Can you have two layers of reinforcement in 150mm precast wall?

[Gile_]

The client wants to change the 200mmx1000mm 'gravity' blade column to 150mm thick wall and don't mind increase the length to, say 2m, if needed. Due to the ductility requirement I still need to design these 150mm walls as columns.
So do you put two layers of reinforcement in OR,
if two layers of reinforcement is hard to arrangement due to the limited space, do you put one layer only and design as columns anyway and check the curvature?

 

[r13]

Wall/column thickness for two layer steel ≥ 2*Concrete clear cover + Min. clear bar spacing + 2*d[sub]b[/sub] (main reinf) + 2*d[sub]b[/sub] (transeverse reinf).

 

[hokie66]

Aside from the structural issues of using such a thin wall/column, two layers of reinforcement can be incorporated in precast 150 thick elements, cast horizontally. It is a slab, then you lift it.

 

[Enhineyero]

This is the tricky part. Unless the whole structure model is analysed with no ductility assumed, the tensile stress cannot be used to verify this clause. But then you have to adjust your model to non ductile, which will fail for sure so you end up going back to the ductile design, which means this clause doesn't meet the condition.

Sounds like a multi-storey building project to me. Not sure if you are familiar why those clauses were placed there, but the short of it is basically for situations like this (i.e. thin singly reinforced wall on multi-storey building). If you ask whats the purpose of it, then the answer is its part of the lessons learned in the Christchurch Earthquake. A lot of the buildings that failed (and exhibited non-ductile behaviour) during that event have exactly this: 100/150mm thick walls with a single layer of mesh reinforcement.