composite bridge model with steel box girder

[Neal76]

I'm trying to design a composite bridge with steel box girders under a concrete slab. However, SAP2000 does not have this option in the bridge modelling setup, and I'm having no success creating my own model using the girder design option. Basically, I've designed my box girder section, but the program does not allow me to introduce it for the deck design. Does anybody have advice?

 

[jorton]

I've run into a similar problem. The bridge module can only be used to apply bridge loadings in this situation. CSI said future versions of the Bridge Module will accommodate steel box girders. I manually modeled a steel box girder using shell elements for both the box and the deck. I connected the two using links of appropriate stiffness. It wasn't too difficult. The bridge module will only apply bridge loads to straight frame elements or to the "bridge elements" created by the bridge module. To use the bridge loadings I placed dummy frame elements (zero stiffness) along the concrete deck. The dummy elements will pick up the bridge loadings and distribute them to the deck and then to the box. Please note this might not work well if you are looking at load effects in the deck, but it should be close for the load effects in the box. Some careful considerations should be given as to where you place the dummy members and how you define the loading. Overall it just takes some trial and error.