Accurately determining each strand's unstrained cable length (UCL) for a suspension bridge is critical for ensuring structural safety and minimizing construction errors. The traditional methods often overlook the distribution of strands, particularly the spatial curves within splay saddles and anchor spans, which may lead to significant deviations in strand length. Hence, a novel calculation method for determining the individual strands' UCLs was established, specifically focusing on the spatial configurations within the splay saddle and the anchor span. A simplified formula was developed to estimate the elevation sensitivity coefficient at mid-span, facilitating rapid adjustment to strand configurations during construction. The results demonstrate that the proposed approach achieves a maximum error of only 0.03‰ of the total strand length when compared to measured data, with most discrepancies occurring in the anchor span due to variations in anchoring positions. Additionally, it is observed that the longest strand exceeded the shortest by 0.812 m, with upper strands in the section being longer than the central strand, leading to a symmetrical UCL distribution in the main and side spans. Still, the distributed anchoring positions impact UCL distribution symmetry significantly in anchor spans. Moreover, the sensitivity of mid-span elevation to UCL increases with the span length. This study offers a valuable approach to improving the precision of the cable strand configuration, contributing to better construction control. • New analytical method for determining unstrained cable length (UCL) of suspension bridge strands. • Simplified formula developed for estimating elevation sensitivity coefficient at mid-span. • Achieved maximum error of 0.03‰ in strand length compared to measured data, mostly in anchor span. • Sensitivity of mid-span elevation to UCL increases with span length. • Proposed method outperforms catenary and parabolic theories, improving precision and construction control.
Zhang et al. (Wed,) studied this question.