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Physics of earthquakes
Published in Ömer Aydan, Earthquake Science and Engineering, 2023
A common feature of such associations between volcanoes and earthquakes are strato-volcanoes on volcanic arcs, where the upper plate ruptures to allow access to the rising magma. Interplate earthquakes that occur along the subduction zones are associated with the release of stored strain and allow more than 10 m relative slip probably causing expansive volumetric strain, which may be quite large along volcanic arcs and it may cause additional rupturing in the volcanic arc. Besides these mechanical deformations, it must be noted that the release of the stored mechanical energy would be converted to heat as explained in the next section and it is experimentally confirmed (e.g. Aydan et al. 2011, 2015). The heat production inducing high temperatures would decrease the strength of the Earth’s crust as well as cause the melting of surrounding rock.
Development of partial factor design method on bearing capacity of pile foundations for Japanese Specifications for Highway Bridges
Published in Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards, 2019
Toshiaki Nanazawa, Tetsuya Kouno, Gaku Sakashita, Kazunori Oshiro
This article reports on a study on partial factors used at the resistance side in the verification of bearing capacity of a pile foundation aiming for the introduction of the limit state design method and partial factor design method in the Japanese Specifications for Highway Bridges (JSHB) (JRA 2012). That is to say, the design equations to estimate the pile bearing capacity and those to estimate the axial spring constant are revised based on loading test results analyses, and the uncertainties relating to these design equations are quantified as a first step. As a second step, the reliability of the bearing capacity of piles that are designed by the conventional specifications is quantified. The quantification is done under the persistent situation as well as the Level 1 earthquake situation, and various other conditions of piles are also taken into account. Finally, a series of partial factors are proposed considering the differences in the pile types, installation methods, and ground soil type classifications. The persistent situation above is defined as the situation where earthquake and wind load influences are not considered in the load combination. “Level 1 earthquake situation” is the situation where the magnitude of an earthquake motion that is highly likely to occur during the design working life of a bridge is considered. There is a Level II earthquake situation where the magnitude of earthquake motion that is the maximum credible is considered (JRA 2017). Level II earthquake have two types: Type I and type II. Type I is an earthquake ground motion that represents a large-scale interplate earthquake with a low frequency of occurrence. Type II is an earthquake ground motion corresponding to a inland earthquake low probability of occurrence such as Hyogo-ken nanbu earthquake.
Seismic Retrofit of Pilotis Buildings by Novel Aluminium Buckling-Restrained Braces (Al-BRBs). Application to a Modernist Architecture Building in Lisbon
Published in International Journal of Architectural Heritage, 2023
Jorge M. Proença, Ricardo Ferreira, António Sousa Gago
The Portuguese version of Eurocode 8 considers two earthquake scenarios, seismic action type 1 (distant, high magnitude, interplate earthquake) and type 2 (near, moderate magnitude, intraplate earthquake). Given the relatively high periods of the fundamental modes, seismic action type 1 should control the design, for which reason seismic action type 2 was discarded in the subsequent stages of the study.