![]() Your end drap may be affected accordingly, too. If you decided to use bonded tendons, you may want to check PT supplier's catalog for sizes of the anchorages and make sure they will fit in your beam's end section. In addition, you may want to use bonded tendons for this transfer girders because ACI 318 allows you to design PT force using much higher steel stresses. Even in etabs beam design, it considers the BM only. The axial tension force has to be catered together with bending moment. Recently, i noticed that in transfer beam design, its not just design the rebar based on bending. Typically, you can specify two stage stressing for a 4-floor girder. The construction is 95 completed and so far there is no any visible cracks. You may refer to the article Design of Deep Beam for the design of deep beams. Further, beams could be designed as simply supported beams or continuous beams. If you decided to use bonded tendons, it is better to stress one tendon to 100% at a time rather than stress 50 % of total force. Transfer beams are designed as deep beams and the design concept will be based on the type of loadings and the beam layout. If you design unbonded tendons, you can specify percentage of tendons to be stress at each stage. You best dead load balance is around 60% to 80% of dead load. The reason is not to apply too much post-tensioning force when you do not have that much dead load to balance. Like others said, you have to do "stage stressing" for this transfer beam. If you are using RAM or other programs, you may want to do a trial-and-error in order to get an ultimate design. If you ae using ADAPT PT, the program should adjust the PT force for you. Try a 36"x48" beam with a PT force of 2,500 kips. ![]()
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