Questionnaire surveys of road bridge managers and designers who apply cathodic protection were conducted on the current status and issues of the cathodic protection method and its maintenance in order to extract important points for maintenance. Moreover, a field survey of road bridges using cathodic protection and an in-depth survey of girders removed after long-term use were conducted, and the effectiveness and durability of cathodic protection, appearance changes and their effects, were evaluated. Based on the data acquired through the above surveys, maintenance procedures for the proper detection of damage, and the appropriate frequency and items of inspection and diagnosis were investigated. Further, a maintenance manual was formulated to make use of the obtained information for on-site maintenance. This paper covers the main points of this maintenance manual along with the current state of maintenance and the results of in-depth investigation of road bridges using cathodic protection.

The Modularch construction method consists in constructing an arch culvert with a large cross section by using modular precast members. Unlike rigid culverts, culverts built with this construction method employ hinges at the boundaries of the precast members, resulting in a structure that is easily aff ected by the surrounding ground conditions. Therefore, the Technical Manual was revised to incorporate fi ndings based on closer scrutiny of appropriate use conditions, verifi cation of stability during earthquakes, large shaking table tests for the purpose of ultimate state verifi cation, and cyclic alternating positive-negative loading tests, among other things. In addition, for the purpose of contributing to practical maintenance, the main points of maintenance considering the structural characteristics of this construction method were also revised.