54
EUROPA
Introduction
No, the life of the engineers of SECO’s
technical control office is not one long
peaceful river! And certainly not for the
mission the
Régie des Immeubles
entrusted
us with for this project under the leadership
of Philippe Samyn & Partners, with Studio
Valle Progettazioni and Buro Happold Ltd.
A design or execution fault may jeopardise
the soundness of a project, its thermal and
acoustic performance, even the security of
its occupants. The technical control of the
structures is first and foremost aimed at
preventing these risks.
The technical complexity and the level of
expectations are very high in this case. It
involves one of those projects of which one
is proud to have been part of in one’s career
as an engineer. No room for approximations.
For each question posed, several solutions
are considered, even non-conventional
ones, out of the box, in order to optimise
results. For example, for the protection of
the “lantern’s” external structure against
potential fire, at one point it was considered
to resort to the irrigation of the metal sec-
tions. This solution was subsequently ruled
out after a feasibility study.
It would be easy for the technical inspector
to reject any innovative solution and to
only approve traditional solutions. This is
nonetheless not our philosophy. On the
basis of our vast experience, including new
technologies, we, on the contrary, aim to
assist, in a constructive spirit, the authors of
projects and contractors in their tweaking
of optimal solutions, in the interest of the
contracting authority. Similarly, we actively
participate in applied research programmes
and we share our knowledge as part of the
elaboration of Belgian and European techni-
cal standards and university and engineering
school teachings.
Structural transformation of an
existing building
The structural transformation of the
Rési-
dence Palace
, a prestigious building erected
in the 1920s, represented a true technical
challenge. This building had been extended
in the 1960s. As part of the current project,
this extension was torn down, as well as a
portion of the adjoining building dating back
to 1920.
Columns have been removed in the base-
ments whilst they still supported higher
floors. Elsewhere, adequate phasing has
allowed to demolish existing foundations
that supported ten floors but that were
located in the outline of an additional base-
ment to be created. In order to allow for the
construction of new basements, temporary
ground retaining walls were created and the
existing foundations were reinforced.
The section of the
Résidence Palace
that was
eventually preserved is made up of outer
façades and a thin strip, five metres wide,
over a height of 10 floors! Rigid transversal
elements, which ensure the horizontal
stability of this slender structure were torn
down. Three staircases as well as a corridor
on the ground floor, on the other hand, have
been preserved.
In order to allow for the demolition, it was
necessary to first create new core bracing
in reinforced concrete, through the existing
structures. Subsequently demolition was
started, from top to bottom, level by level,
with the horizontal shoring up of the section
to be preserved on new concrete core walls.
Then new floors were built, from bottom
to top, with the progressive removal of the
shoring.
Under the preserved section, a railway
tunnel had to be excavated as part of the
metro construction. In order to allow for
the excavation of this tunnel, on which the
building cannot lean, four metal trusses
measuring 8 metres in height covering a
22-metre span were assembled between
the first and third floor, as part of this
construction site. The building, i.e., the
preserved section and a stairwell, were
subsequently suspended from these beams,
which allowed for the demolition of the
lower ground floors and the foundations
within the tunnel’s boundaries.
It goes without saying that in order to
bring this type of project to a successful
conclusion, collaboration between all the
parties is critical. Various aspects that are
not necessarily similar must be reconciled,
i.e., stability, technical execution, economy,
planning, architecture, etc.
The task of the technical inspector is to
facilitate the development of solutions,
including instances when non-conventional
issues are encountered. Special attention
was also paid to the follow-up of the
execution during tricky stages, such as the
construction of a slab, 86 cm thick through
the building’s load-bearing walls, a slab that
was subsequently suspended from the metal
trusses above the metro tunnel.
Text drawn up by
SECO
and coordinated
by
Pierre Spehl
, engineer
TECHNICAL CONTROL
FROM RéSIDENCE PALACE TO EUROPA
