Abstract:

The accidents of bursting and cracks of the bottom plate of somecontinuous rigid bridges often occur during the stretching of the prestressing tendon and the running stage. Based on the principle of the mixed finite element, the nodes'constraint equations at the interface between beam elements and solid elements were derived. A sixspan prestressed continuous rigid frame bridge was analyzed by themixed finite element method, and the stress of the bottom flange was calculated. With the numerical solution test, it was found that the mixed finite element method had the characteristics of high precision solution and less elements. Based on computed results, a conclusion was  drawn that the radial force which was caused by the prestressing tendon settling according to the linetype of bottom plate was the main reason, and the  vertical tensile stress of concrete near bellows at webs of box girders was morethan at other sites of the bottom flange.

Key words: mix finite element; constraint equation; rigid frame bridge;box-girder; radial force