I am trying to model a maintenance bulkhead structure consisting of several steel beam members, upstream and downstream girders, connected by diagonal bracing members (the structure resembles a truss laid horizontal on its side). The model also utilizes plate members connected to the upstream girder beams to model the skinplate of the bulkhead.
My question pertains to the use of beam offsets. Is it correct to assume that the main function of offsetting the beams is to achieve the appropriate member lengths (since STAAD connects members at their centerlines, which is not where the members are physically connected), and offsetting does not directly effect the way load is transferred between members, since STAAD still sees them as connected at the nodes.
Specifically, in my model, the skin plate members, when viewed in 3D rendering, appear attached to the centerline of the webs between the upper and lower girders. In reality, the skinplate will be welded to the outside of the flanges of these girders. Since in my model the loading is hydrostatic load applied to the plates, does the location of the plates matter? I.e., will offsetting the girders so that the flanges line up with the skinplates effect the way the structure is loaded?
Also, the bracing members between the upstream and downstream girders are modeled as being connected to the centerlines of the webs of the girders. In reality, these members will be welded to the outside of the flanges of these girders. Am I correct to assume, since these are compression members, that it is conservative to not use offsets?
Thanks in advance for any help,