Please refer to IEBC 2015 section 907.4.1 regarding existing structural elements resisting lateral loads:
"An engineering evaluation and analysis that establishes the structural adequacy of the altered structure shall be prepared by a registered design professional and submitted to the code official."
Do you interpret this section to mean that during a level 3 alteration the building's lateral system must be modernized, regardless of whether any lateral-resisting elements are affected by the alterations? This provision seems to eliminate the 10% allowance given in other sections of the code. Should the analysis include the ultimate loads from IBC 2015? This seems like a prohibitively costly provision
"An engineering evaluation and analysis that establishes the structural adequacy of the altered structure shall be prepared by a registered design professional and submitted to the code official."
Do you interpret this section to mean that during a level 3 alteration the building's lateral system must be modernized, regardless of whether any lateral-resisting elements are affected by the alterations? This provision seems to eliminate the 10% allowance given in other sections of the code. Should the analysis include the ultimate loads from IBC 2015? This seems like a prohibitively costly provision