I think you have to tell me more specific what you're looking for and answer my questions otherwise it's sort of difficult to help you.
1. Are you modelling cast-in-place concrete beams?
2. Why would you like to split those two beams?
3. What's your opinion about how those 4 beams join together in reality?
If you are going to split those beams you can use Modify->Split elements. Then pull the ends away from the intersection by dragging the blue dot. After that you have 4 separate beams. Join the 4 beams by dragging the blue dot one by one towards the intersection.You'll notice that there's a disturbing autojoin feature when dragging the last beam end. You can play around with the blue dots to find a result that suits you. Regards, Anders
