连续梁拱组合体系桥梁关键参数分析及其优化
Analysis and Optimization of Key Parameters for Continuous Beam Arch Composite System Bridges

为了研究连续梁拱组合体系关键设计参数对结构受力行为的影响规律，得出各参数的合理取值范围与最佳设计参数组合，为该类结构体系的设计和工程应用提供参考。本文依托背景工程，利用Midas/Civil有限元程序建立了结构的数值模型，分析筛选出拱梁刚度比、吊杆间距、无索区长度和矢跨比等体现桥型设计特点的设计参数，以上述参数为研究变量，得到结构在荷载作用下各关键截面应力及变形变化规律，提出合理的参数取值范围。结果表明：拱梁刚度比的变化对结构受力影响尤为显著，主梁压应力随着拱梁刚度比的减小其应力储备也在减小，合理的拱梁刚度比取1/26.1~1/58.1；随着吊杆间距的增大，主梁下挠逐渐增大，拱肋与之相反，拱肋分配到的荷载逐渐减小，合理的吊杆间距为8 m~16 m；无索区长度和矢跨比的改变主要影响拱肋的受力行为，合理的无索区长度取37 m~53 m，矢跨比取1/7~1/6。结合结构受力特点进行分析，连续刚构梁拱组合体系桥在拱梁刚度比为1/41.76，吊杆间距为10.5 m，无索区长度为37.75 m，矢跨比为1/6.7时的搭配组合下为最优组合。
In order to study the influence of key design parameters of continuous beam arch composite system on the structural stress behavior, obtain the reasonable range of each parameter and the optimal design parameter combination, and provide reference for the design and engineering application of this type of structural system. This paper based on background engineering; a numerical model of the structure was established using the Midas/Civil finite element program. Design parameters reflecting the characteristics of bridge design, such as arch beam stiffness ratio, suspension rod spacing, cable free zone length, and rise span ratio, were analyzed and selected. The above parameters were used as research variables to obtain the stress and deformation changes of each key section of the structure under load, and a reasonable range of parameter values was proposed. The result shows that the change in the stiffness ratio of the arch beam has a particularly significant impact on the structural stress. As the stiffness ratio of the arch beam decreases, the stress reserve of the main beam also decreases. The reasonable stiffness ratio of the arch beam is 1/26.1~1/58.1; as the distance between the suspension rods increases, the downward deflection of the main beam gradually increases, while the opposite is true for the arch ribs. The load distributed by the arch ribs gradually decreases, and the reasonable distance between the suspension rods is 8~16 m; The changes in the length of the cable free zone and the rise span ratio mainly affect the mechanical behavior of the arch ribs. The reasonable length of the cable free zone is 37 m~53 m, and the rise span ratio is 1/7~1/6. Based on the analysis of the structural stress characteristics, the continuous rigid frame beam arch combination system bridge is the optimal combination when the arch beam stiffness ratio is 1/41.76, the suspension rod spacing is 10.5 m, the length of the cable free zone is 37.75 m, and the rise span ratio is 1/6.7.