Geometric Shape Control of Cantilever Assembled Cable-Stayed Bridge Based on Unstressed State Method

In view of the problem of geometric shape control of the cantilever assembled cable-stayed bridge,the Suiyan Road Cable-Stayed Bridge was cited as an example and a method for the geometric shape control of main girder of the bridge based on the unstressed state method theory and taking the geometric shape of manufacturing of the steel box girder for the main girder as the goal was proposed.The bridge as cited is a single-pylon and double-cable-plane structural system with rigid fixity of its pylon and girder and with symmetric span arrangement.The MIDAS Civil was used to set up the finite element model for the bridge and to analyze the geometric shapes of manufacturing and assembling of the steel box girder of the bridge under the action of different temporary construction loads.The results of the analysis reveal that the geometric shape of assembling of the bridge changes with the changing of the temporary construction loads.The geometric shape of manufacturing is the stable amount of the structure and as long as the unstressed state amount of the blocks of the girder is kept to a given amount,the unstressed geometric shape will be the only.At the time the actual bridge is assembled,the bridge should be assembled according to the included angles of the geometric shape of manufacturing and in spite of the changing of the construction process,the internal forces and displacement of the final completed bridge will be agreeable with those of the ideal target state.