KudoZ: term help for translators

The KudoZ network provides a framework for translators and others to assist each other with translations or explanations of terms and short phrases.

French term

Miranda Joubioux (X)

591 questions

caisson

French to English Tech/Engineering Construction / Civil Engineering

target=uk

Context: Article about the construction of a museum

D’une largeur d’environ 3 mètres, ce péristyle est composé de 417 colonnes de 17 mètres, en béton fibré ultraperformant, moulées dans une matrice de troncs de pin, légèrement inclinées et disposées sans alignement.
140 d’entre elles supportent trois dalles composées de poutres orthogonales formant caissons, sur une portée longitudinale de 45 mètres sans appui intermédiaire, dans un hommage savant à l’architecture et à l’ingénierie romaines.

Aby ideas how to translate 'caisson' here?

I know there are many examples of 'caisson' on KudoZ, but I can't find one that seems to fit.

Proposed translations (English)

3 +1	boxes	JaneD
4	caisson	josephineterese
3	Rows	Manoj Chauhan
3	box girder	Sylvie LE BRAS

Change log

Apr 9, 2013 06:21: Miranda Joubioux (X) Created KOG entry

Discussion

Miranda Joubioux (X) (asker) Apr 9, 2013: After a long discussion with Bourth (who is sorely missed), I decided to use 'coffers'. Thank you all for your suggestions.
chris collister Apr 4, 2013: Since the beams are orthogonal (presumably mutually orthogonal), then where they cross (underneath the "dalle") they will form box-like cavities.