Application Study On The Bridge Deck System Of Long-Span Half-Through CFSTArch Bridge

The application of concrete filled steel tube (CFST) in arch bridge has solved the two difficult problems of the high strength in material and the non-bracket erection, and increased the infinite source of vitality for the development of arch bridge technique which combines the traditional culture and technique characteristic. In our country more and more CFST arch bridges are being built with the longer span, the more beautiful pattern, and the more advanced technique. Particularly, half-through CFST arch bridge has been generally chosen because of its special advantages and the graceful shape.To start with introducing the applications and developments of CFST in arch bridges, the dissertation systematically introduced the development process of long-span half-through CFST arch bridge and its construction forms and analyzed its structure and mechanic characteristics, and elucidated the purport of study on bridge deck system .Secondly, in the dissertation, the theories and methods of calculation on bridge deck system were discussed, and bridge deck system simplified as a beam was analyzed with the theory of elastically supported continuous beam and the method of deformation compatibility; through the theory of orthotropic plate being applied to analyzing the bridge deck system which was assumed an elastically supported continuous plate, certain theoretical derivations were made and some calculation formulas were given. At the same time, to acquire the satisfied results conveniently, the finite element method, which is one of the numerical analysis methods with the most extensive application and the highest efficiency, was introduced and strongly suggested in analysis and calculation.Thirdly, from the view of function, construction demand and aesthetic effect, the method, with which designing the bridge deck system's position in long-span half-through CFST arch bridges, was systematically discussed. It was analyzed how bridge deck systems' relative positions influenced the structural stability and vibration. The data of the bridge deck system's positions of some long-span half-through CFST arch bridges has been collected and analyzed by the principles of statistics. It indicates that the best position of a bridge deck system can be confirmed when the value of parameter C to measure a bridge deck system's position (ratio of the distance between deck and crown to rise) approximates to 0.6. If so, the bridge construction will possess the better lateral stability and dynamic performance and take on the stronger aesthetic feeling.Finally, basing on analyzing the characteristics of bridge deck systems in common use, the supported-continuous combinatorial bridge deck system, a kind of new type, was brought forward for the first time and calculated with MSC.Nastran software to study the influence of different types of bridge deck systems on the static and the dynamic characteristics. The results show that it makes no marked differences that the influence of different types of bridge deck systems on the inner force of CFST arch ribs, the stability and dynamic performance of bridge structure. The other important conclusion is that the supported-continuous combinatorial bridge deck system inherits so much advantage from simply supported and continuous bridge deck systems that it is regarded as the best bridge deck system of long-span half-through CFST arch bridge.