The main bridge of the Guansheng Qujiang River Bridge in Guang'an is a halfthrough concrete-filled steel tube (CFST) stiff skeleton arch bridge with the main span of 320 m.The stiff skeleton of the bridge was constructed,using the fastening stay method and in the construction,the fastening stays were tensioned in place in one time.In view of the limitations of the 2 calculation methods of the forward analysis and reverse analysis for the stay forces and to accurately calculate the stay forces and the pre-raising amounts of the arch rib segments in the installation and make the completed arch geometric shape approximate the theoretic geometric shape,the adjustment method of the optimal stay forces based on the control target of the completed arch geometric shape was proposed.The MIDAS Civil 2015 was used to set up the finite element model for the whole bridge at the hoisting and installation stages of the arch rib segments,the influences of the tangent displacement on the follow-up construction stages were considered and by controlling the geometric shape mainly and the stay forces subsidiarily,the geometric shape,fastening stay forces,backstay forces and the chord stresses of the bridge were analyzed and the analysis was compared to the measured values.The results show that the measured values of the geometric shape,fastening stay forces,backstay forces and the chord stresses are highly accordant with the theoretic values,the geometric shape and structural stresses of the main arch can satisfy the relevant requirements in the design and codes,proving that the adjustment method as mentioned is feasible and effective.%广安官盛渠江大桥主桥为主跨320 m的中承式钢管混凝土劲性骨架拱桥,劲性骨架采用斜拉扣挂法施工,施工过程中扣索一次张拉到位.针对正装分析法和倒退分析法2种索力计算方法的局限性,为了精确计算扣索索力及节段安装预抬标高,使成拱线形接近理论线形,提出以成拱线形为控制目标的优化索力调整方法,利用MIDAS Civil 2015建立吊装阶段的全桥有限元模型,考虑切线位移对之后施工阶段的影响,以线形控制为主、索力控制为辅,分析该桥的线形、扣索和尾索索力、弦杆应力,并与实测值对比.结果表明:大桥的线形、扣索和尾索索力、弦杆应力的实测值与理论值符合度非常高,主拱线形及结构应力满足设计及规范要求.说明该优化索力调整方法是可行有效的.
展开▼
