gantry truss - column base plate connection - pin or fi

huangyhg

gantry truss - column base plate connection - pin or fix ??
normally , i have pin connection for portal frame or similar structure. however, i check the gantry truss say 16-30m span with the column pinned base connection, a large deflection occur compared to fixed based.
it seem to me that i have to use column base fixed connection.

you will always get larger frame drifts with pinned bases compared to fixe bases.
what is your question?
it may help if you explain what you mean by "gantry truss" and better define your structural system.  the word gantry is used in several different ways in structures.
as streit wrote, what is your question?
i model a 16m long truss supported by columns of 6m high. pinned base columns give very high lateral deflection. i have to go for fixed based column to reduce to   
sure, it's ok.  why wouldn't it be?  just be sure to design the baseplates, anchor bolts, pedestal/pier (if applicable), and footing for the required moment.
tngv752
it's not a particularly high building, do you know why the lateral deflection is high?
maybe the columns are just too small?
there is nothing inherent in trussed rafters which would cause excessive deflection.
it's not economic to increase the   
where a column is nominally pinned to a foundation that is designed assuming that the base moment is zero, the stiffness of the base may be assumed to be equal to 20% of the column stiffness when calculating deflections under serviceablity loads. this may be done by introducing dummy   
parrot-
can you post a copy of that paper or give the author and a ballpark date?
s..eit,
the above post is based on guidence offered in the steel construction institute (berkshire u.k.)publication sci p252 titled 'design of single-span steel portal frames to bs 5950-1:2000'