On Material,Construction and Design,the Three Key Factors for Bridge Development

Firstly, the materials such as concrete,steel products, steel tube concrete and composite material about the bridge construction applications and developing trends were presented in the paper. Secondly, the construction method and developing direction of bridge super and substructures were mentioned. Then, the bridge design was emphasized including its principle, theory system improvement and design method development. As a conclusion, material, construction and design were proved to be the three key factors in the bridge developing.