| In recent years, with the development of the bridge, the number and span of bridge isincreasing, and its type becomes more and more plentiful. But short and medium span bridgesstill occupies an important position. At present,“Chinese Specification†about the impactfactor only consider the structure of natural frequency, it does not consider the vehicle’sdynamic performance and deck unevenness. And there are also a lot of drawbacks aboutcalculation method of impact factor. Therefore the research of bridge impact factor hasbecome a research hotspot and difficulty. It is of great significance studying impact factor,especially for short and medium span bridge to broaden the bridge structure theory and tocarry out bridge structure evaluation.In this paper,typical simply supported hollow beam bridge, continuous small box girderbridge are taken as the research object, small-sized girder bridge impact factor formulaconsidering different deck pavement is studied. The paper use the ANSYS APDL languageprogram and nine degrees of freedom of three-axis space vehicle model to carry out bridgestructure dynamic analysis, so the deflection and moment curve of the bridge structure areobtained. The variation between impact factor and type of bridge, span pavement, speed thespecification method are comparied with each other. The results show that the impact factor ofedge beam is larger than the middle beam. When the vehicle’s speed increase or the spanreduce, the impact factor became larger. The impact factor in the C-level deck pavement isgreater than the national specification,“General Code for Design of Highway Bridges andCulverts (JTG D60,-2004)†Finally, the Origin software is used to fit the calculated impactcoefficient, then the impact factor formula of simply supported hollow plate girder andcontinuous small box girder bridge is obtaind about different deck pavement and naturalfrequency.The proposed calculation method can provide a reference for the structure performanceevaluation of the relevant type of bridge, and also provide a reference for the calculation of aspecification impact factor. |
