Filigree concrete shells at the central station in Berlin
Berlin Central Station, opened in 2006 near the city centre was finally connected to the capital's tram network in 2016. Over the course of this extension an important transfer point emerged in the form of a new tram stop at Europaplatz.
To cover the two platforms and offer weather protection to waiting passengers, long stretched, curved reinforced concrete shells were developed. At a size of 58 m × 6 m the two symmetrical, cantilevered roofs are additionally supported on several points by steel columns along the outer edges. They emerge as an extension of the centrally arranged vertical escalator walls, which lead to the future subway station. Due to complex conditions, not only the design and dimensioning of the roofs were a challenge, but also to establish a safe and stiff foundation for the roof structure.
The curvature of the roof surface allows for a load‐bearing behavior of a shell in which bending moments are minimized. By using high‐strength but lightweight concrete (LC45/50 in accordance with DIN EN 1992) combined with a stainless steel reinforcement it was possible to create an extremely slender concrete shell measuring only seven centimeters along the inner edges.