The expansion of the U-Bahn lines U2 and U5 is currently one of the largest infrastructure construction projects in Vienna. Since the beginning of 2021, construction work has been in full swing and is expected to bring not only 300 million additional passengers and 30,000 new jobs for the two-million-capital after six years of construction, but above all also a saving of 75,000 tons of CO2. That this does not happen without great efforts underground is told live by Swietelsky U-Bahn specialist Wolfgang Friedl.
“I am a huge fan of Vienna's public transport,” announces SWIETELSKY division manager Wolfgang Friedl as a greeting when we take a seat for our interview coffee in the construction office of the Arge U2xU5 Rathaus/Frankhplatz. The reason for this is not only the gigantic underground U-Bahn construction site he oversees, which extends largely invisibly under the Auerspergstraße directly in front of the construction office, with the construction of over two kilometers of tunnel and the creation of numerous shaft structures. And the reason is by no means only that Wolfgang Friedl has been a passionate U-Bahn construction engineer for well over thirty years: “At least since 1991,” he laughs, pointing to one of the many large-format photo panels on the office wall that shows the construction of the U6 in the nineties.
No, the cause of the great love for public transport is additionally a completely different and very personal one, as Wolfgang Friedl commutes daily by rapid transit from his home in Purkersdorf to the construction office and is thus himself an enthusiastic user of the exemplary public transport network in Vienna – “I would hardly ever make the journey by car in thirty minutes, especially not during rush hours,” he recounts. And he travels from Westbahnhof to Auerspergstraße by bicycle, in the spirit of climate protection: As proof, the compact, lightweight folding bike – a stylish Brompton from England – is always within reach against the office wall.
Speaking of climate protection: “We are building together here on Vienna's largest climate protection project – right in the heart of the city,” Wolfgang Friedl proudly announces, simultaneously highlighting one of the many significant challenges of the overall 242 million euro project. Because where the U-Bahn grows underground, some of Vienna's most famous and valuable architectural monuments line the construction route above ground, including, among others, the City Hall, the University, Otto Wagner's famous Truss House at the corner of Garnisongasse/Frankhplatz, and several more.
“The eighty-year-old plane tree in front of Café Eiles on Josefstädter Straße, which had to be carefully transplanted due to the U-Bahn construction, caused a great media echo three years ago,” Wolfgang Friedl recounts. “But what has largely remained hidden from the public eye is the multitude of extremely elaborate construction and safety measures to ensure that the historical building substance of the first, seventh, eighth, and ninth districts along this U-Bahn construction section is not endangered: Foundations had to be reinforced, entire buildings had to be strengthened, and hidden drainage wells in courtyards and basements had to be drilled to ensure the protection of numerous historical buildings in this central city area.”
But that is by no means enough. Because the actual construction measures are an even greater mammoth task with dimensions of superlatives and a start that took place under severely difficult conditions: “We received the order letter in mid-December 2020 and immediately afterwards began as a working group, which was divided into thirds, with our construction section in January 2021 – during heavy snowfall and still in the midst of a major Corona wave,” Wolfgang Friedl recalls a particularly challenging construction start.
The challenges and record performances were just beginning. Because vertically, up to 60-meter-long bored piles were driven into the ground to secure the shafts, which were then excavated. And horizontally, the SWIETELSKY U-Bahn construction even reached record dimensions before the construction section Rathaus/Frankhplatz: During construction work at the U2 station Matzleinsdorfer Platz/Triester Straße in 2018, the so-called modular hydraulic struts for stiffening the shaft walls had to overcome a shaft width of 32 meters. “A specially tailored technical solution for SWIETELSKY that offers significant advantages in construction time and static safety and also makes sustainable sense, as all parts are reusable and, unlike conventional solutions, do not generate demolition debris.”
Impressive alongside the technical achievements is also the human effort at the U2xU5 construction site Rathaus/Frankhplatz: Over forty employees and more than two hundred workers are working on the construction site – especially during the tunnel drives almost around the clock and twenty-four hours a day. “The only dates in the year when our work rests are the traditional Barbara celebration on December 4 in honor of the patron saint of tunnel builders, twelve days during the Christmas holidays, and four days at Easter,” laughs Wolfgang Friedl, “on the remaining 348 days of the year, work is constantly being done at full speed.”
Until that time comes, Wolfgang Friedl will continue to pedal daily on his Brompton folding bike to the U2xU5 construction office: “As a cyclist, you not only do something for climate protection and travel completely CO2-neutral, but you also arrive at work fit and awake in the morning – and that is a great feeling that I can only highly recommend.”
