how can we model B16.9 Buttwelded tee

Read the User Guide.

durgaprasad,

The tee in piping stress is usually modeled by designating 'SIF & Tees' for the node of the intersection of branch to run, then selecting '3 - welding' to get the appropriate SIF.

If you are attempting to model a flanged tee for the tee and flange dimensions, then you will need to get the correct dimensions for the tee and flanges per pipe size (ASME B16.9 and ASME B16.5 ) to construct the flanged tee.

thank you

if i want to model tee according to b16.9, whether i have to give sif or which one i have to select from list

As per Richard, Just click SIF and select 3-Welding, Caesar will calculate its sif.

how caesar will know whether tee was acc. to b16.9 or it was branch connected pipe without any informtion from our side?
what about option 7-welding?

There is a "configuration directive" that you can set to tell CAESAR II that your tees meet B16.9.