Stuctural Capacity of Single Skin Masonry

[structuralex]

Adding another floor to a single storey house, approximately 40 years old.
External walls are double brick cavity.
Internal walls are single skin 110mm brick, 3000mm high.
I'll need these single skin brick walls to be loadbearing to support the joists/beams.
According to AS3700, the wall can support 47kN/m, but it just doesn't seem right to support a whole level on top of these brick walls?
And does anyone know the in-plane shear capacity of a single skin brickwall?

 

[PengStruct]

A couple things which you may have considered already:

1. What is existing soil capacity and what type and size are the footings?
2. A very small eccentricity in the loading of the thin wall will greatly reduce capacity. ACI 530 addresses this and unless you are supporting joists on both sides that are the same span and loading you will have eccentric loading. Or if the wall is slightly out plumb you can also have eccentricity.
3. What is a "double brick cavity"? Three wythes with a cavity between each wythe?