EARTHQUAKE–TSUNAMI INTERACTION DIAGRAM CONSIDERING TWO DIFFERENT - LIMIT STATES - Analysis and numerical model results

Oct 26, 2026

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This study develops an earthquake–tsunami interaction diagram by simultaneously considering two limit states: inter-layer deformation angle and foundation uplift. A three-story building on a mat foundation, representative of tsunami damage, is modeled with soil-foundation interaction and foundation sway-rocking. Six scaled ground motions from the 2011 Tohoku earthquake and tsunami hydrodynamic force are applied to generate the diagram. Findings show the dominant limit state depends on input ground-motion characteristics, informing reinforcement strategies against tsunamis.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages6

Reading Time15 min

AccessFree to download

Introduction

Analytical Model

Building model

Soil-foundation system

Foundation uplift

EARTHQUAKE–TSUNAMI INTERACTION DIAGRAM CONSIDERING TWO DIFFERENT LIMIT STATES Thanisorn SRIKULRUANGROJ 1 and Atsushi MIKAMI2 1Student Member of JSCE, Graduate School of Science and Technology, Tokai University (4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan) E-mail: [0CTAD022@cc.u-tokai.ac.jp](0CTAD022@cc.u-tokai.ac.jp) (Corresponding Author) 2Member of JSCE, Professor, Dept. of Civil Eng., Tokai University (4-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan) E-mail: [atsushi.mikami@tokai.ac.jp](atsushi.mikami@tokai.ac.jp) This study further develops the earthquake–tsunami interaction diagram by considering two different limit states simultaneously: inter-layer deformation angle and foundation uplift. The study considered a three-story building on a mat foundation as a building typically damaged by tsunami. Six different variously scaled ground motions recorded during the 2011 Tohoku earthquake and a tsunami hydrodynamic force were applied to generate the diagram. The results indicate that the resulting dominant limit state depends on the characteristics of the input ground motions. Key Words : multihazard, soil-structure interaction, foundation uplift, inter-layer deformation 1. INTRODUCTION In 2011, the eastern coast of Japan was damaged by an extensive tsunami generated by the 2011 Great East Japan earthquake, including a large number of buildings that were critically damaged by both the ground motion and tsunami 1),2) . Mimura et al.3) reported that the multiplicatively of the sequential earthquake and tsunami damaged many structures in the coastal region. Large intensive earthquakes induce massive tsunamis that cause considerable damage to coastal structures; therefore, a method that evaluates the effects of sequential earthquake–tsunami hazards (i.e., a multihazard) is required. Studies on combined earthquake–tsunami disasters have attracted significant attention in recent years. Goda et al.4) developed a multihazard disaster model for buildings in coastal areas and demonstrated that the estimated loss values for a multihazard loss distribution exhibited significant variation. Carey et al.5) proposed a framework to evaluate the effects of a sequential earthquake–tsunami multihazard. Carey et al.’s5) proposed diagram illustrated that the resistance of a structure to subsequent tsunamis is reduced by the effects of the earthquake on the structure. Based on Carey’s suggestion5), Srikulruangroj and Mikami6) extended earthquake–tsunami interaction diagrams by considering foundation uplift as a limit state. However, whether building damage or foundation damage has a dominant effect may differ depending on the characteristics of the input seismic motion. Hence, this study attempted to further develop the earthquake–tsunami interaction diagram by simultaneously considering two different limit states: interlayer deformation angle and foundation uplift. The results of this study will provide valuable information for the effective reinforcement of buildings against tsunamis in the future. 2. ANALYTICAL MODEL (1) Building model Reports1),2) on the structural damage caused by the 2011 Tohoku earthquake and tsunami indicate that the most overturned buildings were low-rise buildings on shallow foundations. Accordingly, a threestory building on a mat foundation was considered for this study, as shown in Fig. 1. According to the TDAP III manual7), structural stiffness is considered using a trilinear model, and the relationship between shear force and shear angle is illustrated in Fig 2 . The parameters for the analytical model used in this study Fig. 1 Three-story building lumped mass model. Fig. 2 Shear force–shear angle diagram. are summarized in Table 1. (2) Soil-foundation system The stiffness and damping of the soil were represented by spring and dashpot parameters, as illustrated in Fig. 1. These soil-foundation system parameters are calculated using Eqs. (1)–(7), as proposed by G

FAQs

What two limit states are simultaneously considered in the interaction diagram?

The study considers inter-layer deformation angle and foundation uplift as two distinct limit states.

What type of structure and foundation are used in the analytical model?

A three-story building on a mat foundation is modeled to represent structures typically damaged by tsunamis.

How do the results relate the dominant limit state to the input ground motions?

The resulting dominant limit state varies depending on the characteristics of the applied input ground motions.

Oct 26, 2026

Upload by Noah