No abstract

To study the behavior changing between cable characteristics and beam characteristics, the geometric shape calculation formulae for tension components with bending stiffness are derived from ones with the boundary conditions of two ends hinged, one hinged joint and the other fixed and two ends fixed respectively. Then, using the concept of tension stiffness, the effects of Cable Characteristic Parameter on the geometric shape of tension components are studied. Analyses indicate that with the increase in the value of the Cable Characteristic Parameter, the cable characteristics of components become more obvious. That is, a bar with enormous tension can be calculated as a cable element even if its bending stiffness is large. In structure finite element analysis, more storage space and computing time could be saved as long as components are simplified with cable elements other than beam elements, the simplification should be carried out basing on the Cable Characteristic Parameter. Calculation results on a hollow beam verify that when tension increases, components’ mechanical properties gradually change from beam characteristics to cable characteristics and eventually they tend to be identical with the theoretical calculation of cable structure.

As a composite structure, the cable-stayed-suspension bridge is characterized by relatively new structure, great overall stiffness and long-span capacity, which has been proposed for the design of some extra long-span bridges. In order to research further into the mechanics characteristics of this type of structural system, the proposed preliminary design of a cable-stayed-suspension bridge with a main span of 1800m is analyzed by means of finite element simulation method. The advantages on overall stiffness in the cable-stayed-suspension bridge are summarized in comparison with the three-span suspension bridge and the single-span suspension bridge. Then, the reasons for the fatigue of the longest suspension cables in the cable-stayed-suspension bridge are also discussed in this paper.

No abstract

No abstract