中朝鸭绿江界河公路大桥耐久性技术研究

Study of Durability Enhancing Techniques for Yalu Boundary River Highway Bridge Connecting China and DPR Korea

中朝鸭绿江界河公路大桥为主跨636 m的双塔双索面钢箱梁斜拉桥,桥址处气候严寒,气象条件复杂。为解决桥梁耐久性问题,通过理论与试验相结合的方法,进行高流态耐海水侵蚀的抗冻性高性能混凝土配合比设计、-10^-5℃低温焊接技术可行性、斜拉索外置式阻尼减振技术等研究。结果表明:优选确定的混凝土的抗压强度、收缩特性、抗渗特性和抗冻融特性均最优,满足设计要求;按实桥焊接工艺成型试板,实测试板接头的抗拉强度,焊缝金属的屈服强度、抗拉强度、断后伸长率均满足要求,验证了在-10^-5℃低温焊接的可行性,并根据试验结果制定钢箱梁保温、预热及其它低温焊接质量控制措施;开发的综合电涡流阻尼及摩擦阻尼的斜拉索摆式杠杆质量减振器具有良好的减振效果和温度稳定性。该桥采用上述技术可确保其具有良好的耐久性。

The Yalu Boundary River Highway Bridge is a two-pylon steel box girder cable-stayed bridge with a main span of 636 m .The bridge site is located where the climate is harsh in winter and the meteorological condition is complex ,creating challenges for the durability of the bridge .By the combined use of both the theoretical and experimental methods ,a number of studies were conducted ,including the mixing proportion design of the frost-resisting high performance concrete that has high flow state and is able to resist sea water erosion ,the feasibility of - 10 ~ - 5℃ low temperature welding techniques and the externally-installed vibration absorbers for stay ca-bles .The results of the study indicate that the chosen compressive strength ,shrinking behavior , impermeability and frost and thaw resistant performance of concrete all have superior indexes which meet the design requirements .The trial plates were made to take shape by the welding tech-niques applied to real bridges .The tensile strength in the welding joints of trial plates and the yielding strength ,tensile strength and the extension rate after break of the metals in the welding joints could meet the requirements .The feasigility of - 10 ~ - 5 ℃ low temperature welding is proved feasible .And according to the testing results ,the quality control measures for the steel box girder heat preservation ,preheating and other low temperature welding were determined . The pendulum leverage mass vibration dampers featuring the eddy current damping and friction damp -ing for stay cables have sound vibration damping effect and temperature stability .The application of the aforementioned techniques ensures that the bridge has sound durability .