Steel Stress Levels
DYWIDAG THREADBARS® may be stressed to the allowable limits of ACI 318. The maximum jacking stress (temporary) may not exceed 0.80 fpu, and the transfer stress (lock off) may not exceed 0.70 fpu. The final (working) prestress level depends on the specific application, installation procedure, stressing sequence, and the rigidity of the structural system.
In the absence of a detailed analysis of the structural system, 0.60 fpu may be used as approximation of the effective (working) prestress level. DYWIDAG THREADBARS® may be used individually or in multiples depending upon the magnitude of force requirements or upon drilling considerations. Actual loss calculations require structural design information not normally present on contract documents.