Expansion in SDC E

[WiSEiwish]

I am going to be working on an expansion to an existing warehouse that is located in Seismic Design Category E. The building was designed in 1978 thus there is a very distinct possibility that the detailing does not meet current code. The main seismic load resisting system is precast shear walls which wrap around all four sides of the warehouse.
Of course, since the warehouse is to be expanded a certain amount of mobility is expected going from the existing structure to the expansion. The architect has accounted for this by proposing openings in the existing wall. This is of concern structurally for a few reasons.
1. The rigidity of the current wall is compromised.
2. The compromised wall will now support lateral loading from the expansion.
3. There is an opening in the wall that needs to be designed for with regards to flexure.
There is a question that I have with regards to a building of this nature. Since a portion of the seismic load resisting system for the existing building is compromised, what does that mean with regards to the analysis of the existing building as a whole. Would I need to make sure that the whole of the existing building meets code, or would I have to simply check the wall for the structural issues mentioned above? Where would I go to find out how to properly approach this?

 

[UcfSE]

I would look for a building code intended for existing buildings. In the US, that's the IEBC. That code would addess your questions if you're in the US. You may have a different one applicable in your location.