This paper describes a method of safety evaluation of concrete bridges and its verification
based upon field tests performed either under static loading by test trucks for application of the system identification(
SI) method or under dynamic loading by falling mass for application to the modal analysis. The safety
factors for flexural and shear failures were evaluated from these test results. Then, they were verified
through the ultimate load test carried out in situ on the reinforced concrete main girders isolated by cutting off
from the bridge system. Finally, the remaining life of the bridge was predicted by applying the fuzzy set theory
which deals with the subjective information of bridge engineers.