stirrup design using boxcar program

[oengineer]

I am designing a reinforced concrete box culvert using the BOXCAR 3.1 program and due to the fill height range i am coming up with stirrups. Does anyone know how to adjust BOXCAR 3.1 to increase the circumferential reinforcement steel areas and eliminate the stirrups?

 

[larsacious]

Perhaps you can make the top slab thicker to avoid the stirrups. Please elaborate on the fill height, design code, slab thickness, concrete strength, etc.

 

[JedClampett]

A lot of box culverts have fillets at the connected ends. These allow you to move the critical shear plane over even further.
Check your DOT standard details.