gusset plate

huangyhg

gusset plate.....
i have encountered designs of steel trusses that doesn't introduce gusset plate at the joint. web members are directly welded to the top chord or the bottom chord, is it okay to do this? i wanna know what really is the purpose of the gusset plates in a steel truss..thank u guys in advance....
yes it is ok for direct point to point connections. the gusset plate is to facilitate different types of connections that can be easier to erect and generally less expensive (bolted connections etc) as opposed to fully welded connections.  
as willisv said, it is an erectability choice.
welded joints are a reasonable option if the truss is still buildable.
normally with fully welded trusses you will still need to divide the truss into sections with bolted splices between for transportation and erection.
you really need to try and learn as much as you can about how these things are built, because construction method often governs design and the greatest savings are often those that make construction simpler.
another possible reason for the gussets is shear in the chords, which means you're likely to see them primarily towards the ends of the truss. chances are you will never really have all the forces coincident at a joint, so the chords need to be designed for a shear equal to the vertical component of the web forces.
a lot depends on the members used to build the truss.  for example, trusses with tee sections for the chords and angles for the webs can be fabricated without gussets, except where insufficient depth of the tee web requires a gusset.  and trusses are often made with closed sections, which can often be designed without gussets, at least in the lightly loaded joints.  on the other hand, if wide flange sections are used for the chords, gussets are almost always necessary.