Curved concrete walls (kind of Hyperbolic Parabaloid)

[NAFTALI-HAKOHEN]

Hi all,

Im designing a very large concrete wall for a public building (museum), that is curved in 2 directions:

Dimensions of the wall are around 35m length and 20 metres high (at the peak) , and the architect has modelled it in Rhino , so i have the exact dimensions (NURBS surface properties etc) for the wall.

The modelling and analysis of the wall is ok (with modern FEM software) , but im not sure how to PRESENT the structural diagrams of a 3D wall etc in inherently 2D CAD format?! to provide clear rebar diagrams etc for the contractor

Does anyone have experience or ideas for such elements?

Thanks

Naftali

 

[GeorgeTheCivilEngineer]

Most simple and highly rationalised reinforcement wins in my book.

A bit of extra steel is nothing compared to what the formwork costs will be... and allows some capacity headroom on what is a complex analysis.

 

[kostast88]

Is this wall supporting anything at all, or is it a free standing wall?

If it's supporting anything it looks unrealistic to me, with conventional rebar at least. Formwork would be fun! In situ concreting could be a serious danger for formwork failure.

You have to talk to a formwork specialist and see what they can offer. There are companies who specialize on that, if they tell you it's doable challenge them a bit untill you are 200% sure that it is. From a google search: Link

If it's supporting anything above, in my humble opinion forget this geometry, rationalize the design. Computer model says it's ok, means very little. Is it buildable? The essence of good engineering is to take in to account design & constructability of the proposal. If your numbers are great but none can build it, then there is no value in your design. And even if it is buildable, would you guarantee the purpose of this wall in the long term (durability,redundancy,etc)? Is it SAFE?

I don't know your geometry & loads, but I would just say an idea: this would better be adressed with Fiber-RC + reinforcement.

 

[kipfoot]

I think the key would be to describe the wall in a series of sections that show that a hyperbolic parabaloid is a system of straight lines. The reinforcing will be straight bars. The 'vertical' formwork studs will be straight pieces.

You may want to suggest a double layer of thin sheathing because the surface is curved.

 

[MotorCity]

Pretty neat. I see a couple of options. Consider constructing it as several discrete precast "strips". I assume the desired final appearance is one continuous surface. If so, you can probably grout the gaps between the precast strips and apply a rub finish to give the continuous, one piece appearance. For the reinforcing, you need to somehow define the geometry in a simple, non mathematical form. In other words, don't provide the detailer with some mathematical equation that gives the shape of the wall. Provide a series of dimensions and angles. Lastly, I would consider providing the rebar cut lengths, shapes, and quantities (i.e. detail the rebar yourself) and provide a bar placement drawing. That may be more work upfront for you but it will prevent alot of headaches later on.