This Specification addresses requirements for drilled pier construction. Drilled piers are sometimes called drilled shafts, drilled caissons, drilled piers with bells, drilled shafts with bells, or bored piles. This Specification includes: excavation; the use of liners and casing; drilling slurry and concrete free-fall placement methods; testing; reinforcement fabrication and placement; concrete properties and placement; quality control and quality assurance; and acceptance. The successful installation and performance of a drilled pier is fundamentally dependent on the means and methods of construction along with the effects of the site-specific subsurface conditions.