SPH MODELLING OF TSUNAMI WAVE IMPACT ON LOW-RISE STRUCTURES

Benedict D. Rogers,Lee S. Cunningham,Gede Pringgana

doi:10.9753/icce.v36v.papers.17

Abstract

This study examines the influence of low-rise structure orientations on tsunami-induced impact force. The particular focus is on low-rise structures since these often make up the majority of building stock in tsunami prone areas and are usually most vulnerable. The meshless method smoothed particle hydrodynamics (SPH) is used for simulating the tsunami flow. Multiple cube structures named A, B and C were arranged at different angles of rotation and were situated on a flat shore. Four cases were simulated with variation on the number of structures and orientation toward the tsunami direction. Case 1 comprises a single structure (SS) C without rotation (R=0 degrees) and used as the baseline, Case 2 contains multiple structures (MS) A, B and C without rotation (R=0 degrees), Case 3 includes multiple structures (MS) A, B and C with 30 degree rotation (R=30d egrees), and Case 4 consist of multiple structures (MS) A, B and C with 45 degree rotation (R=45 degrees). The simulations show that for a 2-solitary wave train the front structures generated a flow focusing effect that accelerated the bore velocity. The orientation of the multiple structures to the direction of the oncoming tsunami bore significantly affected the magnitude of the applied force, where the most effective structure orientation is provided by the 45-degree rotation. The results of this study emphasize the potential for improving tsunami resilience through appropriate positioning of structures. Importantly, such large reductions in force may provide an economic solution to building resilience in developing countries prone to tsunamis.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/WNtyTNzQ7yY

Highlights

Tsunamis cause severe damage to buildings, bridges and infrastructure across the affected coastal regions, as shown by major tsunami events including the 2004 Indian Ocean and the 2011 Japan tsunamis
Pringgana et al numerically explored the influence of onshore structures’ orientations and arrangements due to tsunami impact using the numerical simulation technique smoothed particle hydrodynamics (SPH) and the results reveal significant reductions in total force on a structure can be achieved via strategic spatial positioning and orientation
The smoothed particle hydrodynamics (SPH) numerical method has been used to investigate the influence structure orientation on the forces experienced during a double-wave impact event

Summary

Introduction

Tsunamis cause severe damage to buildings, bridges and infrastructure across the affected coastal regions, as shown by major tsunami events including the 2004 Indian Ocean and the 2011 Japan tsunamis. The impact of the tsunami depends on several factors including the tsunami wave velocity and height, which are influenced by the coastal topography. According to Ghobarah et al (2006), in a largely populated and relatively flat area of Banda Aceh, Indonesia, which was the most affected area during the 2004 Indian Ocean tsunami, the maximum tsunami inundation and runup height were 4.5 km and 6 m, respectively. The majority of the damages were due to the tsunami applied forces on the structure in the form of hydrodynamic pressure, scour, uplift and debris impact (Saatcioglu et al 2005; Ghobarah et al 2006; Mikami et al 2012; Suppasri et al 2012; Chock et al 2013). Studies indicated various strategies can be adopted to reduce wave pressures including the use of breakaway walls and the presence of openings to allow flow through the building (Thusyanthan and Madabhushi, 2008). The complex interaction between tsunami flow and structures determine the performance of structures during tsunami events

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Conclusion