Suggestions on composite bridge modelling

[StefanoPasquini6790]

Hello everybody,

I write email to ask advice about the most appropriate and efficient modeling about a bridge that I am designing.

The bridge is composed of two lanes in each direction, separated in the middle by a truss. Each track is composed of three steel I-beams on which is provided a concrete slab cooperating with the metal structure.

Personally I would the web of steel beams with shell elements and flanges, upper and lower, with beam elements (PLAT) in order to have the possibility to exploit the function of optimization of Robot.

The problem is when I insert the concrete slab.

How do I evaluate the composite steel - concrete section?

How can I differentiate the elastic modulus of concrete actions for long-term and short-term ones?

Maybe I can make a spreadsheet with iterative API to manage the various aspects of the design of composite sections? If yes, how can I set it to deal with these issues?

Thank you in advance, Regards