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The September 28, 2018 earthquake and tsunami, which occurred north of Palu City, Indonesia, attracted widespread interest from the scientific community due to the unusually large tsunami that occurred after a strike-slip earthquake with a relatively small moment magnitude (MW = 7.5). To understand the structural performance of buildings and infrastructure under hydrodynamic loads and their associated effects, the authors conducted field surveys in Palu City. Light wooden frame constructions and masonry infill walls were common in the area, some of which were severely damaged by the earthquake and tsunami. Reinforced concrete structures remained predominantly intact, although they suffered soil-related issues such as scour around rigid building members. Local structural failures caused by the loss of supporting soil were also observed during the field survey, resulting in an overall reduction in the stability of the inspected structures. Based on the observations made, knowledge gaps and research needs concerning coastal and structural scouring are discussed. These are tied into the latest community research activities and put in the context of a published ASCE standard chapter that discusses tsunami design. [ABSTRACT FROM AUTHOR]

The 2011 Tohoku Earthquake and Tsunami generated a massive tsunami that devastated Kujukuri Beach in Chiba Prefecture, Japan. The possibility that edge waves were involved in the propagation mechanism of the tsunami was investigated by using a numerical method. To detect the components of edge waves, the fluctuations of the simulated sea level, the variations of the power spectral and the phase, coherences, as well as the dispersed relations of the wavelength and the period, were analyzed. As a result, it was possible to conclude that there is a high probability that edge waves could have propagated around this coastline. In addition, to analyze the various types of edge waves that could be expected three additional earthquake scenarios were considered, each of them with a different magnitude and epicenter: the 1896 Sanriku Earthquake, the 1677 Empo Boso-oki Earthquake, and the 1703 Genroku Kanto Earthquake. This comparison indicates that there is a particular risk that edge waves can be generated by large earthquakes with their epicenter in the northern part of the Japan Trench. [ABSTRACT FROM AUTHOR]

Water level oscillations induced by the ground motion of an earthquake have occasionally been observed in a closed or partially enclosed water system. The generated water disturbances can induce localized flooding, boat collisions, breakage/damage of moored cables due to water disturbances, or even the capsizing of vessels. In this study, the authors focused on cases of seismic water level oscillations in canals and attempted to investigate the potential hazards of and effective countermeasures against them through numerical simulations. The proposed numerical simulation model was first validated by reproducing the water level oscillation that was actually observed at a canal in Mexico City (Xochimilco Canal) during the 2017 Central Mexico Earthquake. The method was then applied to one of the canals in Tokyo (Keihin Canal) to clarify the potential water level fluctuations that can take place due to this phenomenon. The results indicate that while the risks of local inundation would be low, small boats, which can be found in many places in the canal, are at risk of capsizing. Finally, the use of wave-dissipating blocks was found to be an effective countermeasure to decrease the potential for a significant seismic water level oscillation to take place in this canal. [ABSTRACT FROM AUTHOR]

The design of breakwater armor units against tsunami attacks has received little attention in the past because of the comparative low frequency of these events and the rarity of structures designed specifically to withstand them. However, field surveys of recent events, such as the 2011 Tohoku Earthquake Tsunami and the Indian Ocean tsunami in 2004, have shown flaws in the design of protection structures. During these extreme events, many breakwaters suffered partial or catastrophic damage. Although it is to be expected that most normal structures fail because of such high-order events, practicing engineers need to possess tools to design certain important breakwaters that should not fail even during Level 2 events. In the future, research into the design of critical structures that only partially fail (i.e., resilient or tenacious structures) during very extreme Level 2 tsunami events should be a priority; in this sense, the present paper proposes a formula that allows the estimation of armor unit damage depending on the tsunami wave height. [ABSTRACT FROM AUTHOR]

This paper presents a simplified method of analysis and design for repair using bonded rigid plates of timber beams with localized damage. This method assesses the load-bearing capacity of the connection between plate and timber and proposes two failure modes: shear stresses at the bonding interface and in the timber piece. An experimental campaign was developed to verify the theoretical model, which in this paper is limited to the problem of bending moment transfer. Ten specimens of Pinus radiata D. Don were joined with bonded-in plates and 10 with laterally bonded ones, after which they were tested for bending. Two epoxy formulations were used as adhesive and glass fiber-reinforced plastic (GFRP) plates for reinforcements. Tests with different anchorage lengths were developed to establish a relationship with load-carrying capacity. For an anchorage length approximately longer than twice the depth of the plate, failure was not located at the connection. There was reasonable agreement between the theoretical and experimental results. The former were always on the safe side, and there was better agreement in the case of laterally bonded plates. [ABSTRACT FROM AUTHOR]