How to design rc-structures with hollow core slabs.

[CivilTanju]

Hi all,

I want to design 4 storey structure comprised of RC Column-Beam where some part of floor slabs will be used as hollow core slabs (to serve as sound-isolator).

The system for such a stucture could be easily created even using template, but the problem arises when determining how should I model hollow core slab supporting beams. In my idea ,there aare the 2 alternatives that I need to follow.

1. Modeling structure conventinally (assigning the loads which regulations oblige us to do ) as if there won't be used hollow core slabs. But practically I'll use the hollow core slab.

Or

2.Leaving the openings where hollow core slabs will be placed and assigning the beams (with nibs) line loads equal to those which will hollow core slabs will apply.

I don't know which alternative represent the real situation. I'll try either of it.



Thanks In Advance.

 

[hokie66]

However you model your structural elements, just remember the hollow core slabs span one way only.

Do hollow core slabs really help with sound isolation?

 

[CivilTanju]

->.However you model your structural elements, just >remember the hollow core slabs span one way only.

yes you right but I thought it'd be better to ask a form before starting the design. Obvisously I try either of alternatives but the main idea behing posting in this thread was to query whether there any specifications in regulations about the design criteria.

->Do hollow core slabs really help with sound isolation?
Yes they are indeed. So even now on our on-going project we use it in moscow for cinema center sound insulaton.

best regards.

 

[hokie66]

I think it is the mass of the slab which determines the sound isolation properties. 200 hollow core slab, mass 280 kg/m2, STC 50. About same as 125 solid slab. 200 solid slab, STC 58.

 

[CivilTanju]

Along the mass of concrete the gaps are also governing the sound insulation property.

 

[hokie66]

Don't think so. Sounds like sales talk to me.

 

[csd72]

Design the beams as an upside down T beam. Cast beam first, then lay hollowcore, then pour topping slab. Legs of T will need to be designed as corbels.

Get some documentation from the manufacturer on that sound insulation they should be able to back up the sales claims with evidence.

 

[civilperson]

The hollow core slabs will load the supporting beams identically to a solid slab of equivalent weight. This is because the bearing ends of the hollow core will be grouted solid for the area adjacent to the beam. The topping and grout key can be reinforced to produce moment resistance at the supporting beams if desired, (use "L-bars from support into topping or grout).

 

[ppblog]

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