Steel bridge deterioration data in Japan and modelling

Abstract

In the last decade, the Ministry of Land, Infrastructure, Transport and Tourism of Japan has inspected 24 000 highway bridges with a new ‘segmental’ data-recording protocol for bridge maintenance. The data-recording units (‘segments’) are subdivisions of structural components and elements, each containing information on the extent of 26 designated types of damage. This paper analyses the deterioration characteristics (such as average deterioration trend equations and variabilities) of steel I-girder highway bridges. Inspection data show that the new protocol can express the difference in deterioration states evolving within the same element, such as girder ends and span centres for girders, and the influence of the simultaneous existence of different damage types on the rate of deterioration, for example that efflorescence seems to accelerate the development of reinforced concrete deck fatigue. The data also show that deterioration trend curves sometimes mislead data-driven management due to uncertainty in damage extent probability distributions.