state office de knoop

The former Knoop military station in the city centre of Utrecht, formerly the headquarters of the Dutch land forces, will be redeveloped into a combined state office and meeting complex over the coming years. Also, a variety of longer and shorter term temporary workplaces for guests as well as a diversity of catering facilities will be realised. An important part of the assignment is the adjustment of logistic flows for the variety of users, that all have their own security levels.

cepezed takes care of the architectural design of the transformation. The office is commissioned for this by the R Creators consortium formed by Strukton, Ballast Nedam and Facilicom, that won the tendering of the DBFMO-assignment with an exploitation term of 20 years. Fokkema & Partners Architecten are involved for the interior design of the new complex and Rijnboutt for the aspect of urban planning.

The original complex, dating from 1989, consists of a characteristic configuration of construction volumes with different heights, varying storey dimensions and meandering facades with sun blinds of smoked glass. The redevelopment combines radical changes to the existing construction with partial demolishment, expansion and a fully rearranged urban setting over several levels of height, which is entirely directed towards a congenial experience and the processing of large volumes of pedestrians. Internally, the former military object will also undergo fundamental changes, with among other things a large variety of contemporary work place concepts. After realization, the inner world will offer the experience of a fluid continuum of functions. 

The new state office will have a lively and transparent plinth of double height with general functions such as the entrance zone, the café, restaurant and short term guest workplaces. The twelve-storey existing construction will hold all office functions while clearly showing its history. The large octagonal concrete columns will remain fully in sight, but the many inner walls of brickwork will disappear for the benefit of more light, air, openness and transperancy. Climate ceilings in the existing construction will do away with the need for lowered ceilings and will offer maximum spaciousness in spite of the limited storey height.   

The meeting centre will be accommodated in an expansion with eight high storeys and an efficient construction of steel and prefab concrete stability cores. The new and existing construction will be connected through a spacious and transparent atrium as well as a transportation zone holding the staircases and lifts. In the meeting centre, the break areas and workplaces for guests are situated towards and in direct connection with the central atrium. For a pleasant, more serene atmosphere, the meeting rooms themselves are turned away from the atrium. 

The complex will have an austere skin with a vertical articulation that will bind the separate construction volumes into an indivisible whole. As a result, coves in the existing building contour will be turned into voids adding to the internal spatial quality. The existing construction will have a facade with a 3:1 ratio of transparent and closed elements. Where the facades enclose current variations in contour, the facade will have the same ratio of transparency and closed elements, but in a somewhat more robust rhythm. The expansion will be provided with higher storeys which will receive sufficient daylight with an open-closed ratio of 1:1. This way, within one and the same facade system, the elevations are characterized by a number of subtly varying appearances adding to visual suspense and refinement. The glass parts of the most upper storey will be positioned a bit backwards in relation to the rest of the facades, resulting in the delicate suggestion of a cornice. The closed facade elements will be finished with aluminum panels, partly executed as grating for the benefit of natural ventilation through the shutter panels behind them. 

Natural ventilation is part of the project's sustainability, which is also an important goal of the redevelopment. Other aspects adding to this are the optimal reuse of the existing construction, a high degree of flexibility and for example the employment of triple glass, certified materials and a green roof on top of the lower part of the existing construction. A large surface of solar panels, use of the existing concrete building's accumulative  mass and an energy concept based on recirculation and  heath recovery are important parts of the energy house holding. Automatic detection of presence for the lighting as well as CO2-measurement for the climatization also add importantly. An advanced energy monitoring will help pushing the energy use back as far as possible during the exploitation.
utrecht / the netherlands