Research on the Cables Replacement Sequence of Long Span Cable-stayed Bridge with Hybrid Girder
In order to study the influence of cable replacement on structural internal force and displacement of hybrid girder cable-stayed bridge,and to find the optimal replacement sequence of cable-stayed cables of long span cable-stayed bridge,in the paper,based on the cables replacement project of Guangzhou Hedong Bridge with 360 m in main span length,and aiming to save time and ensure the structural safety of cable replacement process,the combined cable replacement sequence is studied.Firstly,a refined finite element model of the bridge is established,and the reference state of the bridge before cable replacement is determined,and its correctness is verified.Secondly,according to the confirmed principle of cable replacement from long cable to short cable,the construction process simulation analysis is carried out based on a symmetrical replacement of a pair of cables with the same cable number in a single tower.On this basis,a kind of classification optimization idea is proposed that all stay cables of the bridge are classified into long cable area,middle and long cable area and short cable area.Finally,taking typical cables in each cable area as objects,the increment method is used to compare and analyze the changes of key structural parameters and adjacent cable forces under different cable unloading schemes.Considering the factors such as construction difficulty and mutual influence of the two towers,the suggested scheme of combined cable replacement sequence of the whole bridge is determined as follows:the long cable area is implemented according to the basic scheme.The middle and long cable area is optimized to antisymmetrically replace four stay cables at a time for the two towers,and the short cable area is optimized to replace eight stay cables of the same cable number at a time for the whole bridge.Therefore,cable replacement cycle of the bridge is optimized to 32 times from 72 times in the basic scheme,and the construction duration can be greatly shortened.
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