Applicability Study On Force Transfer Expansion Device For Long-Span Multi-Pylon Cable-Stayed Bridges

Application performance of a new-type force transfer expansion device on multi-tower cable-stayed bridges was studied in this thesis. This device can not only release the axial displacement, but also bear a certain amount of moment and ensure the smoothness of the deck. Based on the design of Qiongzhou Straits Bridge, the influences of force transfer expansion device on the internal force state of multi-span cable stayed bridges with different structures is studied and the applicability of the force transfer expansion device is confirmed.Finite Element modEI of bridges with different spans, different numbers of towers and different heights of pier have been established in ANSYS, which is a large scale general finite Element analysis software. ModEIs with and without the expansion device at mid-span have been analyzed to find influences on the structure. Firstly, with the set of expansion device at mid-span, the influence caused by geometric nonlinearity on the internal force and displacement of the structure has been analyzed. Then the internal force and deformation of the bridge under dead load, live load and temperature variation have been calculated and the result of the influence from the expansion device on the change of internal force and deformation were obtained. Fitting formulas of the internal force change value with three parameters, the span, pier height and temperature variation, were obtained according to the calculation results.Dynamic characteristics of multi-tower cable-stayed bridges with whether expansion device were compared and analyzed by the time history analysis method of multi-support excitation in consideration of seismic travEIing wave effect, to research the effect of expansion device on structural seismic performance. Furthermore, applicability of expansion device on structural seismic performance of multi-tower cable-stayed bridge was studied.