Erection strategy for main cable based on unstrained length of parallel wire strands

Abstract

This paper presents a construction scheme aimed at achieving one-time erection of strands through precise control of the unstrained length. The scheme entails correcting system errors through the initial strand erection and reducing the influence of random errors by improving manufacturing conditions and increasing field measurements. The key objective is to control cable erection using cable length. A reliability analysis program was developed to assess the accuracy of the main cable installation. A case study of an actual bridge was conducted to verify the feasibility of the scheme. First, an assessment of the distribution characteristics of the random variables was performed. Subsequently, a comparative analysis was performed to evaluate the reliability of the proposed scheme against conventional erection methods. Finally, the new method was validated by on-site installation of several strands. Results revealed that while the reliability of cable formation shape was comparable between the traditional method and the proposed scheme, the latter exhibited superior uniformity of internal force among cable strands after formation. In addition, the average value of the cable length correction for Nos. 2 to 15 strands closely aligns with that of the reference strand, suggesting that the systematic error correction determined by the reference strand exhibits relatively high accuracy. Furthermore, strands erected with cable length as the control objective effectively maintained sag errors within the range of [− 4 mm, 8 mm], demonstrating a high level of precision.