### Abstract

This study developed a finite element method with the effect of soil-fluid-structure interaction to calculate bridge natural frequencies. The finite element model includes bridge girders, piers, foundations, soil, and water. The effective mass above the soil surface was then used to find the first natural frequency in each direction. A field experiment was performed to validate that the natural frequencies calculated using the proposed finite element method had acceptable accuracy. The calculated natural frequencies with the fluid-structure interaction effect are always smaller than those without this effect. However, the frequency change due to the fluid effect is not obvious, so using the soil-structure interaction model is accurate enough in the bridge natural frequency analysis. The trend of the frequency decreases with the increase of the scour depth, but the curve is not smooth because of non-uniform foundation sections and layered soils. However, when the scour depth is such that pile cap is exposed, the changes in natural frequency with the scour depth are more obvious, and this is useful for measurement of the depth using bridge natural frequencies.

Original language | English |
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Pages (from-to) | 247-254 |

Number of pages | 8 |

Journal | Soil Dynamics and Earthquake Engineering |

Volume | 55 |

DOIs | |

Publication status | Published - 2013 Dec 1 |

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### All Science Journal Classification (ASJC) codes

- Civil and Structural Engineering
- Geotechnical Engineering and Engineering Geology
- Soil Science

### Cite this

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**Determination of scoured bridge natural frequencies with soil-structure interaction.** / Ju, Shen-Haw.

Research output: Contribution to journal › Article

TY - JOUR

T1 - Determination of scoured bridge natural frequencies with soil-structure interaction

AU - Ju, Shen-Haw

PY - 2013/12/1

Y1 - 2013/12/1

N2 - This study developed a finite element method with the effect of soil-fluid-structure interaction to calculate bridge natural frequencies. The finite element model includes bridge girders, piers, foundations, soil, and water. The effective mass above the soil surface was then used to find the first natural frequency in each direction. A field experiment was performed to validate that the natural frequencies calculated using the proposed finite element method had acceptable accuracy. The calculated natural frequencies with the fluid-structure interaction effect are always smaller than those without this effect. However, the frequency change due to the fluid effect is not obvious, so using the soil-structure interaction model is accurate enough in the bridge natural frequency analysis. The trend of the frequency decreases with the increase of the scour depth, but the curve is not smooth because of non-uniform foundation sections and layered soils. However, when the scour depth is such that pile cap is exposed, the changes in natural frequency with the scour depth are more obvious, and this is useful for measurement of the depth using bridge natural frequencies.

AB - This study developed a finite element method with the effect of soil-fluid-structure interaction to calculate bridge natural frequencies. The finite element model includes bridge girders, piers, foundations, soil, and water. The effective mass above the soil surface was then used to find the first natural frequency in each direction. A field experiment was performed to validate that the natural frequencies calculated using the proposed finite element method had acceptable accuracy. The calculated natural frequencies with the fluid-structure interaction effect are always smaller than those without this effect. However, the frequency change due to the fluid effect is not obvious, so using the soil-structure interaction model is accurate enough in the bridge natural frequency analysis. The trend of the frequency decreases with the increase of the scour depth, but the curve is not smooth because of non-uniform foundation sections and layered soils. However, when the scour depth is such that pile cap is exposed, the changes in natural frequency with the scour depth are more obvious, and this is useful for measurement of the depth using bridge natural frequencies.

UR - http://www.scopus.com/inward/record.url?scp=84886299254&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84886299254&partnerID=8YFLogxK

U2 - 10.1016/j.soildyn.2013.09.015

DO - 10.1016/j.soildyn.2013.09.015

M3 - Article

AN - SCOPUS:84886299254

VL - 55

SP - 247

EP - 254

JO - Soil Dynamics and Earthquake Engineering

JF - Soil Dynamics and Earthquake Engineering

SN - 0267-7261

ER -