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The new ASCE 7-16 Chapter 6 offers a comprehensive and practical methodology for the design of structures for tsunami loads and effects. While it provides prescriptive tsunami loading and design requirements, Chapter 6 also allows for the use of performance-based nonlinear analysis tools. However, the specifics of load application protocol and system and component evaluation for such a nonlinear approach are not provided. This paper presents a procedure for performing nonlinear static pushover analysis for tsunami loading within the framework of the ASCE 7-16 standard. Through this approach, the user can both estimate the effective systemic lateral load-resisting capacity of a building and the local component demand. This enables the identification of deficiencies in structural elements with respect to the ASCE 7-16 standard acceptance criteria. To demonstrate the procedure, a prototypical reinforced concrete multistory building exposed to high tsunami hazard on the US Northwest Pacific Coast is assessed. This is a building with sufficient height to provide last-resort refuge for people having insufficient time to evacuate outside the inundation zone. The results of the nonlinear static pushover analyses show that the structural system has sufficient lateral strength to resist ASCE 7-16 prescribed tsunami loads, but fails the checks for component-based loading, with the exterior ground-story columns observed to fail in flexure and shear. The example demonstrates that use of the tsunami nonlinear static analysis procedure allows the identification of structural deficiencies such that a targeted strengthening of the building can be conducted (i.e., flexural and shear strengthening of the seaward and inland columns for the case study building presented), leading to significantly reduced costs.

Supplementary data: The following is the Supplementary data to this article: Acrobat PDF file (2MB) available at: https://ars.els-cdn.com/content/image/1-s2.0-S2212420921007329-mmc1.pdf Copyright © 2022 The Authors. Very large tsunamis are associated with low probabilities of occurrence. In many parts of the world, these events have usually occurred in a distant time in the past. As a result, there is low risk perception and a lack of collective memories, making tsunami risk communication both challenging and complex. Furthermore, immense challenges lie ahead as population and risk exposure continue to increase in coastal areas. Through the last decades, tsunamis have caught coastal populations off-guard, providing evidence of lack of preparedness. Recent tsunamis, such as the Indian Ocean Tsunami in 2004, 2011 Tohoku and 2018 Palu, have shaped the way tsunami risk is perceived and acted upon. Based on lessons learned from a selection of past tsunami events, this paper aims to review the existing body of knowledge and the current challenges in tsunami risk communication, and to identify the gaps in the tsunami risk management methodologies. The important lessons provided by the past events call for strengthening community resilience and improvement in risk-informed actions and policy measures. This paper shows that research efforts related to tsunami risk communication remain fragmented. The analysis of tsunami risk together with a thorough understanding of risk communication gaps and challenges is indispensable towards developing and deploying comprehensive disaster risk reduction measures. Moving from a broad and interdisciplinary perspective, the paper suggests that probabilistic hazard and risk assessments could potentially contribute towards better science communication and improved planning and implementation of risk mitigation measures. COST (European Cooperation in Science and Technology); Royal Society, UK (grant number CHL\R1\180173); Severo Ochoa Centers of Excellence Program (CEX 2018-000797-S) funded by MCIN/ AEI /10.13039/501100011033; Lloyd's Tercentenary Research Foundation, the Lighthill Risk Network, and the Lloyd's Register Foundation-Data Centric Engineering Programme of the Alan Turing Institute.

This paper presents a comprehensive comparison of different dynamic and static approaches for assessing building performance under sequential earthquakes and tsunami. A 10‐storey reinforced concrete seismically designed Japanese vertical evacuation structure is adopted as a case study for the investigation. The case study building is first assessed under sequential earthquake and tsunami nonlinear response history analyses: the first time this is done in the literature. The resulting engineering demand parameters are then compared with those obtained when the analysis procedure is systematically simplified by substituting different static approaches for the nonlinear response history analyses in both the earthquake and tsunami loading phases. Different unloading approaches are also tested for the cases when an earthquake pushover is adopted. The results show that an earthquake nonlinear response history analysis, followed by a transient free vibration and a tsunami variable depth pushover, provides the best alternative to full dynamic analyses in terms of accuracy and computational efficiency. This structural analysis combination is recommended and has the advantage that it does not require the tsunami inundation time history to be known in advance. The proposed double pushover approach is instead deemed only suitable for the collapse assessment of regular low to mid‐rise buildings and for the development of collapse fragility functions. An important observation made is that sustained earthquake damage seems not to affect the tsunami resistance of the case study building when the fully dynamic analysis is carried out for the sequential loading. This observation will be the subject of future work.

The failure of hospitals in recent tsunami have caused extensive social and economic losses. A simple but quantitative approach is required to assess the resilience of healthcare systems to tsunami, which relates not only to hospital building integrity, but also to maintaining hospital functionality. This paper proposes a new tsunami relative risk index (TRRI) that quantifies the impact of tsunami on critical units, (e.g. Intensive Care Unit, Maternity Ward, etc) in individual hospitals, as well as the impact on service provision across a network of hospitals. A survey form is specifically developed for collecting of field data on hospitals for the TRRI evaluation. In its current form TRRI is designed for hospital buildings of reinforced concrete construction, as these are the building types most commonly used worldwide for housing critical units. The TRRI is demonstrated through an application to three hospitals located along the southern coast of Sri Lanka. The TRRI is evaluated for three potential tsunami inundation events and is shown to be able to identify issues with both the building and functional aspects of hospital critical units. Three “what-if” intervention scenarios are presented and their effect on the TRRI is assessed. Through this exercise, it is shown that the TRRI can be used by decision makers to simply explore the effectiveness of individual and combined interventions in improving the tsunami resilience of healthcare provision across the hospital system.

Many coastal regions lying on subduction zones are likely to experience the catastrophic effects of cascading earthquake and tsunami observed in recent events. The response of the structure to tsunami is difficult to quantify through damage observations from past events, which often provide information on the combined effects of both perils. Hence, the use of analytical methodologies is fundamental. The authors have recently proposed a nonlinear static pushover procedure for the design and assessment of structures for tsunami within the framework of ASCE 7-16 provisions. The latter offer a comprehensive and practical methodology for the design of structures for tsunami loads and effects. While they provide prescriptive tsunami loading and design requirements, they also permit the use of performance-based analysis tools. However, the specifics of load application protocol, and system and component evaluation are not specified. Through the proposed approach, the user can estimate the effective lateral-resisting capacity of a building. In addition, by applying the component loading procedure, the user can identify the structural elements that may need to be strengthened to meet the code acceptance criteria. For this purpose, a prototypical reinforced concrete multi-storey building exposed to high tsunami hazard in the USA Northwest Pacific coast is assessed. Based on the acceptance criteria of ASCE 7-16 provisions, the lateral-load resisting system needs to be strengthened to resist tsunami loading. Overall, the use of the tsunami nonlinear static analysis procedure is found to significantly reduce the extra-costs associated with tsunami strengthening of the building.

The robustness of a seismically-designed steel self-centering moment-resisting frame (SC-MRF) under a column loss scenario is numerically assessed. The prototype SC-MRF is equipped with post-tensioned bars and optimised stainless steel energy dissipation devices. The SC-MRF was modelled in full detail using solid finite elements. The numerical model was calibrated using results from previous tests on post-tensioned beam-column connections and isolated component tests on the energy dissipation devices. Quasi-static analyses were carried out to identify the failure modes of the SC-MRF under a column loss scenario. Nonlinear dynamic analyses were also performed to evaluate the dynamic response of the frame and to assess the acceptance criteria against progressive collapse according to current formalised procedures. The results show that the SC-MRF has superior robustness and it can guarantee a high level of safety under a sudden column loss scenario due to the high fracture capacity of the stainless steel energy dissipation devices and the tie force resistance provided by the post-tensioned bars.

Various organizations and institutions store large volumes of tsunami-related data, whose availability and quality should benefit society, as it improves decision making before the tsunami occurrence, during the tsunami impact, and when coping with the aftermath. However, the existing digital ecosystem surrounding tsunami research prevents us from extracting the maximum benefit from our research investments. The main objective of this study is to explore the field of data repositories providing secondary data associated with tsunami research and analyze the current situation. We analyze the mutual interconnections of references in scientific studies published in the Web of Science database, governmental bodies, commercial organizations, and research agencies. A set of criteria was used to evaluate content and searchability. We identified 60 data repositories with records used in tsunami research. The heterogeneity of data formats, deactivated or nonfunctional web pages, the generality of data repositories, or poor dataset arrangement represent the most significant weak points. We outline the potential contribution of ontology engineering as an example of computer science methods that enable improvements in tsunami-related data management.

Seismic dampers with high post-yield stiffness were recently proposed by the authors as the main energy dissipative system in a seismic-resistant steel frame. The dampers are hourglass-shaped pins made of duplex stainless steel and their high post-yield stiffness significantly reduced the residual drifts of the frame after the design earthquake. This work evaluates the cyclic behaviour of the proposed dampers both experimentally and numerically. Two different geometries of full-scale prototype dampers were tested under various standard and random cyclic loading protocols in a configuration that reproduced the damper-brace connection in the actual steel frame. The results of fourteen tests showed that the proposed dampers possess excellent hysteresis and fracture capacity. Following the tests, explicit numerical simulations were carried out using the Abaqus software. Geometry-independent fracture criteria were calibrated using the results of monotonic and cyclic tests on coupon specimens made of duplex stainless steel, and explicitly included in the numerical simulations of the dampers. The finite element models are able to accurately capture the initiation and evolution of fracture in the prototype dampers subjected to both standard and random cyclic loading histories. The results can be used to calibrate reliable macro-models for seismic collapse simulations of the proposed frame.

This paper investigates the behavior of a typical Chilean reinforced concrete wall building under sequential earthquake and tsunami actions using a double pushover analysis approach. A real concrete wall structure that was damaged after the M w = 8.8 2010 Maule earthquake is considered as a case study building and a simplified nonlinear finite element model of a fictitious slice of the building is subjected to earthquake and tsunami loading in sequence. The analysis of the building under these loadings consists of three stages: the structure is first subjected to seismic loading by means of a pushover analysis until a specific damage state is reached; then a pushover with the same load pattern but in the opposite direction is applied until the shear at the base is zero; and finally, the building is subjected to tsunami loading by means of a variable depth pushover analysis until the maximum capacity is reached. Different tsunami load cases are considered in this study, varying the Froude number and the direction of the tsunami loading. The results show that the tsunami response of the building is mainly dependent on the Froude number of the tsunami flow; however, when the seismic damage is severe, the tsunami capacity of the building is found to be reduced. This is more likely to occur when the effect of the tsunami increases the damage previously induced by the earthquake in the same direction.

A dual seismic-resistant steel frame, which consists of a moment-resisting frame equipped with high post-yield stiffness energy-dissipative braces, is proposed and numerically evaluated. Replaceable hourglass shape pins made of duplex stainless steel with high post-yield stiffness and large energy dissipation and fracture capacity are in series connected to conventional steel braces. Moreover, replaceable fuses are introduced in the beams at the locations where plastic hinges are expected to develop. A performance-based seismic design procedure and appropriate capacity design rules are used to design the dual frame, while its seismic performance is evaluated with advanced numerical simulations using experimentally validated shell–solid finite element models and simplified beam element models. The numerical results show that the dual frame has adequate stiffness and energy dissipation capacity to control peak storey drifts (i.e. non-structural damage), while plastic deformations (i.e. structural damage) are isolated within the replaceable pins of the braces and the beam fuses. In addition, the high post-yield stiffness of the pins, combined with the appreciable elastic deformation capacity of the moment-resisting frame, results in significant reduction of residual storey drifts, which are found to have a mean value of 0.06% under the design earthquake and a mean value of 0.12% under the maximum considered earthquake. These values indicate a superior residual storey drift performance compared to steel frames equipped with buckling restrained braces, and highlight the potential of the proposed dual frame to help steel buildings to return to service within an acceptable short time in the aftermath of a strong earthquake.

This paper presents ultralow cycle fatigue tests and the calibration of different fracture models for duplex stainless-steel devices of high seismic performance braced frames. Two different...

Many coastal regions lying on subduction zones are likely to experience the catastrophic effects of cascading earthquake and tsunami observed in recent events, e.g., 2011 Tohoku Earthquake and Tsunami. The influence of earthquake on the response of the structure to tsunami is difficult to quantify through damage observations from past events, since they only provide information on the combined effects of both perils. Hence, the use of analytical methodologies is fundamental. This paper investigates the response of a reinforced concrete frame subjected to realistic ground motion and tsunami inundation time histories that have been simulated considering a seismic source representative of the M9 2011 Tohoku earthquake event. The structure is analysed via nonlinear time-history analyses under (a) tsunami inundation only and (b) earthquake ground motion and tsunami inundation in sequence. Comparison of these analyses shows that there is a small impact of the preceding earthquake ground shaking on the tsunami fragility. The fragility curves constructed for the cascading hazards show less than 15% reduction in the median estimate of tsunami capacity compared to the fragility functions for tsunami only. This outcome reflects the fundamentally different response of the structure to the two perils: while the ground motion response of the structure is governed by its strength, ductility and stiffness, the tsunami performance of the structure is dominated by its strength. It is found that the ground shaking influences the tsunami displacement response of the considered structure due to the stiffness degradation induced in the ground motion cyclic response, but this effect decreases with increasing tsunami force.