Hello Team,
I have modeled one of the RCC building,in that model I have applied vertical earthquake as per IS 1893-2016,
the problem is that when analyze the model I achieved base shear in x and z direction but in y direction I achieved zero value,
as per IS 1893-2016 cl.6.4.6the value of base shear in Y direction is 2/3 of base shear in X and Y direction, so that value not achieved.
Can you please share the file here?
MODEL-R1.STD
THE BASE SHEAR (VB) FROM RESPONSE SPECTRUM IS LESS THAN THE BASE SHEAR (Vb) CALCULATED.
YES THAT WE UNDERSTOOD SO THAT WE HAVE TO SCALE UP OUR RESPONSE SPECTRUM BASE SHEAR OF X AND Z DIRECTION BUT MY QUESTION IS WHY MY BASE SHEAR VALUE SHOWN ZERO IN Y DIRECTION IN RESPONSE SPECTRUM CASE
Hello Akash,
In your model there are a lot of small cantilever portions which are participating in the initial modes. As the seismic mass excited for those modes are very very less, you are not seeing any such base shear value. By default STAAD shows 6 modes and those modes are not sufficient to capture the full response. In this case, you need to increase the number of modes using "CUT OFF MODE SHAPE" command available under miscellaneous analysis commands.
With Cut off mode shape 150 for this file i am getting below result.