There is a growing emphasis these days on on-site operations in the field of precasting, prestressing, and post-tensioning. Contractors and engineers who have had experience with on-site work report that it has some impressive advantages, and they mention such factors as greater flexibility, the greater ease of scheduling and elimination of job delays, improved control over quality and workmanship, lower construction and maintenance costs, and finally the opportunity to use members having longer spans than those which can be trucked to many job sites. A recent and important example of job fabrication in the Seattle area is an all-concrete warehouse for the storage of flour and grain products. The requirements of an odd-shaped site, the need for the minimum of interior columns to facilitate the maneuvering of fork trucks, and a tight construction schedule, all focused attention on the possibilities of using job-fabricated post-tensioned concrete beams having unusually long spans. The post-tensioning technique applied on the project consisted of pouring the forms in an upright position on the floor slab. Because of the trapezoidal shape of one half of the building, all beams were of different lengths, ranging from 51 to 58 feet. However, the same forms were used for all beams, with adjustments in linear dimensions being made on one end. After the ready mixed concrete was placed and had reached the desired strength of 5,000 psi, hydraulic jacks were attached to the tendons at the unanchored end. Tensioning up to 105,000 psi was applied to the bars which were then anchored in the stretched condition by use of special wedges. To fill the space between the tendons and their surrounding steel sleeves, grout was pumped into a small opening left for this purpose. When completed the 7 and one-half inch thick beams represented a extremely favorable cost when compared to the cost of steel or glued laminated wood.