Enhanced seismic and structural response of cable-stayed bridges with micro-cables

Cable-stayed bridges (CSBs) are favored for long spans, but their performance and cost are dominated by the cable system. Conventional fan, semi-fan, and harp layouts often require thick cables, leading to high fabrication, maintenance, and replacement expenses. This study introduces a novel “Micro-cables” arrangement, a hybrid fan-harp system designed to overcome these challenges. The configuration’s efficiency is evaluated through comprehensive numerical analysis of CSB models featuring five different pylon shapes and spans ranging from 50 m to 310 m. Using nonlinear static and spectral-based seismic analyses, the study compares the proposed system to traditional layouts. The results confirm significant performance enhancements. Quantitatively, the Micro-cables layout reduces pylon head displacement by up to 32% under dead load and 27% under traffic load compared to the harp configuration. Furthermore, individual cable axial forces are decreased by approximately 68% (distributed across the denser network of 360 micro-cables), and pylon base moments are lowered by 22–35%, depending on the pylon geometry. These structural improvements reduce seismic structural demands and suggest a potential for optimizing material usage, particularly in the cable system. While comprehensive lifecycle cost and constructability analyses are required for full validation, the structural improvements establish the Micro-cables system as a promising alternative worthy of further investigation.