Tr Ansverse Distribution&Structur Al Behavior Of Cable-Stayed Bridge With Three-Planes Truss&Cable

The cable-stayed bridge with three-planes truss and cable is a new type of bridge appeared in recent years.Compared with the two-planes cable cable-stayed bridge,many differences do exist,such as more-obvious spatial performance and more-complicated transverse distribution,so that most of the structural behavior cannot be shared between the two bridge styles.At present, at home or abroad,researches are mainly done on the three-planes truss beam bridge and two-planes truss cable-stayed bridge,insufficiently on two-planes truss and cable cable-stayed one. So it is necessary to study deeply on the mechanical performance of the new type of bridge.To facilitate symmetry analysis on the mechanical performance of three-planes cable-stayed bridge,all results are based on the condition of no initial tensile stay cables.That is,through the method of combination of mechanics derivation and numerical analysis,the mechanical principle of the three-planes truss cable-stayed bridge under dead weight was discussed, the structural behavior clarified as well.The work was done as follow:(1) The distribution regularity of stay cables’tension of the three-planes truss cable-stayed bridge under dead weight was analyzed.A self-defining finite element model was established by midas/civil,which was used to analyse the factors that affect the transverse distribution of stay cables’tension, such as the stiffness of stay cables, cross beams Joints and so on.(2) Based on the principle of minimum potential energy, relatively reasonable explanation was provided for the regularity summarized previously.The stay cable’s tension expression of a simplified model of three-planes truss cable-stayed bridge’s cross section was established based on the theory of principle of minimum potential energy,then compared its results with those from FEM to analyse its mechanical principle. Meanwhile, thin-wall box girder method based on spatial analysis and two-times distribution method of three-planes truss beam bridge were briefly introduced as well.(3) Based on the previously established model by midas,models of three-planes truss beam bridge and two-planes cable cable-stayed bridge were established separately.For the first, comparative analysis of transverse distribution and simplified calculation method between beam bridge and cable-stayed one with three-planes truss was given.For the second, comparative analysis of the performance was done between two-planes and three-planes cable cable-stayed bridge.And finally, the structrural behavior of cable-stayed bridge with three-planes truss and cable was summed up systematically.(4) Using the finite element model established by ANSYS,the situation of transverse distribution of internal forces of Hutong Yangtze river bridge trusses’bars and stay cables under self weight was clarified,and also, its internal force’s distribution under three typical loads of temperature,transverse wind and support settlement were briefly analysed.