Stringer stairs with stainless steel ring in the TaunusTurm

2017, Frankfurt

A highly polished stainless steel ring encloses the elegant stringer stairs in the TaunusTurm in Frankfurt.

Stringer stairs with glass railings

In the middle of the banking district in downtown Frankfurt am Main, an impressive office tower attracts attention. The TaunusTurm, consisting of a 170 m high office building and a 63 m high residential building, is currently the 12th tallest building in Germany. After the architectural firm Gruber + Kleine-Kraneburg won the design competition back in 2000, it still took two more attempts before the foundation stone was finally laid for the TaunusTurm project in 2012 with Tishman Speyer in charge of construction.

In addition to a canteen, public lobbies and spacious office areas, the base building also houses the technical floor. This will give rise to the residential tower with 50 residential units and the office tower with 40 storeys, which will culminate in two opposing monopitch roofs.

Elliptical stainless steel ring

In a light-flooded office unit, the elegant, single-flight stringer stairs sweep up from the 36th floor to the next floor. The all-glass railings in contrast to the inner balustrade stringers give the steel staircase a playful lightness. The highly polished filigree stainless steel handrail ensures simple elegance, which is further enhanced by the smooth steel soffit cladding. A special eye-catcher, however, is the elliptical ring, also made of highly polished stainless steel, which surrounds the stringer stairs and gives them a sculptural character.


Project details

  • The single-flight stringer stairs consist of an ingenious combination of an inside balustrade stringer in box form and an outside box stringer concealing the treads to accommodate the all-glass railings. The METALLART team of experts welded the steel treads between the stringers.
    • Flight width approx. 1400-1700 mm
    • 22 risers, 21 steps, 1 exit step
    • Design in accordance with DIN 18065 and EN1090 EXC2

The tread construction of the stringer stairs consists of combined folding structure/box treads made of approx. 5-6 mm thick sheet steel.

  • cheek thickness approx. 10-15 mm
  • stringer width up to 60 mm (for grip safety)
  • stringer height approx. 1120 mm at the top from the VK tread and additionally approx. 400-450 mm at the bottom concealing the treads in the same way as the outer stringer

  • stringer thickness approx. 10-12 mm
  • stringer width up to 60 mm
  • stringer height approx. 400-450 mm

  • homogeneous, smooth surface made of sheet steel
  • shaped according to the shape of the stairs
  • welded flush between the stringers on the underside
  • significantly improved statics and better vibration behavior, as statically co-supporting

A small but effective special feature of this stringer stairs is the so-called stringer swing at the exit. The steel soffit lining accompanies this curve with a corresponding bend that deviates from the otherwise even gradient.

  • laminated safety glass panes with a thickness of approx. 20-24 mm
  • pane length up to 1500 mm
  • vertical glass joints approx. 10-20 mm
  • railing height approx. 1120 mm
  • glass railings curved upwards, adapted to the course of the stringer stairs
  • stainless steel handrail approx. 40×30 mm, highly polished stainless steel U-section

The design of the gallery railing corresponds to that of the stair railing with laminated safety glass panes and attached, highly polished stainless steel handrail.

  • design with triangular cross section (isosceles)
  • side length of the triangle approx. 170 mm
  • manufactured in 3 segments, welded
  • ring outline elliptical
  • central axis (length) approx. 6215 mm
  • central axis (width) approx. 4780 mm
  • highly polished

The ring construction was attached to the bearing ceiling construction above the 37th floor with three stainless steel cables.

Architectural office

Gruber + Kleine-Kraneburg, Frankfurt

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