• Earthquakes and Structures
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• 제17권6호
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• pp.577-590
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• 2019

The seismic response of structures to strong ground motions is a complex problem that has been studied for decades. However, most of current seismic regulations do not assess the potential level of damage that a structure may undergo during a strong earthquake. This will happen in spite that the design objectives for any structural system are formulated in terms of acceptable levels of damage. In this article, we analyze the expected damage in single-degree-of-freedom systems subjected to long-duration ground motions generated in soft soil sites, such as those located in the lakebed of Mexico City. An energy-based methodology is formulated, under the consideration of input energy as the basis for the evaluation process, to estimate expected damage. The results of the proposed methodology are validated with damage curves established directly with nonlinear dynamic analyses.

• Earthquakes and Structures
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• 제20권1호
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• pp.71-86
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• 2021

This paper focuses on the development and assessment of the expected damage for the rocking response of rigid anchored blocks, with irregular geometry and non-uniform mass distribution, considering the site conditions and the seismicity of Mexico City. The non-linear behavior of the restrainers is incorporated to evaluate the pure tension and tension-shear failure mechanisms. A probabilistic framework is performed covering a wide range of block sizes, slenderness ratios and eccentricities using physics-based ground motion simulation. In order to incorporate the uncertainties related to the propagation of far-field earthquakes with a significant contribution to the seismic hazard at study sites, it was simulated a set of scenarios using a stochastic summation methods of small-earthquakes records, considered as Empirical Green's Function (EGFs). As Engineering Demand Parameter (EDP), the absolute value of the maximum block rotation normalized by the body slenderness, as a function of the peak ground acceleration (PGA) is adopted. The results show that anchorages are more efficient for blocks with slenderness ratio between two and three, while slenderness above four provide a better stability when they are not restrained. Besides, there is a range of peak intensities where anchored blocks located in soft soils are less vulnerable with respect to those located in firm soils. The procedure used in here allows to take decisions about risk, reliability and resilience assessment of different types of contents, and it is easily adaptable to other seismic environments.

• 한국어류학회지
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• 제32권1호
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• pp.26-31
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• 2020

농어목(Perciformes) 갈치꼬치과(Gempylidae)에 속하는 Lepidocybium flavobrunneum 1개체(체장 910 mm)가 2016년 4월 28일 한국 제주도 해역에서 처음 채집되었다. 본 종은 등지느러미 극조가 매우 짧으며 등지느러미와 뒷지느러미 뒤쪽에 각각 6개와 5개의 토막지느러미를 가진다. 또한 꼬리자루에 강한 측융기선 1개와 그 뒤쪽에 2개의 작은 돌기가 있고, 체측에는 불규칙한 파상무늬의 측선이 구불구불하게 뻗어 있다. 이 종의 새로운 속명과 국명으로 '흑갈치꼬치속' 및 '흑갈치꼬치'를 제안한다.