Modeling box grider bridges using shells

Hi,
I was wondering if anyone knew how to model a box girder bridge using shell elements. My bridge has a variable cross section.

Also, what would be the best way to model a box girder bridge? Is it better to mix shell and frame elements?

thanks,
bojun

 

[zliazmei]

Bojun,
About modeling box girder bridges, you can find "Bridge Engineering handbook" by Duan and Chen.
Zmei