A prescribed prestressing process is employed to construct precast concrete beams and girders. The process is utilized where an early concrete strength is too low for transfer of the full pre-tensioning force on a daily schedule to avert an otherwise serious and costly production delay. The process described provides the producer a reliable way of making beams and girders that are prestressed to take advantage of the higher concrete strength characteristics. The consequent economic advantage of higher structural capacity beams and girders is thereby realized. Additionally, beam or girder camber is controlled by the process, fostering production of a superior quality product.