Study on Dynamic Behavior of Bridge Pier by Impact Load Test Considering Scour

Myungjae Lee,Il-Wha Lee,Hyun-Seok Jung,Ki Hyun Kim,Mintaek Yoo

doi:10.3390/app10196741

Abstract

In this study, for the establishment of a safety evaluation method, non-destructive tests were performed by developing a full-scale model pier and simulating scour on the ground adjacent to a field pier. The surcharge load (0–250 kN) was applied to the full-scale model pier to analyze the load’s effect on the stability. For analyzing the pier’s behavior according to the impact direction, an impact was applied in the bridge axis direction, pier length direction, and pier’s outside direction. The impact height corresponded to the top of the pier. A 1-m deep scour was simulated along one side of the ground, which was adjacent to the pier foundation. The acceleration was measured using accelerometers when an impact was applied. The natural frequency, according to the impact direction and surcharge load, was calculated using a fast Fourier transform (FFT). In addition, the first mode (vibratory), second mode (vibratory), and third modes (torsion) were analyzed according to the pier behavior using the phase difference, and the effect of the scour occurrence on the natural frequency was analyzed. The first mode was most affected by the surcharge load and scour. The stability of the pier can be determined using the second mode, and the direction of the scour can be determined using the third mode.

Highlights

The maintenance of railway bridges is required due to their special structures and socioeconomic roles
Calculate the natural frequency because clear signals could not be obtained. These results indicate that the mode number that was most affected by the surcharge load was the first mode
The dynamic response analysis was performed on a shallow foundation used as a railroad pier through non-destructive tests

Summary

Introduction

The maintenance of railway bridges is required due to their special structures and socioeconomic roles. When flooding occurs, scouring occurs due to runoff in the ground adjacent to the bridge piers crossing the river, causing the bridge to collapse. This seriously affects the safety of people, but can cause enormous losses to society and economy over a long period of time. It is reported that the first cause of the bridge failure is not the structural defect of the bridge, but the destruction of the foundation due to scouring around the pier during flooding [1,2,3,4]. In April 1987, a bridge collapsed at the Schoharie creek in New York, USA owing to the scour that occurred on

Results

Discussion

Conclusion