Page 169 - ELEMENTS EUROPA (EN)

ELEMENTS EUROPA
cradle’s perforated steel sheeting gives it a certain transparency
while at the same time hiding the lift motor and the trolleys
when in parking position.
Battery recharging is done automatically via a contact box
attached to the walkway, which is switched on as soon as the
system reaches its parking position. The charger itself is on an
electric panel located at short distance inside the building. The
parking position is exactly in front of a door opening onto an
inside staircase and providing easy access. The door is equipped
with the necessary access control and locking systems.
Two trolleys are positioned on the support rail alongside the
cradle, each equipped with a safety line. One of the trolleys
always goes with the cradle, serving as a back-up should the
system break down and the operator be unable to get back.
The other one remains next to the access door, for use by a
rescuer needing to get to the operator in the case of the latter
becoming ill.
SYSTEM B: THE INSIDE SURFACES OF THE ATRIUM’S DOUBLE
FACADE
The two glazed facades, each with a surface area of nearly
4,000 m², are some 3 metres apart. They enclose the facade’s
twin metal structure, connected on each floor, i.e. every 3.54 m,
by braces and diagonal struts. On each of the ten floors
concerned, maintenance access to the two facades is by
a “cage” running along two rails fixed to the braces.
In the course of the design phase, the concept was constantly
refined, finally taking the form of a simple parallelepiped with
a double floor. The upper floor is just one metre above the
lower floor, but can be raised in three parts. It is reached by
raising the middle part, while the lowered side parts constitute
the platforms used when working on the upper sections of the
two facades. Vice versa, when the two side parts are raised,
the operators have access to the lower sections of the facades
through standing on the lower floor.
The back and front of the cage (the sides not facing the
facades) are closed by perforated steel sheeting, and the front
has an access door. The sides are open towards the facades
to be cleaned.
The cage’s width and depth allow it to get around the
north-east corner of the double facade without touching
the structure.
MECHANICAL MANOEUVRING 165
Electric motors propel the cage along the rails, getting their
power from on-board batteries under the cage’s floor. They are
automatically recharged when the cage is in parking position.
On the eight lower floors, the building’s configuration allows
the cages to be parked behind double doors fitted with mirrors,
making them invisible from the atrium and the Rue de la Loi.
On the three highest floors, the cages park in the south-facing
double skin.
SYSTEM C: THE INSIDE SURFACE OF THE ATRIUM’S DOUBLE
FACADE
The facade’s smooth vertical design allows the use of a
conventional cradle suspended from a monorail, though
access to the system is not conventional: a small terrace with
a guardrail hidden by a mirror has been discretely fitted into a
hollow on the 11th floor. This provides access to the System
C cradle, as well as, via a permanent ladder, to the grating
closing the lower side of the atrium’s roof structure. A short
rail runs from this terrace, ending at a motorised set of points
connecting it to the monorail running along the whole facade.
SYSTEMS E AND G: THE LANTERN’S CONCAVE-CONVEX FACADE
Right at the start of the detailed design stage for the lantern,
the question was raised about how to clean its outside facade.
Its concave-convex geometry, half of it overhanging, made it
impossible to use a conventional suspended cradle. In addition,
the payload of the atrium floor slab where it covers the railway
tunnel is limited to 500 kg/m², prohibiting the use of a heavy
mobile elevator capable of reaching the top of the lantern,
some 40 m high.
Two different systems are therefore used, one for the
overhanging lower part, the other for the receding upper part.
The elevator providing access to the lantern’s lower part
(System G) is a standard lightweight machine on caterpillar
tracks able to reach all places on the lower half of the lantern
without its weight exceeding the floor’s maximum payload. The
effect of the elevator’s caterpillar tracks and stabilisers on the
atrium’s parquet flooring was tested in detail (cf. “The atrium
floor” on p. 140). The elevator is painted white, like most of
the other systems. Considered an integral part of the building,