The Prototype Bridge Investigation And FEM Simulative Research Of Simply Supported-Continuous System

With the development and construction of freeways,large amount of bridges are being built. High-speed driving demands good continuity and less expansion joints of the bridges. Those of multi-span,middle-length (about 25-40 metres) are of large percentage among advanced bridges. Simply-supported girder bridges with continuous decks are inferior to those of continuous girders because their decks crack easily. Owing to the complex construction of continuous girder bridges,which is laboursome and time-consuming,people have been thinking about an approach to combining the advantages of the two so as to speed up the building and reduce the work procedures. Thus the "simply-supported-continuous system" is introduced. With the popularization of such practice,the meaning of this concept has been enriched. Considering the state-of-the-art of such kind of structural system,the author gives a simulative analysis of the system with the Feiyunjiang Bridge in Wenzhou Zhejiang Province as an engineering example using three methods:3-D beam or Bar FEM,classical Plate/Shell FEM and virtual laminated element method. The Virtual Laminated Element Method may deals with many key issues in simply-supported-continuous system easily such as the matter of actual material or virtual material,mesh replacement. In light of the simulative research results,three methods are applied to analyze some controversial problems in this kind of structural system (such as the concrete pouring sequence of continuous ends,the applying sequence of pretensioned force,the removal of the temporary supports,the concrete pouring style of continuous ends,the optimization of constructional reinforcement and prestressed reinforcement). Some important conclusions are drawn:the concrete pouring sequence of continuous ends should be in accordance with the principle of "interval end";the removal of temporary supports is also on this principle (opposite to traditional opinions). At the same time,other problems such as the shrinkage and creep effects of concrete,the cracking and failure pattern,the optimization of reinforced bars and prestressed bars are also analyzed in detail. The extensive research emphases are also listed.The author strongly believes that the theoretical fruits produced in this research will certainly promote the further application of such kind of structural system and benefit our country greatly.