The invention is a reinforcement unit for reinforcing a footing element by laying a pile foundation with a foundation pile with at least one through-going longitudinal cavity and a method for placing the foundation pile and reinforcing a footing element with the reinforcement unit. The reinforcement unit includes at least one shaped and articulated reinforcement member that is pivotably connected to a centrally arranged, annular element, so that the reinforcement unit has a folded mounting position and an extended position of use, and is connected to the foundation pile by one or more tension members.