial Property Development
- Operates in the Nordic region, Europe and USA
- Employees: 32,500 (2020)
- CEO: Anders Danielsson