Concrete beam collapses across track at Gare d'Austerlitz, Paris.

[2HAP]

Traffic at the Gare d'Austerlitz, Paris is disrupted after a large concrete beam collapsed across the tracks.

SNCF : une poutre tombe sur les voies près de la gare d'Austerlitz, le trafic pour le Limousin perturbé

Suite à un incident sur un chantier de BTP, un coffrage destiné à la réalisation d’une poutre est tombé, ce mardi 1er décembre, sur les voies de la gare d'Austerlitz, situées en contrebas. Les trains pour le Limousin au départ...

france3-regions.francetvinfo.fr

SNCF : une poutre tombe sur les voies près de la gare d'Austerlitz, le trafic pour le Limousin perturbé​

Suite à un incident sur un chantier de BTP, un coffrage destiné à la réalisation d’une poutre est tombé, ce mardi 1er décembre, sur les voies de la gare d'Austerlitz, situées en contrebas. Les trains pour le Limousin au départ de Paris sont déplacés à la gare de Paris-Bercy.

Translation:-

SNCF: a beam falls on the tracks near the Gare d'Austerlitz, traffic for Limousin disrupted​

Following an incident on a construction site, a formwork intended for the realization of a beam fell, this Tuesday, December 1, on the tracks of the Austerlitz station, located below. Trains for Limousin departing from Paris are moved to the Paris-Bercy station.

 

[MarkyT]

Translation:-
... a formwork intended for the realization of a beam...

From the tweet with the picture linked in the article and replies, this was not formwork, but the final beam itself, weighing around 400t, so possibly a serious structural failure in a permanent component of the over-track development! Maybe formwork had been removed prematurely before newly poured concrete was capable of supporting itself?

https://twitter.com/BB27000/status/1333662220450979841?s=20

Chute d’une poutre de @VINCIConstruc sur les voies à Austerlitz.

Translated: Falling beam from @VINCIConstruc on the tracks at Austerlitz.

 

[LNW-GW Joint]

From the tweet with the picture linked in the article and replies, this was not formwork, but the final beam itself, weighing around 400t, so possibly a serious structural failure in a permanent component of the over-track development! Maybe formwork had been removed prematurely before newly poured concrete was capable of supporting itself?

https://twitter.com/BB27000/status/1333662220450979841?s=20

Translated: Falling beam from @VINCIConstruc on the tracks at Austerlitz.

Vinci being part of the BBV JV, the contractor for much of the northern part of HS2 Phase 1.

 

[DelW]

From the tweet with the picture linked in the article and replies, this was not formwork, but the final beam itself, weighing around 400t, so possibly a serious structural failure in a permanent component of the over-track development! Maybe formwork had been removed prematurely before newly poured concrete was capable of supporting itself?

https://twitter.com/BB27000/status/1333662220450979841?s=20

Translated: Falling beam from @VINCIConstruc on the tracks at Austerlitz.

It looks like a tension-zone failure, so unlikely to be under-strength concrete (which would be expected to fail in compression above the neutral axis). They're also more likely to have been precast elsewhere rather than poured insitu.

If anything I'd suggest it may be a problem with bottom flange reinforcement or pre-stressing, though either would be unusual in precast beams. Unless there's a more obvious explanation, that implies a concern about similar beams already in place as well.

I'm a bit dubious about the reported 400t. The beam looks a bit deeper than track gauge, but even assuming (say) 2m deep x 1m wide x 25m long, it would only weigh around 125 tonnes.