Seismic Separation Joint

[lacyma1]

I'm on the verge of starting a building addition in a Class C seismic zone. The existing building is quite large and complex and the as-built information
available is not complete. We have opted for separating the building addition from the existing building in order to eliminate the need to analyze the existing structure. In order to size the separation joint I'm looking at ASCE 7-16 Equation 12.12-2, but this still looks like I need to analyze the existing structure. Is there any way around this?

 

[phamENG]

I've only been in this situation once. As the fee was laughably small to begin with and the client (government) refused to pay for any additional work to analyze the existing structure, I looked at the building code in force at the time of construction and worked out the maximum allowable drift under that code. That's what I used. It was very conservative, but it worked and I didn't have to spend 3 days working for free to analyze a building for which I didn't have complete as-built information or even access to (it was 2000 miles away and a site visit was excluded, too).

 

[lacyma1]

Thanks! That makes a lot of sense!