A new stiffness correction method based on finite element for in-service girder bridges

Aiming at the difficulty and shortage in stiffness calculation and analysis for in-service bridges, according to plane cross - section assumption and finite element theory, deduces solving equations of longitudinal N- sections stiffness, using deflection testing results to correct longitudinal stiffness of bridges, and implement real beam outdoor test to verify the theory. The experimental results show that the deflection theoretical value for each measure point in longitudinal beam, which is caculated by new article algorithm, coincides well with the experimental ones. This method can be used to calculate longitudinal stiffness defect caused by all kinds of damage, lock damage range quickly, estimate damage degree effectively, and distinguish damage condition for the whole longitudinal beam accurately. The comparison and analysis indicate that the stiffness calculated by this algorithm has higher precision than the ones calculated by bridge standard. It reflects the whole damage status for in - service bridges veritably and reliably, which is easy for the engineers to identify invisible bridge damage areas and evaluate the bridge service lives.