use of reinforced concrete boxes in bridges

[tecnocrat]

we are using R.C.C. BOXES AS bridge culvert extensively in railway.we have used them up to 10 m of span.i have doubts
whether
1)r.c.c. boxes should be used for such large spans as their durability may be doubtful.
2)up to what limit of span these boxes can be used without any design/durability problem.
3)does vibration of railway traffic affects r.c.c boxes in any way.

 

[ishvaaag]

Here in Spain I have myself seen design for culverts 8 m free span or bigger in highways of the seventies and are standing 25+ years of service. Significant fill atop is extant, and thicknesses look quite awesome for the unaccustomed eye (on the 1 m thick both slab and walls).

Some flood no doubt already has been, surely not full section. The boxes in this case looked intact, and one feels the embankments will be gone before than the culvert. Maybe for flimsier thicknesses, and scarce ballast/earth cover your concerns become more significant.

 

[IJR]

Thanx Tecnocrat for the subject.

I was about to pose one of the kind.

There is a stadium In Italy in which an RC box girder runs from one corner to the other with 2 end and a couple interior supports. The supports serve as stair towers. And the giant girder is a peripheral support for one giant wing.
Seems to be a work of a good engineering and architectural collaboration(Apparently Italy is about engineered architecture)

I love the statical standpoint and the stadium really looks statically neat.

I thought I could share my fascination on this great structural element. Sorry if this one sounds off-topic

regs
IJR