Study on a rational evaluation method for load-carrying capacity of existing structures (Part 2: analytical study of concrete bridge by 3D FEM)

In the 2017 revised specifications for highway bridges, the design of new bridges was transitioned to a partial factor design that takes into account errors in material strength and dimensions by multiplying each term in the verification formula for each component by a partial factor. Furthermore, the application of partial factor design methods and limit state design methods is now beginning to be considered for repair and reinforcement work during the maintenance phase. However, the provisions of the specifications for highway bridges determine partial factors, etc. for a relatively simple structural analysis method that has been used since the days of the allowable stress method, and in reality, do not systematically take into account the bridge components that affect the bridge response (hereinafter referred to as the bridge system).This is considered to be a challenge when it comes to rationally examining the load bearing capacity of existing structures. Therefore, in this paper, we focused on two points: the "bridge system" which cannot be directly considered in the existing verification method, and the "damage state" of the existing bridge, and confirmed the load bearing capacity of the existing concrete bridge using 3D FEM analysis which can take these into account. Furthermore, using these results, we proposed a method to easily obtain results that approximate those of 3D FEM analysis by multiplying the existing verification formula by the "bridge system factor" and the "damage condition factor."