无背索曲塔曲梁斜拉桥施工优化

Construction Optimization of Curved-pylon and Curved-girder Cable-stayed Bridge without Back Stay

为优化无背索曲塔曲梁斜拉桥施工顺序,对桥梁施工进行全过程模拟,确保桥梁在施工过程中的安全及正常使用状态下受力合理,以无背索曲塔曲梁斜拉桥——东莞水道桥为工程背景,采用MIDAS/CIVIL空间有限元分析软件,分析在钢主梁悬臂施工前拆除支架,同时,钢主梁节段与对应主塔节段同步悬臂施工的情况下,对施工工期、造价、主塔应力及变形、主梁的应力及变形、拉索初拉力的影响。结果表明：（1）优化施工顺序后,结构传力更明确,能有效缩短工期,节省工程投资。（2）优化前后主塔应力分布规律一致,应力影响小;优化后内、外弧侧主塔位移不对称性明显,对主塔x方向位移影响较大。（3）优化后对钢主梁受力有所改善,对混凝土主梁受力影响小;主梁z方向位移影响较大,发生在主跨3/4跨径处,需要调整施工预拱度。（4）优化施工顺序后,2#~5#拉索初拉力均有所增大,拉索安全系数均满足设计规范要求。

In order to optimize the construction sequence of curved-pylon and curved-girder cable-stayed bridge without back stay,to simulate the overall construction process of the bridge is simulated to ensure safety during construction process and reasonable force state of structure during normal service. On the project background of Dongguan waterway bridge,which is a curved-pylon and curved-girder cable-stayed bridge without back stay,by using the spatial finite element analysis software MIDAS / CIVIL,under the condition of remove bracket before steel girder cantilever construction and cantilever construction between girder segment and the corresponding pylon segment at the same time,the influences of construction period,construction cost,stress and deformation of the girder and pylon,and initial force of the cable are analyzed. The result shows that（ 1） After optimization of construction sequence,force transmission is clearer,the construction period can be shortened effectively,and the project investment can be saved;（ 2） Stress distribution pattern is unanimous before and after optimizing construction sequence,the stress influence is small. Asymmetric deformation is more obvious between the inner arc side and the outer arc side,deformation in x direction ofpylon is particularly larger.（ 3） After the optimization,the stress state of the steel girder shows some improvement,and the stress change of the concrete girder is small. The influence of girder deformation in z direction is larger which occurred at 3 /4 of the main span,and the camber of construction should be adjusted.（ 4） The initial forces of the cables from No. 2 to No. 5 have an increase after the optimization of construction sequence,and the cable safety factor meets the requirement of design specifications.