Abstract
It is necessary to immediately decide whether repair, in particular, emergency repair is necessary due to corrosion reduction of gusset plate on the lower chord in steel truss bridges. Incidentally, since the thickness of the gusset plate is determined from the stress state in the neighborhood of the connecting portion between the diagonal member and the gusset, even thought the requirement for thickness of the gusset plate is not satisfied, the possibility of necessary to immediate repairing is seem to be low. On the other hand, since the stress states are complicated, finite element analysis is used for checking this part and this work is takes much time. Therefore, in this paper, a method to quickly and easily evaluate the stress state of this part is proposed by the equilibrium condition and some assumptions. In addition, it shows the residual thickness when von Mises stress of this part due to the corrosion reduction is equal to the allowable stress, and suggests maintenance policy based on this plate thickness.
