Capital C in Amsterdam wins Dutch Steel Award 2020

The Diamond Exchange, Capital C Amsterdam in the Netherlands has been awarded the Dutch Steel Award 2020. The national monument was restored to its former glory following a major renovation designed by architectural office ZJA in collaboration with Heyligers design + projects. The High Light, an extraordinary and naturally formed dome of steel and glass, glitters on the roof. Distinctive is the way in which the High Light is both an eye-catcher as well as a confident expression, yet made so light that it serves the historical monument. 

A restored monument 
The monument designed by Gerrit van Arkel, which opened its doors in 1911, has largely been returned to its original design with this renovation. Original monumental features have been reconstructed and the two striking towers, the original roof edge and tympana on the roof from Van Arkel's design have been reinstated. The upper 
floor, added in later years, was replaced by two floors with multifunctional spaces under a unique steel and glass dome. The High Light is transparent, light and open and layered with integrated solar cells that not only generate energy, but also provide protection from the sun. This keeps the indoor climate as comfortable as possible. 

Jury Dutch Steel Award 
Jury member Wico Ankersmit: “The restoration of the monument with it being largely returned to the original design by Gerrit van Arkel is a success. After the building was given a modern roof structure in 1990, it has now been carefully restored to its original form and a contemporary volume has been added. The transparent and spherical new roof structure with organic lines is clearly visible on the roof, but at the same time it has a modest appearance. It fully respects the original design of the building, is not obtrusive, but also offers an exciting, contemporary addition. Constructively it is a spectacular design, in which little extra steel has been used. It blends nicely with the monument without appearing pompous. It is an innovative construction with sophisticated detailing. A combination of techniques in design and implementation, and that at an inner-city location. A modern addition to a classical building. It makes sense.” 

Modern versus classic 
The design of the High Light serves the historical monument but is modern in technical and structural design. The spatial dome is independent and recedes behind the façade, standing free from the bell tower. Where the two reconstructed towers are located on the roof, the steel ribs of the dome have been omitted and a green roof terrace has been constructed. The spatial dome is an eye-catcher, but due to its reserved position on the roof and its spatial, transparent construction, it is modest and respectful to the national monument. In this way the monument and dome have become a natural unification. 

State of the art architecture and structural design
The High Light is an example of state of the art architecture and structural design: the dome is a grid shell, which means that the structural strength is provided by the double curvature of the elements. A principle that makes large span possible. The long sides of the dome seemingly connect with existing elements of the monumental building, but these turned out to be unable to absorb the forces from the grid shell. Pieters Bouwtechniek has therefore designed a "giraffe and transfer construction" and integrated it into the design that could absorb the forces from the grid shell, so that the monument remains intact at the height of the roof. The shape of the dome and steel construction were parametrically designed and optimized by ZJA and Pieters in close collaboration. This made it possible to realize the current form of the High Light, not only because it became technically feasible, but also cost-efficient. Moreover, the shape could be generated in a natural, controlled way. Pieters Bouwtechniek is responsible for the structural design and Octatube for the implementation of the High Light.

Crowning on the roof 
With the restoration of the Diamond Exchange, Capital C Amsterdam and the new crowning on the roof, an iconic building has been added to the heart of Amsterdam. With its multifaceted brilliance, the High Light evokes the building's history as the center of the international diamond trade. At the same time, the stylish dome makes the future tangible in form, function and innovative structural design. 
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Capital C Amsterdam 
As Capital C, the Diamond Exchange offers a contemporary office environment and artexhibitions situated within a unique architectural monument. The Diamond Exchange, in its reincarnation as Capital C, has once again become a vibrant and valuable part of Amsterdam.