The Application Of Finite Nodal-Line Method In The Mechanics Behavior Analysis Of Single-Box Two-Cell Girders

Box girders are widely used in the upper structure of bridges for their lower self-gravity,better torsion and bending performance,and great spanning capacity.Therefore,the analysis and reseach of box girder structures has an important significance in theoretical and engineering.However,because of the complexity of their cross sections,the traditional beam theory and numerical computational method are difficult to accurately perform the coupling behavior of bending and torsion under asymmetric load.A unified analytical beam model and a finite nodal-line method are thusly employed so as to analyze the mechanics behavior of the single-box double-cell girder under lateral force and restrain torsion and free vibration.Some conclusions are obtained,which have important value for the design and the analysis of box girder structures.The main work can be listed as follows:(1)The current situation of the development and problems existing in box girder bridge structures are introduced;(2)A new approach—Finite Nodal-Line Method(FNLM)for the analysis of box girder structures is presented;(3)The application of FNLM on the analysis of single-box double-cell girders are studied;(4)The mechanics characteristics of single-box double-cell girders in restrain torsion are investigated.And the formula for obtaining the location of a torsion center is developed;(5)The dynamic property of a simply supported single-box double-cell-girder bridge is analyzed;(6)Some problems pertinent to more complex utilization of FNLM are discussed.