Based on a partially earth-anchored cable-stayed bridge with 1218m main span and composite beam, the parametric study of this bridge type was conducted in this paper. The bridge was simulated with space pole department model, in which the beam element was used to model girder and tower, the truss element was used to model stayed-cable whose sag effect was corrected by Ernst theory. The load cases considered in analysis include: dead load and live load. The analysis content include: the girder bending moment, the girder axial force, the girder stress, the tower flexural moment, the tower axial force and the tower stress.

Based on a partially earth-anchored cable-stayed bridge with 1218m main span and composite beam, the mechanical analysis of this bridge type was conducted in this paper. The bridge was simulated with space pole department model, in which the beam element was used to model girder and tower, the truss element was used to model stayed-cable whose sag effect was corrected by Ernst theory. The load cases considered in analysis include: the completion state, the live load, the temperature load and other load combination. The analysis content include: the structural deformation, the structural internal force, the structural stress.

Effects of stiffness, carrying efficiency and fatigue of the end anchor cable on the mechanical behavior of long span cable-stayed bridge, were discussed respectively. Firstly, the concept of the effective stiffness and the stress ratio were introduced to discuss the effects of the dead load stress level and the stress ratio on the effective stiffness of the end anchor cable. Secondly, the effect of the cable material on the vertical carrying efficiency of the structure was analyzed. Finally, the main influential factors on the fatigue performance of the end anchor cable were analyzed in detail. It is shown that improving the dead load stress level and keeping the low stress ratio would increase the effective stiffness of the end anchor cable. The section of the end anchor cable effects on stiffness of the structure under high stress level. It can be drawn that as a novel material, The CFRP end anchor cable will increase the load carrying level of the long span cable-stayed bridges. It can also be concluded that the length of side span and main span, the height of pylon, the area of the cable section and the live load collection degree are all the main effective factors to the stress amplitude of the end anchor cable. It is suggested that in the practical design of large span cable-stayed bridge, all the effective factors together with the global state of the structure should be taken into account comprehensively.