Watched this process on the new building opposite, 100 + bored then rebarred, then poured piles, with the rising structural pillars then cast in cardboard sleeves around the next rebar cage attached to the piles rebar, some have 10 x 20 foot sections to full height with floors cast onto the pile/pillar rebar just below the next section. Several below ground 'curtain' walls were done with one set done and cast, then the spaces filled with a following set cut into the periphery of the adjacent piles once dry.