Development and Performance Experiment of Iso-tensioning System using Electrical Resistance Loadcell

Because MS(Multi-Strand) cables consist of many strands, a jacking force is applied to each strand one by one for cable construction. All strands should have an equal tensile force when the last one is wedged. This is the core technology for MS iso-tensioning. In this study, a new MS cable iso-tensioning system was developed for controlling and jacking the high-strength strands, with an ultimate tensile strength of 2,200MPa, for a stay cable ofextra-dosed/cable-stayed bridges. The newly developed iso-tensioning system consists of electrical resistance load cells, hydraulic jacking devices, hydraulic pumps, and integrated controllers. Moreover, it is embedded with an algorithm that can control and predict the variations in tensile forces of the Master and Slave strands in real time.Actual experiments were carried out to verify the function and performance of the newly developed system. This system was applied successfully to the stay cable construction of 2nd Tae-in extra-dosed bridge in Gwangyang.