Open stirrups in the prestressed precast concrete girder

[KimWT]

Hi!

This 40ft long girder was designed to support 60ft long precast double tees at both sides in the parking garage.
Recently, I saw some outside engineers use open stirrups in the girder design;
personally, I have never seen this reinforcement design before.

I am curious what other engineers think about this reinforcement design.

Thanks!

 

[KimWT]

According to MnDOT research paper, I can add one more variable related with this issue.
What happens if the bottom portion is removed (open stirrup)?
How does it affect the flexural strength or crack control?

I am looking forward to more inputs.

Thanks!