Abstract
It is a burden to go through the inside of box girders, especially to pass the small opening in diaphragms, during the inspection or maintenance work. This report represents a consideration for the larger size of opening in diaphragms compared with conventional one under the conditions that it satisfies the required distortional resistance of box girder. Finite element analysis is carried out to confirm the principal factors to control distortional strength of box girder, changing the shape, size and location of opening in diaphragms. On the basis of the results of FE analysis, the rational and inspector-friendly structure of diaphragms is proposed.
