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Cantilever Beam-Slab Design

Cantilever Beam-Slab Design

Cantilever Beam-Slab Design

I have a square slab design layout where there is a grillage of beams with significant cantilevers in both directions (refer sketch - the slab outline is red, the beams yellow and the column supports orange).

I want to analysis/design the slab with RAPT using an idealised frame method. My plan of attack is to analyse the edge beam using the triangular load distribution shown in blue with supports at the location of the internal beams. I will then analyse the internal beams using the green load distribution and applying the support reactions from the edge beams at the cantilever ends.

I would love some feedback on the suitability of this approach and whether RAPT can apply these load patterns automatically or if I will need to enter the loads manually.

RE: Cantilever Beam-Slab Design


if this is supposed to be a RAPT support question, you should contact me by email!

The load patterns you have suggested are logical. You would need to define the load pattern manually for each of the 2 beams you have to define to do this floor..

Make sure when you look at deflections, you determine the corner deflection as the sum of the main beam cantilever deflection plus the edge beam cantilever deflection. With cantilever length = back span length, it will be interesting to see if you can make it work with the hogging in the back span. Not even PT can take out the effect of the hogging on rotation at the support and cantilever deflection!

Referring back to an earlier post about Robustness, it would be interesting to see how you could get this one to work. I would say impossible!

RE: Cantilever Beam-Slab Design

What is the scale? Looks like the cantilevers and backspans are equal, but are they 2000, 4000, 8000?

RE: Cantilever Beam-Slab Design

Thanks for the replies.

Although I do appreciate the advice on the use of RAPT it was more a design philosophy question on the use of the idealised frame method - and so I was to hoping to get answers from the general community.

My sketch is simplified. In reality the central span is 10m and the cantilevers are 4m. Also, at each beam intersection there are 4 closely spaced supports rather than just one as a showed in my sketch.

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