Existing Masonry Parapet to new exterior wall

[carnahanad]

I have a project that was supposedly designed for a future 2nd story addition. Masonry bearing walls are used to support a precast roof (currently) with the intent to add a topping to the precast to make a floor and then we are to add new masonry walls and a new steel joist/deck roof. The existing bearing wall details show precast bearing on the masonry with dowels called out in the keyways and reinforcement shown below the precast. The detail also shows the majority of the parapet bearing on the precast with just a little room for where a continuous bar could exist. In none of the details or notes can we find information about reinforcement or grouting of the parapet. The parapet is 2ft tall. The new wall would sit on this parapet and we would need to transfer in-plane and out of plane wind shear values as well as the vertical load.

The options are to

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1. Demo the masonry and dowel back into the existing precast slab as required. I like this because it's back to mostly shear in the out of plane and some tension from the shear wall conditions. The bad news is the arch would like to avoid demoing the 2ft of brick in front of the parapet and I'm not sure how this could be done.

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2. Keep the parapet and figure out how to justify the reactions on the parapet cantilever wall are acceptable.

Any thoughts on the option 2 load transfer?

Thanks!