Development Of A Spacial-isoparametric-element-based Bridge Analysis Program Considering The Effect Of Tendons

The paper briefly introduced historical development of bridge analysis software, and presented a self-made bridge structure analysis program, which can analyses bridge structures with spatial solid elements, and take into account the spatial effect of prestressing force.The line shapes of tendons were fitted by algebraic equations of cubic parametric curve in order to obain second order continuity. Basing on spatial eight-node isoparametric elements, the geometric description, effect analysis and loss calculation of prestressing tendons were studied, and a two-staged simulating method was put forward for analysis of prestressing force spatial effect. This method can directly simulate the prestressed tendons without increasing the total number of elements, and solve the problem about the analysis of the spatial stress state of prestressed concrete bridge. The sparse direct solver method was used in self-programming, and can easily and effectively solve large sparse matrixes.Taking a prestressed concrete simple-supported channel beam as the investigated subject, the author studied the three-dimensional stress distribution of the main girders, the transversal distribution of longitudinal stress of girder's upper and lower flanges , and the spatial effect of prestressing force. The result showed that the self-made program can better describe the condition of the spatial stress of the simple-supported channel beams and analyze the spatial effect of the three-dimensional prestressing tendons.The simulation analysis of prestressed concrete bridges can be easily and effectively completed by the program presented here. It had been successfully applied to actual structures and provide the design modification with reliable data.