The query is regarding Scale Factor vb/vB while performing Dynamic Analysis as per IS1893-2016. Do we have to manually enter scale factor or system uses it automatically? If the program calculates automatically then why does it report as a note?
The multiplying factor is calculated automatically if data for IS 1893(Part-1): 2016 Seismic definition is available along with the IS 1893(Part-1):2016 Response Spectrum load cases. If the Static base shear (VB) is grater than the base shear computed from Response Spectrum analysis(Vb), program takes care of it automatically. All the response quantities are multiplied by (Vb/VB) internally by the program. This follows the requirements of Clause 7.7.3 of IS 1893(Part-1) :2016. The note is printed in the output just to notify the users that we are calculating the same internally and the multiplying factor we are using internally to get the design results. This is for your information only and there is no step required from the users.