预应力混凝土斜拉桥斜拉索张拉方式比选研究

Study on the Comparison and Selection of Cable Tensioning Methods of Prestressed Concrete Cable-stayed Bridge

为研究预应力混凝土斜拉桥的最优斜拉索张拉方式,运用软件MIDAS/CIVIL模拟斜拉索张拉过程,并针对采用不同张拉方式成桥的桥梁的变形及受力变化规律进行对比分析。结果表明:斜拉索张拉索力设计为第一次35%、第二次100%可以有效降低主梁主跨最大变形和降低主塔最大偏移幅度,对于控制结构变形效果更好;第一次35%、第二次100%的张拉方式相比其他张拉方式主梁最大应力值更小,分布更为均匀;斜拉索张拉方式对于斜拉桥主梁剪力影响不大;采用不同张拉方式的斜拉桥主梁弯矩变化趋势大致相似,其中采用第一次35%、第二次100%张拉方式可有效降低主梁边跨和主跨截面的最大弯矩,成桥后主梁结构的受力更合理,安全性更高。

In order to study the optimal cable tensioning method of prestressed concrete cable-stayed bridge,MIDAS/CIVIL software was used to simulate the process of cable tensioning,and a comparative analysis was made on the deformation and force variation of the bridge with different tensioning methods.The results show that the maximum deformation of the main girder span and the maximum deviation range of the main tower can be reduced effectively when the cable tension force is designed to be 35%at the first time and 100%at the second time,which is better for controlling the deformation of the structure;the maximum stress value of girder to be 35%at the first time and 100%at the second time tensioning mode is smaller and more evenly distributed than that in other tensioning modes;the influence of cable tensioning mode on girder shear force of cable-stayed bridge is not significant;the bending moment change trend of girder in cable-stayed bridge with different tensioning modes is similar,in which to be 35%at the first time and 100%at the second time tensioning mode are adopted.The second 100%tension method can effectively reduce the maximum bending moment of the side span and the main span section of the main beam,and the stress of the main beam structure after the completion of the bridge is more reasonable and safer.