25m span Floor

[aaronPTeng]

Anyone had any experience in design of a 25m clear floor span where form work is not possible? (note second direction is only 8m)
I am looking at either Precast T sections? or steel trusses in main direction with a precast flooring system in the second direction between the trusses?

Any ides appreciated!




"Structural Engineering is the Art of moulding materials we do not wholly understand into shapes we cannot precisely analyse, so as to withstand forces we cannot really assess, in such a way that the community at large has no reason to suspect the extent of our ignorance." Dr. Dykes, 1976

 

[hokie66]

You could use precast or steel for the main members. With the precast, then use bonded topping. With the steel, use a slab cast on form deck.

 

[JedClampett]

Precast double tees with a topping like hokie66 says.
They'll be about a meter deep.
But they'll be cheap.

 

[hokie66]

Jed, I think the economy of the various systems depends on where one is located. If I remember correctly, aaronPTeng is somewhere in Australia. Precast floor systems in buildings are uncommon in most areas of Australia.

 

[steellion]

There's no way to get it to span in the 8-m direction? You're going to need some deep sections to control deflection and vibration over a 25-m span.

 

[hokie66]

steellion,
Not to answer for the OP, but I think it is clear that if he can't provide temporary support, permanent support is out of the question.

 

[aaronPTeng]

hokie

Correct in AUS, I have designed a steel truss system as an option as the main supports (at 8m cts) with beams and form deck/king floor etc spanning between,

I am also exploring the precast double T sections also and speak to the precast company about $$

Regards

"Structural Engineering is the Art of moulding materials we do not wholly understand into shapes we cannot precisely analyse, so as to withstand forces we cannot really assess, in such a way that the community at large has no reason to suspect the extent of our ignorance." Dr. Dykes, 1976

 

[hokie66]

If you use double tees, consider carefully how any external wall/facade will be supported, as the tee flanges are generally not very thick.