钢管混凝土系杆拱桥拱脚一致多尺度建模及分析

Concurrent multi-scale modeling and analysis of springing joint for CFST tied-arch bridge

针对传统精细化模型在分析钢管混凝土系杆拱桥拱脚时,存在局部边界模拟困难、分析精度难以保证等问题,基于结构一致多尺度建模理论,提出将全桥模型通过合理的连接方式统一到拱脚精细化模型上的思路,建立了适用于钢管混凝土系杆拱桥拱脚受力性能分析的一致多尺度建模方法,并对一座计算跨径96 m、矢跨比为1/5的下承式钢管混凝土系杆拱桥的拱脚受力性能和安全性进行了研究.研究结果表明:一致多尺度建模在极大地减小了计算量的同时,还可以准确模拟钢管混凝土系杆拱桥等复杂结构的局部边界条件,并预测拱脚构造的力学行为;钢管混凝土系杆拱桥拱脚结构总体受力合理,但在预应力钢筋锚固区及支座附近区域存在较为明显的应力集中现象.

To solve the difficulties of local boundary condition simulation and analytical precision guarantee for analyzing the springing joint of CFST tied-arch bridge by traditional elaborate finite element model,a new modeling idea of introducing global scale model to local accurate finite element model of springing joint with reasonable connections was proposed based on the multi-scale modeling theory. The multi-scale modeling method was also developed to investigate the behaviors of springing joint for CFST tied-arch bridge. The mechanical behavior and the safety of springing region of a CFST tied-arch bridge with computed span of 96 m and rise-span ratio of 1 /5 were investigated. The results show that the concurrent multi-scale modeling method can not only model the local boundary conditions of CFST tiedarch bridge,but also can predict the mechanical behavior of springing joint with significantly reduced computation cost. The stress in springing joint is reasonable,while the stress concentration in prestressed anchorage zone and near supports is obvious.