Squeezing zone inside the mountain

Manuel has observed the installation of yielding elements on his daily rounds of the tunnel construction site. Up to six elements are installed for each round. Each one weighs around 80 kg and is lifted into position by two men working in a very tight space and often over their heads at a height of four to five meters – a process that takes extraordinary strength. “It is extremely difficult work: laborious, exhausting, terrible ergonomically, and always a safety risk,” explains construction manager Markus Viertler.

“Things happen at work where you think: that can’t be the solution!” says Manuel. “This was one of those cases. I already knew quite a lot about yielding elements – and I wanted better ones than those available on the market at the moment.”

And the construction engineer already had a solution in mind. “From my studies, I knew that EPS/polystyrene can replace steel in a lot of applications, such as when used as perimeter insulation underneath foundations,” he says. “I wanted to try it out.” The Semmering construction site has its own small laboratory. He ordered materials to be delivered there and began testing new solutions – mostly in his free time.

Further tests in the tunnel were also persuasive. The new element performed impressively on a 10 m test section. Not only that: the conventional steel yielding elements proved inadequate on a technically demanding section of the route. 650 of the new elements were installed there in consultation with the ÖBB, and have been performing impressively ever since.

Interested in the new compression element? Write to Manuel Entfellner

If they are to be added to the official materials list for the project, the elements also need to be subjected to loads in the laboratory that prove they can guarantee a life span of 150 years. “In the next step, we will apply the test results in order to extrapolate to 150 years,” says Manuel Entfellner. The product will then be ready for the market.

“Many colleagues were sceptical at first,” says Manuel, when asked how his working environment reacted to his love of innovation. “Luckily, two people were right behind the idea from the word go and really supported me: our geotechnical expert Helmut Wannenmacher and Rudolf Knopf, Head Tunnelling Austria.”

Rudolf Knopf loves working with his dedicated team and actively supports initiatives that aim to create cheaper and better products. “It was like a protected market for yielding elements, with inflated prices and unsatisfactory quality. The solution for this field is hugely welcome. I always support it when people come with good ideas. After all, ‘not possible’ is not in our vocabulary!”

Rudolf Knopf also encouraged Manuel to submit his suggestion to Implenia’s in-house innovation programme, Kickbox. Since then, the team at the Implenia Innovation Hub has supported him in patenting the product and preparing for the market roll-out. Other companies are also interested in the solution.

Manuel Entfellner, 29-year-old tunnel constructor and intrapreneur, can soon expect to see his development being used not only in his own project, but also enhancing tunnel construction far beyond Austria’s borders. And that is no bad thing. “The trend for putting more and more roads and railway tracks underground is making tunnel construction an ever more important discipline,” says Rudolf Knopf with conviction. «Innovative minds like Manuel Entfellner are making sure that we at Implenia not only deliver good work, but are playing a significant role in shaping the way construction will look in the future.”