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On 30 October 2020, an earthquake of Mw 6.9 hit the Aegean coasts of Turkey and Greece. The epicentre was some 14 km northeast of Avlakia on Samos Island, and 25 km southwest of Seferihisar, Turkey, triggering also a tsunami. The event has been followed by >4,000 aftershocks up to Mw 5.2 The Earthquake Engineering Field Investigation Team (EEFIT) has immediately gathered a team to conduct a hybrid reconnaissance study, bringing together remote and field investigation techniques. The mission took place between 16 November and 17 December, inclusive of three sets of field study carried out by the field crews for building damage assessment in the affected areas in Turkey and Greece under the coordination of the remote team. The mission also aimed to assess the viability of alternative data sources for an appraisal of the future viability of hybrid missions. This paper summarises the mission setup and findings, and discusses the benefits of and difficulties encountered during this hybrid reconnaissance activity.

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.

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.

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...