基于结构性能及经济指标的超大跨径缆索承重桥方案优选OA

Cable-stayed bridges,suspension bridges,and hybrid cable-stayed suspension bridges are the main-stream bridge schemes for achieving kilometer-scale crossing.To explore the adaptability of these three bridge schemes across different span ranges,this study designed several cable-supported bridge models with main spans ranging from 1 100 to 2 300 m by referring to the technical parameters of similar bridges.The static and dynamic performance and economic indicators of the structures were calculated and analyzed,and the influ-ence of the main cable sag-to-span ratio on the structural performance of the hybrid cable-stayed suspension bridge was deeply discussed.The research shows that the hybrid cable-stayed suspension bridge integrates the mechanical characteristics of cable-stayed bridges and suspension bridges,and can adjust the load-bearing ratio of the cable-stayed subsystem and the suspension subsystem by modifying the main cable sag-to-span ratio.Within the 1 100-2 300 m span range,hybrid cable-stayed suspension bridges have superior comprehensive performance compared with the other two schemes.As the span increases,the load-bearing efficiency of the suspension subsystem improves,and the optimal main cable sag-to-span ratio of the hybrid cable-stayed sus-pension bridge gradually decreases to 1/9,which is consistent with the commonly used value of suspension bridges.The temperature effect of the hybrid cable-stayed suspension bridge is relatively significant,which is mainly caused by the secondary internal forces generated by deformation incompatibility,and should be paid attention to during the design process.Based on the research background of this paper,it can be inferred that suspension bridges are more suitable for spans above 2 300 m,while for spans above 1 100 m,cable-stayed bridges have weak competitiveness due to technical challenges such as ultra-high pylons,ultra-long stay cables,and ultra-large cantilever girders.