Car Load Patterns Of Continuous Curved Girder Bridge Design Discussed

With China's rapid economic development,the number of the city multi-level crossing bridge are increasing very fast. Curve beam especially small and medium-span continuous Curve beam, has been very widely used. Most of the previous studies focused on single-span Curve beam. Auto-load standards have not considered the effect of Curve beam application.Standards to guide the design is lack and there are very few experiences.In recent years, the Ministry of Construction issued《The Standard of loadings for the Municipal Bridge Design》(CJJ77-98) and the Ministry of Traffic promulgated the《Technical Standards of Highway Engineering》(JTJ B01-2003) which make the issue even more important, because in cities bridge designing it is required to use the above two standards sometime.Although the purpose of the study is to solve the technical issues of designing the Overpass at SanChaJi Xiangjiang River Bridge's east edge in Changsha City,In this article , the scope of the common design has also been considered . The structure is determined by 108 joint box girder which select seven kinds of section (3×17．75m,5×17．75m, 6×17．75m, 7×17．75m, 7×20m, 7×25m, 7×30m) and four kinds of beam width (10．5m, 11．5m, 12．5m and 14．0m ),radius range from six different curvature (40m,65m,100m,200m,150m and∞). In model building,general-purpose finite element software has been used. Finite element model has been constructued by spatial beam elements method. Internal forces under the condiction of constant loading and motor-20 level, pegging-120 level, the urban-A level,HL-93 level, and the class highway vehicle load has been calculated .After analyzing the results of the above calculations, summed up the relationship between the the five kinds of car load models . Through the analysis above,we come to the following conclusions:In the scope of this analysis,the design should under the control of urban-A level;the effect of the curvature on the internal forces , Span on the internal forces , the bridge width on the internal forces have been analyzed;The totally different character of mechanical performance has been described for the first time under the condiction of continuous curve beam in whole or in part in hinge points Supporter compared with the corresponding full torsion beam.Views of the author have been given after certificating the formula of the many conditions of the curved beam which could treat as linear beam described in the literatures; Useful suggestions which has not only improved the quality of design, but a significant reduction in workload and improvement of speed have been given to the designing of background project.