Basic Study on The Stability of Estimating Spring Constants of Bearing Based on The Influence Line

Abstract

One of the typical examples of bridge deterioration is bearing restraint due to corrosion or other forms of damage. When bearings are subjected to unexpected restraint, fatigue cracks occur around the sole plate. Therefore, it is very important to quantitatively evaluate the condition of bridge bearings. The authors estimated the rotational spring constants of the bearings based on the influence lines in a previous study. An index Ir for the rotational resistance of bearings calculated from the deflection angle at supports was also proposed. In the above study by the authors, it was confirmed that the shape of the influence line was distorted by Low-pass filtering for removing the noise contained in the influence line. In this study, the effect of the distortion of the influence line due to the filtering on the estimation results of the rotational spring constants is examined. In the numerical simulation, it is confirmed that the filtering reduces the deflection angle of the influence line at the support, resulting in a deviation of Ir. It is also confirmed that filtering reduces variability. In applying this to the experimental data, it is confirmed that the effect of filtering is similar to that of the numerical simulations.