Please help with the modeling of a box girder. Attached is the image.
I have modeled the box considered as beam elements with width 1.5m and depth as thickness. The overhanging portion of W10x49 is modeled as dummy. I have considered the sections W10x49 and W12x40 as point loads . Please suggest if this kind of modeling is correct and how to model the gusset plate/WT6x20 bracings between them.
From the way you have described, it seems like you are interested in analyzing the box girder only. However looking at the way the rest of the structure is, I think it may be better for you to model the members on top instead of just considering the loads from those because at the end of the day the box girder and the pipe supporting structure on top are interconnected and so it is the combined stiffness of the structure that is going to come into play to resist the load. It will be difficult to do a proper stiffness analysis if you consider the parts in isolation. The braces would need to be modeled using beam elements but I would leave out the gussets from the analysis model.
I have modeled the box elements as plate. I am not aware how to place the beams above. Instead i used their weights for load transfer. But as you rightly pointed out, they are interconnected. Kindly suggest how do i model the whole structure
I assume you have used a mesh of plates to model each of the faces of the box girder. To connect the beams to the box girder, you just need to ensure that these beams connect to the nodes of the plate mesh. The horizontal W10X49 lying immediately above the box girder can be modeled by defining beam segments joining the nodes of plate mesh at top of the box girder with projections on each side.
So basically between two end nodes of the box girder, ill have plate elements as well as beam element. Is that correct?
Correct