大跨钢管混凝土拱桥混凝土自调载灌注方法

为改善大跨度钢管混凝土拱桥混凝土灌注期间结构受力和变形,基于拱肋应力和变形影响线,提出一种自调载灌注方法. 推导了拱圈加权弯矩能同混凝土龄期的理论公式,提出以分阶段成桥与一次成桥设计状态加权弯矩能差异最小为目标优化灌注间隔,避免已灌混凝土过早承载. 应用ANSYS自带的APDL语言,针对新龙门大桥开发了专门的灌注仿真程序,展开钢管混凝土拱桥分段灌注优化分析. 结果表明:所提出的自调载灌注法应用于钢管混凝土拱桥灌注施工是合理可行的,基于拱肋应力和变形影响线确定的灌注方案,可实现此类拱桥灌注过程中结构变形和应力的自控制；以分阶段成桥与一次成桥设计状态加权弯矩能差异极小为目标建立的优化方法,可合理确定大跨径钢管混凝土拱桥分段灌注的起灌时间. 相比临时扣索、水箱压重等调载方法,自调载灌注方法可减少施工辅助工艺,降低工程建设总造价.

Self-regulating loading pouring method of long span CFST arch bridge

To improve the stress and deformation of long span CFST arch bridge during concrete pouring, a self-regulating loading pouring method was proposed based on the stress and deformation influence line of arch rib. The theoretical formulas between weighted bending moment energy and concrete age of arch ring were deduced, and a method of optimizing perfusion interval was introduced to minimize the difference of weighted bending moment energy between staged and primary bridge constructions, which can avoid early bearing of filled concrete. A perfusion simulation program for New Longmen bridge was developed using the APDL of ANSYS, and the optimization analysis of segmental pouring for CFST arch bridge was performed. Results show that the proposed self-regulating loading pouring method could be applied to CFST arch bridge, and the self-control of deformation and stress during construction could be realized with the pouring scheme based on the stress and deformation influence line. The optimization method aiming at minimizing the difference of the weighted bending moment energy between staged and primary bridge constructions could reasonably determine the staged perfusion time for long span CFST arch bridge. Comparing with the methods such as temporary cable and water tank, the self-regulating loading pouring method could reduce auxiliary process and decrease the total cost of the construction.