Base of first pillar cemented in to place for Stuttgart’s future main railway station

SÜLZLE supplies special rebar shapes for Stuttgart 21

Work on Stuttgart’s new subterranean main railway station is progressing rapidly: At the end of July, the first base for one of the supporting pillars was cemented into place, and the formwork was removed successfully. Ultimately, a total of 28 upright supports will be holding up the roof and the gigantic lighting apertures in the future main railway station. In terms of reinforcement technology, each pillar is a masterpiece. The construction company in charge, Ed. Züblin AG, relies on SÜLZLE Stahlpartner as a specialist for high bending accuracy and special rebar shapes. At SÜLZLE’s plant in Denkendorf, situated just a few kilometers from the construction site, a project-specific rebar fab shop was set up. “This is the biggest order in the history of our company”, states Heinrich Sülzle, CEO and main shareholder. “I am convinced that we can resolve the technical building challenges together successfully”.

The Stuttgart-Ulm rail project – also known as ‘Stuttgart 21’ – is one of the biggest construction projects in Germany. The centerpiece involves conversion of Stuttgart’s main railway station, the ‘Hauptbahnhof’ from an above-ground terminus to a subterranean through station. Gargantuan quantities of steel reinforcement bars are being installed in the foundations, floor panels, walls, pillars and ceilings of this building, and in the large number of rail tunnels. This is intended to ensure that all structures can contend with the heavy static loads, as well as with high tensile and compressive forces. By the end of this huge construction project, SÜLZLE Stahlpartner will have supplied about 68,000 tons of steel-reinforced concrete bars and steel rod mats, as well as 100,000 screw connections and braces.

The gigantic pillars are a key feature of the subterranean station concourse. At a later date, these will be supporting the roof, and are also designed to admit daylight. After a sample pillar was tested at the end of 2015 by all parties involved for its strength, color, and surface finish, SÜLZLE Stahlpartner from Denkendorf, the rebar fab shop for this project, entered the crucial phase. The steel reinforcement for the first section of pillar, measuring six meters in height, and known as the ‘pillar base’, presents a special kind of challenge: These bars are finger-thick and several meters in length, and must be bent into position very precisely – not only on a flat plane, but also three-dimensionally. “This is really unusual for steel rebar”, explains Heinrich Sülzle, CEO and main shareholder. “Here, we are testing the limits of what is feasible”.

The first pillar, the top of which measures 32 meters in diameter, contains about 350 tons of rebar. SÜLZLE invested several months in creating these shapes, and invested in new bending machines to accomplish this task. Work is now about to commence on the next pillar base at this huge construction site. Sections of the reinforcement frame have already been installed. The cement for this is scheduled to be poured in August.

The Stuttgart 21 railway project is the largest order that SÜLZLE has ever been awarded in its 136-year history, and demonstrates that logistics can have a crucial role to play. “With orders on this scale, there is often a need to provide large quantities of steel to the construction site on a ‘just in time’ basis”, recounts Heinrich Sülzle. “With our own fleet of vehicles, and the proximity of the S21 project rebar fab shop in Denkendorf as well as our other sites in the surrounding area – at Dusslingen, Pforzheim, Dornstetten and Rosenfeld – we are ideally equipped for this task”. With twelve sites of its own and a partner company in Aichach, SÜLZLE Stahlpartner is one of Germany’s largest reinforcing steel suppliers and has one of the biggest rebar fab shops in the country. It is also in direct contact with a large number of international steel mills.

SÜLZLE Stahlpartner is a supplier to the Stuttgart 21 railway project (photo: Achim Birnbaum)

The formwork has been removed from the first pillar (photo: Achim Birnbaum)

The lighting apertures enable daylight to enter this subterranean structure (photo: Deutsche Bahn)