Tsunami loads on slab bridges

Zhonghou Xu, Bruce Melville, N. A.K. Nandasena, Colin Whittaker, Asaad Shamseldin, Farzad Farvizi

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


Coastal bridges serve as lifelines connecting affected areas to the outside world after extreme events such as tsunamis. It is thus important to predict tsunami loads applied to bridges vulnerable to tsunami attack. Most previous studies have focused on the horizontal force on bridges due to tsunamis. However, the overturning moments applied to bridges also contribute to the flexural failure of the bridge and have not been thoroughly investigated. Continuing efforts should be made to quantify tsunami-induced loads (forces and overturning moments) on coastal bridges. This study presents a series of experiments undertaken to study the tsunami loads on slab bridges using tsunami bores. Apart from the average horizontal pressure (Ph) and the horizontal (Fx) and vertical (Fz) forces, the overturning moments about the base of the pier (Myb) and the pier-deck connection (Myp) were analysed, which are closely related to the flexural failure of bridges in tsunamis. Four different pier heights were tested, as well as seven tsunami bore cases for each bridge set-up. Results show the maximum “area-adjusted momentum flux” (the product of the flow velocity squared and the contact area of the bridge in the direction of the flow) provides a better predictor for the maximum horizontal force than the maximum momentum flux, which has been used to calculate horizontal forces on emergent structures with a uniform width in the vertical direction. When a bridge is fully submerged under a tsunami, the overturning moments Myb and Myp applied to the bridge are largest at a specific pier height. Empirical equations are proposed to calculate the maximum loads (Ph, Fx, Fz, Myb and Myp) at the initial impact stage. The threshold of jump inception when a tsunami impacts a bridge has been discussed.

Original languageEnglish
Article number103853
JournalCoastal Engineering
Publication statusPublished - Apr 2021


  • Bridge
  • Experiments
  • Force
  • Overturning moment
  • Tsunami bore

ASJC Scopus subject areas

  • Environmental Engineering
  • Ocean Engineering


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