Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A method of constructing pre-tested concrete pilings and pile caps particularly for use in supporting structures, such as transmission line towers that are subjected to large overturning moments. One or more pile holes are bored, a small diameter sheathing containing one or more steel tendons is inserted and a concrete mixture is poured in the pile hole exterior of the tendon sheathing with the tendons anchored in the bottom of the pile. When the concrete has obtained sufficient strength, the tendon is stressed, thereby testing the tension-carrying capacity of the pile and its surrounding foundation soil. A concrete pile cap is thereafter joined to the pile, the tendons are again stressed and anchored to the pile cap and the tendon sheathing is filled with concrete grout to form a solid post-tensioned foundation that has been pre-tested at a force in excess of its design load.