A new building is slated to join “Europaallee,” Zurich’s master-planned urban sector that surrounds its main rail station. The concrete building will be located on the final site of the development and will be located along a pedestrian-friendly zone on one side and the rail tracks on the opposite side. Wiel Arets Architects (WAA)
Amsterdam-based Wiel Arets Architects has won a design competition to develop “Site D,” a location in the master-planned urban sector surrounding Zurich’s main rail station.
September 10, 2013—Just under a decade after it was initially launched, “Europaallee,” Zurich’s master-planned urban sector that surrounds its main rail station, is once again expanding. Amsterdam-based Wiel Arets Architects has recently been named the winner of a design competition for a mixed-use building abutting the rail tracks and located along the pedestrian-friendly zone.
“As our building is the last of 8 buildings to be built in Europaallee, the relation to the neighboring buildings is of great importance,” said Alexis Bikos, Dipl.-Ing. (architecture), the project leader of the Europaallee project for Wiel Arets Architecture and head of its Zurich office. Bikos wrote in response to written questions posed by Civil Engineering online.
“Our approach, which according to the competition jury was one of the key aspects that led us to win the competition, was to try to accomplish a volumetric connection to all the neighboring buildings in some way and still to achieve a strong solitary form,” Bikos said.
The winning design comprises a four-story plinth and two 6-story towers located within an unevenly angled, quadrilateral footprint. The concrete building will boast shallow depths and good daylighting options so that the towers can either house office space or residential space, depending on the area’s future needs. The competition-winning design calls for an initial two stories of retail topped with eight levels of office space, according to Bikos. The plinth’s rooftop will serve as an outdoor courtyard.
The building’s central plinth will house two levels of retail as well
as a central circulation space. A large, open central staircase
and two escalators will bisect the reception volume. Wiel Arets
The central podium, which mimics the 4-story plinth of the building located to the west of the site, will house the two levels of retail as well as a central circulation space, according to Bikos. The design team created a large, open central staircase and two escalators that bisect the reception area. The third level of the building will provide the entrance points for the two towers and accommodate an entrance hall, a cafeteria, lecture rooms, and other spaces for office functions. However, this story has been designed so that it can be easily converted into additional retail space with the installation of an escalator and the removal of just one wall, should that be desired in the future, Bikos said.
Two concrete elevator and stairway cores located in each of the towers and a prefabricated concrete “sandwich” facade used for the entire building will carry the building’s loads, although a few additional columns will be included in the wide spanning retail floors, according to Bikos. The facade system was chosen because the tight site constraints and the need for the rail lines to remain fully operational while the building was under construction meant that a system that could be installed without external scaffolding would simplify on-site construction, Bikos said.
The prefabricated facade will consist of inner load-bearing concrete columns, insulation, and outer concrete facade frame elements that have been sandwiched together, according to Bikos. A standard office grid of 1.35 m is being used; the shallowness of the grid will be beneficial in creating flexible office spaces.
The building is composed of a 4-story plinth and two 6-story
towers located within an unevenly angled, quadrilateral footprint.
Two concrete elevator and stairway cores located in each of the
towers and a prefabricated concrete “sandwich” facade used for
the entire building will carry the building’s loads. Wiel Arets
At its most extreme point along the eastern side of the building, a cantilever measuring 9.5 m will extend over the adjacent rail lines. The cantilever will be supported by an array of 1.8 m high, 1.2 m wide pretensioned reinforced-concrete beams placed approximately 8.1 m apart, according to Bikos. The beams will be featured as part of the building’s aesthetics, and will be visible in the upper retail ceiling, he noted. The cantilever is included in the design to mimic an existing cantilever in the adjacent building located to the east of the site, Bikos noted, and works to visually tie the building to its neighbors.
A 24 m column-free underground delivery hall that will serve the retail area of the building is located between the site and its neighbor to the east. The structural forces of the entire eastern facade and the two eastern cores must be diverted around this large, underground volume so that extreme forces, such as those generated by an earthquake, will not affect the delivery area, according to Bikos. “To transfer the horizontal loads in this eastern part of the building is one of the main challenges,” he noted. The discussion regarding a solution is currently ongoing, he said.
The Zurich-based structural engineering firm Jaeger Partner AG Bauingenieure advised the architects during the competition phase of the design. Construction of the building is expected to begin by the end of 2016 or early 2017.