Although grillage method is an effective method of analyzing bridge deck,it has not been widely used in analyzing simply-supported hinged joint slab for the restriction of that the traditional method can t be used resonably in simulating the hinged joint.

Based on basic principles of grillage an improved grillage model of making the vertical constraint of cross beam ends couple at the same hinged joint to simulate longitudinal hinged joint was proposed.

This article gives detailed description of the reason of failure,repairing method and process for the union articulation in the first maintenance to such a project in China.