JEC COMPOSITES MAGAZINE - Issue #113 - June 2017 - 41

Between minimalism and baroque: a first in France's construction sector

Holy Trinity Cathedral, Paris
©Alessandra Chemollo

onto the concrete domes. The work operations had to be interrupted when the wind
was stronger than 20 km/h (about 12.5
mph) to keep the lightweight composite
domes from swaying too precariously.
The self-supporting domes required no
additional supporting metal structures.
The end cones were installed last, along
with the Russian-made crosses.

wide-load vehicles. Multiplast took care
of the handling operations - extremely
difficult, as each petal had to be attached
by its lower surface to avoid touching the
upper gilded surface, which was absolutely forbidden!
When the petals were delivered to the
worksite in Paris, they were assembled on
the ground and crane-lifted to be mounted

More information:
www.wilmotte.com

Focus

- Owner: Russian Federation
- Architect: Wilmotte & Associés
- General contractor for project management: Bouygues Bâtiment Ile de France
- Height of the greater cross: 36 m
- Greater dome: 8 metric tons; height: 11.5 m; diameter: 11 m
- Lesser domes: 2 metric tons, height 6 m
- Petal thickness: 5 cm; composite sandwich with polyethylene foam core and glass fibre/epoxy
resin skins
- Gilding foil: Moon Gold; 90,000 thin 8x8 cm squares

No113 June 2017

/ jec composites magazine

Feature Construction

Each unmoulded petal was mechanically
assembled to the others to check for fit,
and then prepared for gilding with "Moon
Gold", an alloy of gold and palladium
(similar to platinum). Multiple primer
layers had to be applied to the fibreglass
substrate to keep it separate from the
90,000 8x8 cm squares of gilding foil that
were placed side by side on the surface
by the journeymen from Ateliers Gohard
- the same workshop that re-gilded the
Statue of Liberty in New York and the
dome of the Invalides. Nothing covers the
foil, however.
Once dried, the gilded petals were reassembled, then disassembled once again
and placed in frames for transport in

A symbol around the world
Despite a rather sensitive context,
everything went quickly and serenely. The
companies involved were highly motivated, and the interchanges with the head
architect for Bâtiments de France and the
Paris municipal administrative services
were very fruitful.
In their exchanges with the workmen and
journeymen, the architects emphasized
the fact that they were working on a
monument and not just on a building. A
monument endures as a visible, recognizable symbol and should be flawless.
Furthermore, in this case, the monument
has a spiritual dimension. Religious
ceremonies took place for the foundation
ceremony and for the consecrations of the
greater dome and the greater cross.
The view of these onion domes from the
top of the Eiffel tower is breathtaking. All
the objectives in terms of the visibility,
beauty, careful detail, simplicity of line
and urban harmony that characterize the
work of Wilmotte & Associés have been
brilliantly achieved.

http://www.wilmotte.com

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #113 - June 2017