Supplied Sediment Tracking for Bridge Collapse with Large-Scale Channel Migration

Takuya Inoue,Jagriti Mishra,Yasuyuki Shimizu,Tamaki Sumner,Kazuo Kato

doi:10.3390/w12071881

Takuya Inoue, Jagriti Mishra + Show 3 more

Open Access

https://doi.org/10.3390/w12071881

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Abstract

Here, we provide a numerical model that assigns an identification number to trace sediments and also identify the source of sediment supply. We analyze the efficacy of our model by reproducing the reach-scale field observations from flooding events in 2010 and 2016 that affected Kyusen Bridge over the Bebetsu River, Hokkaido, Japan. Our simulation results can successfully reproduce and trace the formation of bars caused by sediment supply in the study region. Our study also suggests a strong relationship between bank erosion rate, sediment supply and flow-discharge. The bank erosion rate is higher when sediment supply increases, and bank erosion reduces as flow discharge goes down. The model can also replicate the changes in a bed concerning sediment supply and was used to reproduce the bridge-abutment failure caused by the 2016 flooding with large sediment supply and the bridge-pier failure caused by the 2010 flooding with less sediment supply.

Highlights

The stability of bridge foundations across the globe suffers from erosion problems and bridge failures during floods
96% of the damaged bridges were over steep slope rivers with bed slopes from 0.0025 to 0.04, and the river beds tended to rise due to large amounts of sediment transported from mountain regions [4]
The objective of this study is to evaluate the effect of sediment supply on channel migration and bridge damages through numerical tracer simulation

Summary

Introduction

The stability of bridge foundations across the globe suffers from erosion problems and bridge failures during floods. 96% of the damaged bridges were over steep slope rivers with bed slopes from 0.0025 to 0.04 (mainly, channel sections lying from lower parts of mountain valleys to upper parts of alluvial fans), and the river beds tended to rise due to large amounts of sediment transported from mountain regions [4]. These abovementioned data suggest that increased sediment supply can induce stream meandering and bank erosion in steep slope rivers. An understanding of channel morphodynamics, including sediment supply effects, is important for the protection and maintenance of bridges

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