Due to the deformation between the pylon and the girder caused by single tension of cables, the previously tensioned steel strands have stress relaxation, resulting in the actual cable forces being less than the design cable forces. To compensate the stress loss caused by the single tension of cables, this paper aims to present a practical compensation algorithm of stress relaxation during the construction period.
From the perspective of the essential cause of the stress relaxation, finite element analysis is used to solve the tension control force of each steel strand after a rigorous theoretical formula derivation.
The deformation and tension control force of each steel strand decrease with the advance of the tension sequence, and the decline rate drops gradually. However, the calculated force values of the steel strand are in good agreement with the measured value as the cable length decreases.
The previous rough calculation methods for the tension force of steel strands cannot meet the accuracy, and the accurate calculation methods often include the solution of nonlinear equations, which complicate the calculating process. Otherwise, there are few studies on the compensation of stress loss by calculating the deformation of the steel strand during the tension process. So, it developed an accurate and efficient algorithm to determine the tension control forces.
