摘要
瓮开高速开州湖特大桥为1100 m单跨钢桁梁悬索桥,钢桁梁采用缆索吊装系统由中跨跨中往桥塔方向对称整节段安装。为确保加劲梁在施工期间及成桥阶段线形和内力均满足要求,采用非线性分析软件BNLAS建立大桥施工全过程空间有限元模型进行施工控制计算。加劲梁安装过程中线形呈现先下凹再上拱的变化,梁段间均采用临时连接,上弦采用由耳板及销轴组成的铰接装置铰接,下弦断开。施工中主索鞍分9次顶推确保桥塔受力安全,成桥阶段塔偏小于1 cm。根据加劲梁线形及下弦开口量变化规律确定刚接时机,悬吊段刚接完成后加劲梁应力均小于材料容许值。根据大桥结构特点及施工方案,确定主动调整端梁姿态适应悬臂端加劲梁线形的合龙控制措施。对恒载、主缆弹性模量、温度、桥塔收缩徐变等对加劲梁成桥线形的影响进行敏感性分析,并采用实测值对计算模型进行修正。采用各项控制措施后,该桥加劲梁成桥线形平顺,跨中节点处最大误差为+17.8 cm,满足规范要求。
The Kaizhou Lake Bridge of Weng′an-Kaiyang Expressway is a suspension bridge with a single suspended span of 1100 m.The steel trusses forming the stiffening girder were symmetrically installed from the midspan of central span towards the two towers,segment by segment by using cableway cranes.The whole construction process of the bridge was numerically simulated in the non-linear analysis software BNLAS,to make sure that the alignment and internal forces of the stiffening girder at the construction stage and after completion could reach the required levels.The alignment of the stiffening girder in the construction process varied from a downwarping state to having a camber.The upper chords of already-installed trusses were temporarily connected via the hinged devices formed of lug plates and pins,while the lower chords were free of temporary connection.The saddles resting on the top of the towers were carefully pushed for nine times into position without compromising the load bearing security of the towers,and the offsets of the towers after completion of the bridge were less than 1 cm.The timing of rigid connection was determined in accordance with the alignment of the stiffening girder and the opening amount of the lower chords,as a result,the stress in the stiffening girder after the rigid connection of the steel trusses was less than the allowable value of material.Based on the structural characteristics of the bridge and construction scheme,it was determined to actively adjust the girder-end attitude to match with the alignments of the stiffening girder at cantilever tips.Multiple sensitive parameters associated with the alignment of stiffening girder after completion of the bridge were analyzed,including dead loads,elastic modulus of main cables,temperature,and shrinkage and creep of towers,and the numerical model was modified with measured data.After taking control measures,the alignment of the stiffening girder after completion of the bridge is smooth,with a maximum alignment error of+17.8 cm at the midspan nodes,which was within the required range.
作者
王海南
阙水杰
尹斌
WANG Hainan;QUE Shuijie;YIN Bin(China Railway Development and Investment Group Co.,Ltd.,Kunming 650599,China;China Railway Bridge&Tunnel Technologies Co.,Ltd.,Nanjing 210061,China)
出处
《世界桥梁》
北大核心
2023年第6期53-59,共7页
World Bridges
基金
中国中铁股份有限公司科技开发计划项目(2019-重点-04)。
关键词
悬索桥
加劲梁
铰接
主索鞍顶推
刚接时机
合龙
线形
施工控制
suspension bridge
stiffening girder
hinged connection
saddle pushing
rigid connection timing
closure
alignment
construction control
