Field study of local scour around bridge foundations on silty seabed under irregular tidal flow
Zhang, Z. Du, S. Yang, Y. Zeng, J. Sui, T. Wei, R. Li, Z.
Zhang, Z.
Du, S.
Yang, Y.
Zeng, J.
Sui, T.
Wei, R.
Li, Z.
Publication Date
2023-08-21
End of Embargo
Supervisor
Rights
© 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/ ).
Peer-Reviewed
Yes
Open Access status
openAccess
Accepted for publication
2023-08-18
Institution
Department
Awarded
Embargo end date
Additional title
Abstract
Local scour induced by tidal flow is a major hazard for sea-crossing bridge foundations in coastal areas. The
irregular tidal flow and silt-muddy seabed environment generates a very complicated flow turbulence and
sediment transport. This paper, for the first time, presents the field measured scour holes around the Hangzhou
Bay Sea-Crossing Bridge (HBSB) under irregular tidal flow dominated water regions. The high-resolution seabed
topography around 19 bridge foundations in the south waterway of HBSB is measured from 2015 to 2020 by
using a multi-beam sonar system. The field measured data are analyzed to investigate the local scour characteristics under irregular tidal flows. Results indicate that under irregular tidal flows with stronger flood tide, the
local scour hole around every bridge foundation is slightly asymmetric and the scour depth downstream is larger
than that upstream. The slope angles at upstream, downstream and lateral sides of local scour hole are about 13◦
～18◦, which are much smaller than the Angle of Repose (AoR = 35◦) due to bidirectional scouring generated by
tidal flows. During 2015～2020, the maximum scour depths around all bridge foundations range between 1.2
De～2.5De (where De being the effective diameter of bridge foundation). The maximum scour depths vary
frequently with a fluctuation within 0.6De. Comparison between the field measured and predicted scour depth
using three available scour depth predication equations show that all prediction equations overestimate the scour
depth. As such, considering the discount effect of the varied tidal flow compared with steady current, an
improved maximum scour depth prediction equation is proposed to estimate the scour depth under tidal flow on
a silty seabed. Results show that the predicted scour depth using the proposed equation has a relative error of ±30%.
Version
Published version
Citation
Zhang Z, Du S, Guo Y, et al (2024) Field study of local scour around bridge foundations on
silty seabed under irregular tidal flow. Coastal Engineering 185: 104382.
Link to publisher’s version
Link to published version
Link to Version of Record
Type
Article
Qualification name
Notes
The article includes a Corrigendum published in 2024.