interpretation of IBC2000 section 1614.1.1

[prsconsultant]

My question is how to interpret IBC2000 section 1614.1.1 item 2 additions to existing buildings, which states that:

"The addition does not increase the seismic forces in any structural element of the existing structure by more than 5% ....".

Question: When we are checking the existing structural elements, is this 5% rule based on the force demand from the original code of design or the current code.

Also when the code says "unless the element has the capacity to resist the increased forces determined in accordance with Sections 1613 through 1622" -

Question: Does this mean the existing elements have to satisfy the detailing requirements also?

Thanks in advance for your help.

 

[SperlingPE]

Question 1: Current code.
Question 2: Detailing requirements only if the element has to be modified because of the new load.