Equivalent simulation for steel truss girders

Steel truss girder is usually used for long span bridges which require much rigid stiffness for heavy loads, such as railway or high way with double decks. Since the fine finite element models for some special analysis are not convenient, researches on the simplification of stiffen girders for finite element models are presented in this paper. Focusing on the characteristic of construction control analysis, equivalent main frame for steel truss girders with double decks is proposed, in which the vertical stiffness of girder is relatively accurate. Finite element model for the construction control analysis is established. Minpu Bridge is taken as an example, three different finite element models are established, modeled with beams and shells (Model 1), modeled with single beam for main girder (Model 2) and modeled with equivalent stuffiness for girders (Model 3). Model 1 can be used for static and dynamic analysis with web members between decks considered. Model 2 is mainly used for earthquake and wind resistant analysis and Model 3 can be employed for construction control analysis. The simplification of steel truss girder provides some references for the simplified analysis of bridges of the same kinds.