Thermal gadient for Plate and Beam element

I will like to know how can I assign a thermal gradient load to an assembly where girders are modeled as beam elements and the deck is modeled as a plate element. Please refer to attach model. 

I need to assign a thermal gradient load with 10 C at top of the concrete deck and 0 C at the bottom flange of the precast girder. I have already defined sections for resultant forces for your convenience. 

Thanks

You can do it as shown below.

Please refer to the attached model.

Regards,

DK Lee