Shinichiro Mori - Academia.edu (original) (raw)

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Papers by Shinichiro Mori

Journal of Japan Society of Civil Engineers, Ser. A1 (Structural Engineering & Earthquake Engineering (SE/EE))

The authors have paid attention to sand boils, which are ejected due to liquefaction, have conduc... more The authors have paid attention to sand boils, which are ejected due to liquefaction, have conducted a series of site investigation on liquefaction and have collected over 800 samples of ejected soils on liquefied sites during 13 earthquakes in Japan, the United States, the Philippines and Taiwan since the 1987 Chibaken-toho-oki earthquake. Over 800 samples are deemed appropriate for constituting a database for statistical research. This paper elucidates the limits in the gradation curves of liquefiable soil based on this database. First, examples of the curves of soils ejected during an earthquake with typical features are shown for understanding the fundamental nature of the database, as well as the entire figure of the database. Second, the peculiarity of the ejected soils is clarified by the difference between the soil ejected on reclaimed land and that on other kinds of ground in terms of the relationship between fines and clay contents, and ranges of mean grain size. Third, a ...

During the Hokkaido Nansei-Oki earthquake with a magnitude of 7.8, in Japan in 1993, extensive li... more During the Hokkaido Nansei-Oki earthquake with a magnitude of 7.8, in Japan in 1993, extensive liquefaction took place on a reclaimed land in Hakodate Port. A 26-m high, 2500 ton-capacity cement silo supported on a pile foundation with 64 pre-stressed concrete piles at the liquefied site suffered a 1/20 tilt and 90 cm differential settlement due to the damage to all the piles, so it was immediately condemned and demolished. The purpose of this paper is to clarify the mechanism of the damage by numerical analysis and to show the effect of oscillation of liquefying ground on the pile response. First, the distinctive damage to the pile foundation is revealed by a variety of detailed surveys. Subsequently, previously proposed method of two-step dynamic effective stress analysis for soil-pile-structure system using beammass-spring model is mentioned with parameter determination for an actual model. The total stress analyses are compared with the effective stress ones. The contribution of...

Journal of Japan Society of Civil Engineers, Ser. A1 (Structural Engineering ^|^ Earthquake Engineering (SE/EE)), 2013

Doboku Gakkai Ronbunshu, 2002

Soils and Foundations, 2015

Nepal was hit by the M7.8 Gorkha earthquake on April 25, 2015, which was the largest earthquake i... more Nepal was hit by the M7.8 Gorkha earthquake on April 25, 2015, which was the largest earthquake in Nepal's history since 1934. The recent report presented by the Government of Nepal indicates that the recorded death toll has reached about 8800. Following the earthquake, the Japanese Geotechnical Society (JGS), Asian Technical Committee of ISSMGE on Geotechnical Natural Hazards (ATC3), Japan Society of Civil Engineers (JSCE) and Japan Association for Earthquake Engineering (JAEE) decided to jointly dispatch a survey team to Nepal to conduct a reconnaissance survey of the major damage caused by the earthquake. This report summarizes the results of the survey of the geotechnical and structural damage in the Kathmandu valley, which were observed by the survey sub-team between May 1 and 8, 2015. Geotechnical and geological characteristics of a deep soil profile up to 600 m and a shallow profile up to 30 m are also described with the help of the database system established by Bhandary et al. (2012). In order to study the correlation between building damage ratios and the predominant period of ground vibration, a partial exhaustive type survey was conducted along NS line where microtremor measurements had been previously conducted in 2008. The predominant period of ground vibration was short at the ridge of the valley and long at its center, ranging from 1.2 to 4.5 s. A total of 532 buildings were assessed and more than 90% were classified as "No damage" or "Negligible to slight Damage" (Grade 0 and Grade 1), whereas only 5% of buildings were assessed as "Substantial to heavy damage" to "Destruction" (Grade 3 to Grade 5). Five locations were identified where the soil had liquefied. Liquefaction-induced damage to structures at these locations was not found, except at Nepal Engineering College where minor settlement of the college building was observed. During the 1934 earthquake, foundation liquefaction was observed in Tundhikhel area, but in the 2015 earthquake no evidence of liquefaction was detected in this area. The Kathmandu-Bhaktapur Road of Araniko Highway was heavily damaged in the Lokanthali area. The subsidence of soft soils and their lateral spreading in this area may have exacerbated the damage to this road.

Journal of Japan Society of Civil Engineers, Ser. A1 (Structural Engineering & Earthquake Engineering (SE/EE)), 2010

This paper demonstrates the changes of natural frequencies and modes of a PC bridge with a skew a... more This paper demonstrates the changes of natural frequencies and modes of a PC bridge with a skew angle of 30 degrees throughout all the construction stages from production of a PC box-beam at factory to completion of asphalt pavement work by using a portable vibration measurement system with hammering excitation. This paper clarifies as follows: The first mode of vibration and first predominant frequencies of 14 individual PC beams are closed to the first natural frequency and mode of a simply supported beam. The bridge behaves as a plate after shear key development followed by transverse post-tensioning for integration of single beams. We experimentally confirmed that its first natural mode is longitudinally bending and its second mode is torsional. The largest increase of the first natural frequency occurred after integration, however remarkable decrease observed after asphalt pavement.