ABSTRACT
Deflection is an important index for bridges, although it is difficult to measure bridge deflections due to surrounding conditions. With expectation to the development of displacement measurement system, acceleration-based measurements have been studied, which were enabled by the development of sensors and calculation methods using double integration. However, double integration-based methods have difficulty in measuring lower frequency deflections (DC~0.1[Hz]) such as deflections of long-span bridges or deflections caused by traffic jams or temporary stops on bridge girders because of integration error. To address this problem, a method using multiple inclinometers has been investigated, by measuring the rotation of girders and then using the relationship between the rotation and deflection of the girders. In this study, a method using a multiple 3axial accelerometer has been proposed, to overcome the low accuracy and problems regarding applicability to dynamic vibration and continuous deflections seen in previous methods. Then through field testing, the applicability of the proposed method has been verified and the accuracy has also been further improved.
