Yuto Tada

Study on the Buckling Strength of Compression Diagonal in Steel Truss Bridge with Two Corrosion Breaks on One Side

Eiji Iwasaki

Many of Japan’s bridge infrastructures were constructed intensively during the period of rapid economic growth, and a large number of these bridges have now been in service for several decades. As a result, the proportion of aging bridges has been steadily increasing, and the deterioration of structural performance and durability has become a serious concern. Meanwhile, it is unrealistic to maintain all bridges at a uniformly high standard. Therefore, establishing clear maintenance priorities is essential. On the other hand, steel truss bridges are known to have low redundancy. Furthermore, the stress state of compression diagonal is complex, requiring finite element analysis for evaluation, which is time-consuming. As a result, making prompt decisions regarding the necessity of repairs remains challenging.
To address this issue, Iwasaki et al. proposed a simplified method for evaluating the buckling strength of compression diagonal with a single corrosion break. However, their method does not consider cases with two corrosion breaks. When a steel truss bridge has two corrosion breaks on one side, the difference in buckling strength between the two cases is small if the spacing between the corrosion breaks is large. Accordingly, this study focused on the buckling strength of compression diagonal in steel truss bridge with two corrosion breaks on One Side. Moreover, the buckling strengths of the two cases were compared.
Elastic–plastic analyses were conducted using a finite element method (FEM) analysis program, and multiple analytical cases were examined in which the length  of a corrosion break was varied stepwise. Furthermore, the results of the two cases were compared to assess the applicability of the method.
As a result of study, the method for evaluating the buckling strength of compression diagonal with a single corrosion break, was applicable to cases with two corrosion breaks.