We need to excavate below an existing RCP to install a new diversion box. The pipe is active and filled with water. The contractor is asking to support the RCP via option-1 and option-2 below. Typically, we completely support the pipe with straps and beams above in this case. We can do that here, but I wanted to see if this idea might have legs. The "free spanning pipe" will be no longer in use once the construction is completed. Option-1 seems to be a no go because of too little shear capacity of the lip of the pipe. The contractor's argument for option-1 is that these are notoriously hard to remove even when they are saw cut. I'm sure that is due to the axial force along the pipe and friction. Option-2 might work, but I'm worried about the beam reaction on the pipe that remains in place.
