Please share your idea, solution and recommendation on this kind of issue for pile reinforcement development shortage (image as attached). Thank you in advance.
I would recommend a mechanical splice on the bars. I would assume the cost of the mechanical splice would be cheaper than the labor to chip the concrete. Just my opinion, but both are acceptable options.
Mechanical splices would be easiest. Or drill and install extensions using adhesive. Lap the new bars according to ACI development lengths, and account for non-contact lap requirements when drilling holes.