Precast concrete slabs

[Anonymous]

Hi, 

I am doing my work on an insitu and precast concrete building. I have done the insitu building in ROBOT and have done the analysis as well. But I am stuck with my second building as to how to provide precast slabs. Please can anyone tell how can we model a precast slab in ROBOT.

Thanks 

Arya

[EduardoMeruvia]

Hi @Anonymous , 

Is there a specific analysis you are after? 

Otherwise, I see no reason why you can't just modelled it as what you done so far with cast-in situ.

The precast slab capacity should be calculated the same way you do cast-in situ.  The only difference that I can see is the additional load cases to consider i.e. cast lifting, transporting and lifting in to place. Another potential difference is if you are thinking to lift/transport/place your precast slab before it reaches its 28day strength. Then you need to adjust your design accordingly. 

[Anonymous]

Hi Sir, 

Thank you very much for your fast reply. I am actually not behind any specific methods of analysis. Its basically a comparison of insitu and precast concrete building where in I have to give loads and analyze both the buildings get their values and compare. I just wanted to clarify if there is like any specific slabs for precast in ROBOT like what we have in Tekla structural analysis. Or will the loading condition only change and rest procedures are thw same...? 

Thank you 

Arya 

[EduardoMeruvia]

The procedure would stay the same as far as I can tell, with the exception of those additional load cases as mentioned.

What is the difference in Tekla between pre-cast and cast in situ that you have to do for analysis? 

[Anonymous]

Hi,

In Tekla, there are specific precast members for beam and slab. 

[EduardoMeruvia]

What do these specific precast members from beams and slab differ interms of design?

[Anonymous]

I am not very sure of how precast members from beams and slab differ interms of design. I have seen that there are specific precast sections.

And regarding the additional loads on precast slabs, where can we get that loads from..?

Thanks

[EduardoMeruvia]

My take on the precast specific tools in Tekla is that they are for "labelling" purposes only. I don't suspect they actually have any meaning in terms of concrete capacity design for strength and service. 

The additional loads mentioned, they should be based on your country Code/Standard, e.g. Eurocode 2 (Section 10) if you are in Europe, AS 3850 if you are in Australia, etc.