VSH Turòa nad Bodvou - Nemetschek Scia

Introduction
The various judicial services of Antwerp urgently needed new law
courts, as they were suffering from an acute lack of space and being
scattered all over the city. At the request of VK, Richard Rogers and
Arup signed up for the public competition for new law courts on
the Bolivar place, organized by the Buildings Agency.
The project of the temporary association RRP - VK - Arup is a
gateway for Antwerp, entering or leaving the city from the south. It
stands on a prominent place, at the end of the “leien” (main streets
of Antwerp), on a location where Antwerp always has had a focal
point, that is ‘The Spanish Citadel (from 1571 until 1894) and the
South Station (“the cathedral of the South”) until 1966.
Furthermore, the law courts project was seen as part of a revitalization
process of the south of Antwerp.
Description
The new law courts are designed as an open house. Large glass
surfaces connect the judicial services with the citizens of Antwerp
and offer marvellous sights on the city. This not only enhances the
transparency, literally and figuratively, but it also insures a good
system of finding one’s way.
Sustainability was another key word. The Buildings Agency stipulated
that they wanted a building that didn’t need mechanical
cooling in the offices. As such, the law courts make an architectural
as well as an environmental statement
The construction counts 6 office wings, placed around a central
public space, the ‘Salle des Pas Perdus’ (Hall of Lost Paces).
From the Bolivar place, a monumental staircase mounts up to this
imposing but light reception space, which acts as an extension of
the public square. From the hall, 6 office wings stretch out (3 on
the left and 3 on the right hand side) and are connected on the
2nd floor through walking galleries. The more public functions are
situated directly near the hall; the parts that are more inaccessible
for the public are situated further down the wings.
In between the office wings, inner yards were laid out, offering a
green sight for the office workers and cooling down the warm air
that flows between the office wings.
With 1 level underground (cells and parking) and 5 levels above
ground, the building measures not higher than 15,75 metres.
The complex circulation-system of law courts, in order to protect
privacy and for security reasons, demands that private and public
circulation are clearly separated. Therefore, the project team
decided to put the actual courts (26 smaller courts and 6 larger
courts) on top of the building, above the offices of judges, administration,
…
In this configuration, the courts almost float above the building
and are crowned with striking cone-shaped roofs. The roofs on the
large courts peak at 41 metres above ground.
Technical data
Public tender organization: Buildings Agency
End user: Federal government service of Justice
Architecture: Richard Rogers Partnership - VK STUDIO - Arup
Duration of the works: April 2001 to October 2005
Surface terrain: 3,7 ha
Gross surface: 78.000 m²
Facade height: 18 metres
Facade width front: 300 metres
Facade width back: 240 metres
Roofs on courts
Start placement roofs: July 2003
End placement roofs: mid 2004
Height large roof: 25 metres (41 metres above ground)
Height small roof: 7 metres (18 metres above ground)
Weight large roof 24 tons
Weight small roof: 18 tons
Gauge inox coating: 0,4 mm
Surface inox coating: 16.000 m²
Roof structure public hall
Start placement steel structure: March 2004
End placement steel structure: June 2004
Measurements: 60 metres x 70 metres
Weight steel construction: 240 tons
Painted surface steel structure: 2.400 m²
Importance, approach and results
Roofs of the law courts
The pointed roofs are without a doubt the most striking characteristic
of the law courts. The applied structural concept, material and
construction method resulted from a thorough analysis, considering
all pros and cons of the various options. Through wind tunnel
tests, the most unfavourable wind charges were determined and
wind disturbance on the surroundings analysed.
The results of the tests, combined with other forces (influenced by
temperature, snow and finishing materials), gave the necessary
data to be able to calculate all structures three-dimensionally.
Also, the calculated distortions of the structures had to be checked
with the compliance of the finishing materials.
At the end, the project team opted for a hyperbolic paraboloid or
hyparscale. This figure has a great advantage: it can be constructed
from linear elements, allowing for a simple method of covering and
coating it.
One roof is composed from 4 connected quadrants (2 high and 2
low quadrants), each a hyparscale in a square base.
The linear elements, as a filling-in of the quadrants, are executed
in a “woven” wood-structure, using planks screwed on top of one
another and fixing them on a centring. This allows for the coating
to follow the curved form perfectly.
Roofs Courthouse Antwerp
The wood-structure is left visible on the inside, for the public to
view the forces within the structure.
During the conception phase, all possible finishing materials were
considered. The hyperbolic paraboloid form of the roofs, specific
connecting details, maintenance demands and sustainability and
the transition from horizontal to slanting planes decided in favour
of inox. Folded stainless strip steel was welded together by means
of a continuous weld.
The quadrant-construction-method made it possible for the roofs
to be constructed completely off-site. After their transport on the
river Scheldt, the segments were connected and mounted in a
minimum of time and without scaffolds.
The pointed roofs act as membranes, all charges are transferred to
the underlying structures through normal forces.
Roof of the central public hall
The roof is a complex spatial structure, composed of triangle
sections. Several junctions and points of support, situated at several
levels in the space, hold the entire roof together.
Eight of these points of support are spatially fixed: they are situated
at the ground level of the central hall, in between the office wings.
Six other junctions are situated at the concrete platforms of the
large courts and are floating. This means the roof structure can’t
be used to transfer the gravitational forces of the six high pointed
roofs of the large courts.
The roof structure is a grid of linear and spatial metal bars,
connected through hinging joints. The pressure of the roof is
resting on the top girders, which are connected with vertical rod
resistors to subtending cables and bars.
Horizontally, the roof offers support for the façade at the front and
the back, but vertically the roof is completely unattached. In other
words, the roof rests only on the 14 points of support mentioned
above, not on the facades.
Footbridges without intermediate support and as wide as the
central hall hang underneath the roof construction. They connect
the office wings on both sides of the hall.
As well as the charges of its own weight, the roof is covered with
doubled-glazed frames and sandwich boards. The glazing is doubly
isolated, in order to prevent condensation.
The most important external charges are snow and wind. In order
to withstand these influences, wind tunnel tests were applied.
A CFD simulation tested the roof structure in case of fire. The results
showed that the temperature of the steel construction would not
rise above 140°C in case of a standard fire, making it unnecessary
to provide the structure with a fire resisting paint.
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