Structure Parameter Sensitivity Analysis For An Extradosed Cable-Stayed Bridge

With the continuous development of bridge technology, new form of bridge structure appears constantly. Extradosed cable-stayed bridge is a new type of bridge structure among all bridges, which the stress is between continuous girder bridge and cable-stayed bridge. Due to its shorter tower, relatively rigid beam, longer no cable area, it has advantages of a superior performance, beautiful shape and good economic indicators, also has a rapid development in our country and has been widely used in the countries all over the world. In view of the situation of extradosed cable-stayed bridge at home and abroad, and based on the structure design theory of cable-stayed bridge, the structure parameter and mechanical property of extradosed cable-stayed bridge are analyzed in detail.First of all, the thesis takes Changshan extradosed cable-stayed bridge as the background. The bridge finite element model is built by the finite element analysis software Midas/Civil. With simulation of the bridge construction stage, the basic state of reasonable extradosed cable-stayed bridge stress analysis is carried out. On this basis, the sensitivity degree on tower height and bridge span is analyzed.Then, the finite element calculation is carried out for an extradosed cable-stayed bridge structure parameter sensitivity analysis, mainly for structure parameter effect on the cable tower deviation, girder alignment, internal force and stayed cable force. Next, the selection of structure parameter for an extradosed cable-stayed bridge is discussed in this thesis. According to the sensitivity degree of structure parameter that affects the structure state, the main structure parameter and the secondary structure are devided.Finally, based on the main structure parameter identification theory, the least square method is applied for bridge’s main structure parameter error identification. The control model is calculated after identifying the parameters in order to make the measured and simulated calculation coincide with the theoretical value. Construction of the next stage can be predicted according to the adjusted parameters, the comparison and analysis on the measured results are carried out, which succeed in applying the least square method in extradosed cable-stayed bridge construction control.