Re: Abs split wye
An abs coupling sitting on the plate will also work as a riser clamp, we use them on under floors and 2nd floors, adds another pipe support at each termination and the couplings are cheap. Oh and they take up less space.
The weight of the 2" line on the wye branch probably caused the split. An expansion joint or a simple riser clamp secured to the line at the plate level of the immediate floor above would have prevented the crack.