Design And Mechanical Properties Analysis On Self-anchored Combined Cable-stayed Suspension Bridge

Combined with the engineering practice, this paper gives the study and discussion about its bridge design, static properties, dynamical behaviors and seismic resistance. The main research work covers the following aspects:(1) A self-anchored combined cable-stayed suspension bridge with span of 183.2m is designed and analyzed. Force and stress of the main construction member like the beam and cable under the different status is put up, and the result shows that Zhuanghe Constructing Bridge which will be built in future meets code requirement.(2) Setting up the space model for the static properties analysis of self-anchored combined cable-stayed suspension bridge. The result tell us that compared with the earth-anchored combined cable-stayed suspension bridge, the structural rigidity of the self-anchored combined cable-stayed suspension bridge is smaller while its deflection and moment is bigger. The result calculated with elastic theory is similar to the result calculated with finite element model. Elastic theory is applicable to middle and small-span self-anchored combined cable-stayed suspension bridge. The concrete shrinkage and creep has great influence to the structure, it must be made enough importance in design. Owning to the initial force of the structure, the structural rigidity has no change basically, it can be ignored. About this bridge, its values of the moment will decrease and its deflection will increase when the number of suspender is decreased.(3) Based on the finite element principle, the dynamic model of the self-anchored combined cable-stayed suspension bridge is set up , by means of the alteration of dead load, rigidity of stiffening girder, rigidity of tower, the natural vibration character of this bridge is studied and the seismic response of self-anchored combined cable -stayed suspension bridge is analyzed by the response spectrum method . The results show that the vibration mode is closed and the natural period of vibration is short, the alteration of dead load has great influence on the structural rigidity, the alteration of the vertical rigidity of stiffening girder has a little influence on the first natural vibration character of the self-anchored combined cable-stayed suspension bridge, at the same time , the alteration of the torsional rigidity ofstiffening girder and the rigidity of tower has no influence on the first natural vibration character of this bridge . From the structural response result of the composition of different seismic loads, we can draw a conclusion that vertical vibration plays an important role in the composition, so which can not be ignored.