Span Information & Effective width

Question:

MIDAS tech,

1. When are the composite bridge > span information and > effective width used in MIDAS modeling? I don’t think I’ve ever used these previously and want to make sure that I haven’t overlooked these two windows.
Figure 1: span information for composite bridge
Figure 2: effective width of composite bridge

2. If I have a post tensioned box bridge that is along a curve and it is post tensioned longitudinally (in the boxes) and transversely (in the deck), what might be the best way to model this structure for both elements having post tension? Use beam elements for box girders in longitudinal direction and use beam elements for deck in the transverse direction? Will this be composite if I model this as so?

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Answer:Dear Mr. User,

1) Span information, comes in to picture for design consideration , effective width definition and reinforcement for tapered sections.
And effective width is used, when shear lag effect has to be considered, i.e to consider a reduced slab/flange contribution for resisting forces.

2) Only the longitudinal elements be composite. For transverse elements , prestressing, this would not be composite but just on dummy cross beams.