AVS. Arkitektúr verktækni skipulag - 01.12.2003, Page 42

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access is provided to the various
departments of the museum: a work-
shop building and the largely self-
contained exhibition spaces, cover-
ing a total floor area of roughly 2,600
m2. In the basement of the new
building, a connection has been cre-
ated to the existing armoury in the
form of an escalator cut into the
middle of the north wing of the
Baroque structure. A further linking
corridor at ground floor level leads to
a square courtyard known as the
Schluterhof.
The limited site area made it neces-
sary to lay out the exhibition over
four storeys, each of which can be
reached from the glazed hall via
stairs of different design. A gently-ris-
ing, spiral staircase above the glazed
rotunda of the entrance links the first
and second floors. This structure is
of „outstanding“ significance, not
only in terms of its design, but
because it is the only part of the
building that can be seen from the
historical avenue Unter den Linden.
In 1998, during the early stages of
the planning, I. M. Pei’s office con-
tacted the internationally famous
Finnish glass-making firm Tambest
Oy. The feasibility of manufacturing
the three-dimensionally curved panes
of glass was clarified on the basis of
design sketches. From the various
types and qualities of glass produced
by Tambest, Pei chose an iron-oxide
variety for its special brightness and
transparency. This came closest to
his vision of a crystalline construction
material. Tambest was also able to
produce glass with special cusva-
tures for this project. The staircase
facade changes from level to level.
On the ground floor, it is in the form
of a truncated cone. This skirt-like
structure, rotating about a vertical
axis and splayed inwards at an angle
of 10°, confronted both the glass
workers and the frame construction
team with a great challenge. Every
pane of glass in this section is cus-
tom-made and required its own indi-
vidual mould. The moulds had to be
made of steel resistant to high
temperatures. According to the
plans, the prefabricated panes had
to be placed on the moulds in pairs
horizontally. A special powder
mould-release agent was used to
prevent the panes fusing together
during the bending process, when
the glass is heated to 600 °C and
slowly assumes the form of the
mould. Not until the panes are lami-
nated in an autoclave and have com-
pletely cooled is it possible to see
whether the process has been suc-
cessful or whether it has been
impaired by tiny bubbles.
The staircase tower is enclosed in an
inner and outer layer of 12.76 mm
safety glass. The inner skin consists
of 6 mm Eko + glass and a 6 mm
layer of diamond glass. The outer
skin consists of two layers of 6 mm
diamond glass. An intermediate layer
of plastic sheeting was inserted
between the panes of glass in each
skin, and the cavities were filled with-
argon. The largest panes, which
measure 2,800 x 4,300 mm and
weigh 720 kg, are in the ground floor
„skirt“ structure. These elements dif-
fer from the cylindrically-shaped
panes, which have a rhomboid form
and follow the curving line of the spi-
raling staircase. As they ascend the
gently rising stairs, visitors can
admire the facade of the old armoury
building opposite the new museum.
Since even the curved balustrades
are constructed in safety glass, there
is an unimpeded view of the sur-
roundings from all points of the stair-
case. The outer balustrade has a
radius of five metres, the inner
balustrade a radius of three metres.
The sole defining line is formed by
the spiraling, matt-burnishedsteel
handrails.
The closed faces of the strict, geo-
metrical museum building are in
North American granite, French lime-
stone and exposed concrete, finely-
coordinated with each other in
colour. For conservational reasons,
the facades had to remain largely
windowless. On the second floor,
however, they are relieved by large
openings that allow a view to the
outside world and serve as a means
of orientation. Pei directs the lines of
vision to the urban surroundings: a
curved window focuses on a grove
of chestnut trees, the New Guard
House, the armoury and St Hedwig’s
Cathedral. A roof terrace and a
glazed oriel establish visual links with
the museum island. ■
Tambest OY, Lasikaari 1, FIN-33960 Pirkkala,
Tel. +358 (0) 3 3132 3500, Fax +358
(0) 3 3132 3360,
www.tambest.fi.
40 QVS