Journal of Japan Society of Civil Engineers, Ser. A1 (Structural Engineering & Earthquake Engineering (SE/EE))
Online ISSN : 2185-4653
ISSN-L : 2185-4653
Volume 75 , Issue 4
Showing 1-50 articles out of 70 articles from the selected issue
JSCE Journal of Earthquake Engineering, Vol.38 (Paper)
  • Yasuko KUWATA, Yu YAMAMURA
    2019 Volume 75 Issue 4 Pages I_1-I_9
    Published: 2019
    Released: September 24, 2019
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     The earthquake occurred in the northern Osaka on Monday morning, June 18, 2018 affected many commuting workers and students. Some railways resumed operation in the afternoon of the day, but the railway system in Kansai region was disturbed all the day due to the driving suspension and thinning out operation. In this paper, we conducted a questionnaire survey on the behavior on the day of the earthquake to students of Kobe University and tried to grasp the actual condition of returning home. Based on our survey result about 30% of the students on the train had been locked in the train stopped between stations for more than an hour. It turned out that not only the distance to home but also the fact that home is near the epicenter is the reason for deciding on returning home on foot.

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  • Toshiyasu MIYOSHI, Takahiro KUMAGAI, Osamu KIYOMIYA, Shouichirou MATSU ...
    2019 Volume 75 Issue 4 Pages I_10-I_24
    Published: 2019
    Released: September 24, 2019
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     In recent years, the wind-power industry has been playing an important role in the renewable energy sector, and the construction of offshore facilities for wind-power generation has been drawing attentions in Japan, which is surrounded by sea. As the support structures of the facility, monopile type, jacket-type and gravity-type are mainly applied, and it is essential to ensure structural performance and stability against natural forces such as wind, wave and earthquake. Japan is one of the most earthquake-prone countries, and the evaluation of aseismic performance is very important. In this study, underwater shaking-table tests and reproducing analyses were carried out in order to evaluate the overturning stability of the offshore wind-power generation tower with gravity-type support structure under seismic load. As a result, it is found that the method evaluating dynamic overturning moment is quite effective in order to evaluate the overturning stability of the structure. In particular, it is clarified that the structure has high stability against overturning exceeding conventional design criteria and that the 2nd and 3rd order eigenmodes have a significant impact on the seismic response.

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  • Hidetaka SAOMOTO
    2019 Volume 75 Issue 4 Pages I_25-I_35
    Published: 2019
    Released: September 24, 2019
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     Slip partitioning on active faults is an infrequent slip pattern since the phenomenon always requires two fault planes placing close to each other: one for the normal/reverse fault, the other for the strike-slip fault. However, investigating the slip partitioning is important in the earthquake hazard assessment because the slip partitioning probably occurred during the 2016 Kumamoto earthquake. This paper investigates the occurrence conditions for the slip partitioning using finite element analysis with several parameters such as the fault dip angles and the compression direction of tectonic stress. On the bases of the results for 784 case studies, the following outcomes were found: (1) the simulation results derived a parameter set that highly activates slip partitionings, (2) the simulation results revealed the sensitivity of the parameters to the slip partitioning, and (3) the ratios, which are produced by the strike-slip and the reverse-slip magnitudes, mostly converge into a range between 0.8 and 0.9 with the higher values of the intensity for slip partitionings.

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  • Ryosuke INOUE, Fujikazu SAKAI, Shuichi OMINE
    2019 Volume 75 Issue 4 Pages I_36-I_50
    Published: 2019
    Released: September 24, 2019
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     According to our damage survey of rectangular-shaped water tanks and distributing reservoirs in the 2011 East Japan Earthquake, the 2016 Kumamoto Earthquake, etc., the damage caused by bulging is significantly greater than the damage caused by sloshing. However, with respect to the bulging characteristics of rectangular tanks, so far many have not been studied and there has been no clear description in the current seismic design guidelines of those tanks. In this paper, the authors picked up four typical rectangular water tanks and distribution reservoirs which were designed in recent years, and through detailed FEM analysis, clarified the bulging characteristics of natural vibration such as natural period and dynamic pressure distribution. We also conducted response analysis of those tanks for typical strong ground motions such as the JMA Kobe record during the 1995 Hyogoken-Nanbu Earthquake and the Small-Titan Nanakita record during the 2011 East Japan Earthquake, and found that there is a possibility that the dynamic pressure (“fluid-elastic pressure”) due to bulging overwhelmingly exceeds the levels of the current seismic guidelines in the case of the latter record, where the very short-period strong ground motion was dominated. This implies that we must take the bulging effects into account in the seismic design guidelines to improve the vulnerabilities of rectangular water tanks against earthquakes.

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  • Kenji KOSA, Tatsuo SASAKI, Masato TANAKA, Takashi SATO
    2019 Volume 75 Issue 4 Pages I_51-I_59
    Published: 2019
    Released: September 24, 2019
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     The tsunami experiment was conducted by using the parameters as wave height, girder position from the static water level. It was confirmed that the evaluation formula for horizontal force Fx can be proposed as the factors of wave height aH, girder position and side area of girder. The proposed equation was compared with other same type of bore wave experimental tests. The results showed that the proposed equation for the horizontal force can be equal or larger than that of the other experimental tests.

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  • Tsuneo OHSUMI, Hemanta HAZARIKA
    2019 Volume 75 Issue 4 Pages I_60-I_72
    Published: 2019
    Released: September 24, 2019
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     The Japanese Ministry of Education, Culture, Sports, Science, and Technology initiated the “Project for the Comprehensive Analysis and Evaluation of Offshore Fault Information” (The Project) in 2013. The objective of The Project is to contribute to assessment of earthquake and tsunami hazard in Japan’s seas by collecting offshore fault information. The Project collects and consolidates seismic profiling data using the latest data processing technology where offshore fault information is missing. The data are collected from various institutions that have conducted fault evaluation surveys in the seas around Japan. We reanalyzed the data and evaluated the faults using a consistent approach. The Project has reanalyzed the data of underground structures that were acquired by multiple institutions for the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) and it has analyzed offshore fault information in the area of the southern Nansei Islands. In assuming the tsunami caused by the 1771 Yaeyama earthquake was associated with a submarine landslide, the present study reconstructed the shape of the shelf area around Yaeyama Islands and calculated the seabed deformation before the submarine landslide occurred. The maximum tsunami heights in the coastal area were calculated by applying the change directly in tsunami propagation analysis. The duration of the collapse of the assumed submarine landslide, which little is known about, submarine landslide was calculated using the Newmark sliding block method. A map of the geological structure of the seabed revealed that older Paleozoic age rocks are exposed from the Paleogene rocks on the slope. We analyzed the tsunami propagation caused by landslides using duration of landslides and found that the influence of duration affects coastal maximum tsunami heights, significantly.

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  • Katsuyuki SAKASHITA, Akihito HATA
    2019 Volume 75 Issue 4 Pages I_73-I_80
    Published: 2019
    Released: September 24, 2019
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     In this paper, analytical studies on behavior of RC box culvert subjected to fault displacement are conducted. The fault is set as reverse fault which dip angle is 67.5 degree, and parametric studies about horizontal intersection angle of structure and fault are presented. As a result, intersection angle near to a right angle generates larger longitudinal axial forces, while it with an acute angle causes larger cross-section bending moments. In this papers condition, concrete and rebar stresses stay under their respective yield stress when fault displacement is 0.1m, and some concrete and rebar stresses reach yield stress when fault displacement is 0.2m.

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  • Kana KONDO, Hanbin GE, Liang-Jiu JIA
    2019 Volume 75 Issue 4 Pages I_81-I_92
    Published: 2019
    Released: September 24, 2019
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     In this study, experimental study on seismic performance of five perforated buckling-restrained braces (P-BRBs) was conducted under cyclic incremental loading, aiming to improve ductility of conventional buckling-restrained braces. Numerical simulation of the five specimens was also conducted. Effects of the slenderness ratio of the minimum cross-section part (stub column) between two neighboring holes, and the hole-spacing-to-hole-length ratio were investigated. Both out-of-plane flexural deformation and in-plate shear deformation were observed in the P-BRBs. Stable hysteretic curves were obtained and the deformation capacity was improved because of the additional in-plate shear deformation.

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  • Kenji KOSA, Akihiko HIROOKA, Shuhei TAKEDA, Masakatsu MIYAJIMA
    2019 Volume 75 Issue 4 Pages I_93-I_100
    Published: 2019
    Released: September 24, 2019
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     From 15th to 18th, April in 2018, We conducted the bridges survey due to Hualien Earthquake. In Qixingtan bridge located near the Milun fault, the girder moved to the transverse direction about 15 cm due to Earthquake load and punching shear failure by the girder pounding, was observed at the pier. The calculated resistance of punching shear is quite low, compared with applied Earthquake force. Zhongzheng bridge also located near the Milium fault, which abutment already damaged by ASR before Earthquake, also showed the severe cracks due to Earthquake load.

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  • Koji ITO, Tomohiro SASAKI, Shunichi HIGUCHI
    2019 Volume 75 Issue 4 Pages I_101-I_108
    Published: 2019
    Released: September 24, 2019
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     This paper describes the numerical results and its verification based on an three-dimensional effective stress analysis with cyclic elastoplastic constitutive model of soil, namely subloading surface model. Numerical analysis is carried out to confirm the applicability of numerical procedure considering the material non-linearity on both soils and structures, simulating the centrifuge model test of reinforced concrete pile foundation in liquefiable ground with similitude of 1/25. It is concluded that the presented numerical procedure had the possibility of predicting the inelastic response of soil-reinforced concrete structure interaction in liquefiable ground during strong earthquake.

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  • Wataru FUJIE, Miki TAGUCHI, Motoya SUZUKI, Hanbin GE
    2019 Volume 75 Issue 4 Pages I_109-I_122
    Published: 2019
    Released: September 24, 2019
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     This study is aimed at proposing an evaluation method of ductile crack initiation for stiffened box-sectional steel bridge piers using beam element analysis. Through shell element analysis and beam element analysis, the difference of strain concentration phenomenon between them is investigated. The influence of structural parameters such as plate width-thickness ratio parameter, column slenderness ratio parameter, and plate thickness on strain concentration modification coefficient is discussed. As a result, a general expression of strain concentration modification coefficient for stiffened box-sectional steel bridge piers is proposed. By applying the damage index with the proposed strain concentration modification coefficient, it is demonstrated that the beam element analysis could also evaluate ductile crack initiation with almost the same accuracy as the shell element analysis.

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  • Keigo TSUKIOKA, Seiji YAMADA, Yoshitaka MURONO
    2019 Volume 75 Issue 4 Pages I_123-I_132
    Published: 2019
    Released: September 24, 2019
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     In this research, we extended the applicability of method of Sato which is a nonlinear time history response analysis method considering both the frequency dependence of the impedance and the nonlinearity of the superstructure. Specifically, the applicability of the method of Sato is not guaranteed for such a problem that the impedance imaginary part takes a constant value in the low frequency range, so a method to improve this problem was proposed. In addition, numerical analysis considering the frequency dependence of the impedance and the nonlinearity of the superstructure is carried out for the SR model, and the influence of the reproducibility of the impedance imaginary part in the low frequency range on the nonlinear response characteristic of the superstructure was investigated. As a result, it was shown that the influence of the reproducibility of the impedance imaginary part remarkably appears when the influence of the hysteresis damping of the superstructure is relatively small.

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  • Masao YANASE, Yoshihisa MARUYAMA
    2019 Volume 75 Issue 4 Pages I_133-I_143
    Published: 2019
    Released: September 24, 2019
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     This study tries to develop a method to estimate the locations of soil liquefaction occurrences based on the covariance structure analysis and the support vector machine. The risk assessment map for soil liquefaction is illustrated, and it is compared with a map to show liquefaction evidences. To achieve the objective, the datasets of liquefaction occurrences after the 2011 off the Pacific Coast of Tohoku earthquake and the 2016 Kumamoto earthquake are employed in this study. The numerical model based on the weighted support vector machine (SVM), which considers the JMA seismic intensity, slope, and Japan Engineering Geomorphologic classification, is developed, and the accuracy is discussed comparing with the results of the previous study.

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  • Daichi HATAKEYAMA, Gaku SHOJI, Shigeru NAGATA
    2019 Volume 75 Issue 4 Pages I_144-I_169
    Published: 2019
    Released: September 24, 2019
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     In this study, we analyzed the damage of sewer buried pipes by strong ground motions and liquefaction in the past earthquakes: the 1995 Kobe earthquake, the 2004 Niigata Chuetsu earthquake, the 2007 Noto Hantou earthquake, the 2007 Niigata Chuetsu-oki earthquake, the 2008 Iwate-Miyagi Nairiku earthquake, and the 2016 Kumamoto earthquake. After we defined the damage ratio R by dividing the damage length Ld of the buried pipe length L, we revealed the characteristics of the damage ratio to the peak ground acceleration PGA, the peak ground velocity PGV, the instrumental seismic intensity IJ and the SI value as an index of the ground motion intensities from view of points of pipe types, diameter and classification of microtopography. We further analyzed the dependency of the damage ratio on the ground motion intensities and revealed the trend of damage ratio data classified by VP/VU pipe type, diameter of Φ<300 mm, and non-liquefaction.

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  • Mikihiro TERASHIMA, Gaku SHOJI, Masaru OKUTSU, Masato WAKATAKE, Iwao S ...
    2019 Volume 75 Issue 4 Pages I_170-I_188
    Published: 2019
    Released: September 24, 2019
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     The 2004 Niigataken Chuetsu earthquake, the 2007 Niigataken Chuetsu offshore earthquake and the 2016 Kumamoto earthquake caused severe damage to the telecommunication pipelines in bridge section. In this study, data set was constructed from view of points of bridge type, construction year, bridge length, micro-topography and liquefaction occurrence for the telecommunication pipelines exposed to previous seismic damage, In addition, the peak ground acceleration PGA, the peak ground velocity PGV, the value of spectral intensity SI and the instrumental seismic intensity IJ, which are indicators of the ground motion intensity, are selected and the relation between these indicators and the damage rate was revealed.

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  • Yoshiaki ARIGA
    2019 Volume 75 Issue 4 Pages I_189-I_198
    Published: 2019
    Released: September 24, 2019
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     Seismic responses of aqueduct bridge were investigated by three dimensional dynamic analysis for the purpose of improving accuracy and reliability of seismic performance verification of aqueduct bridge. In this study, two models, or a continuous model and a discontinuous model were set, and comparative analyses were made. As the results, in the continuous model, seismic stresses increased in the waterway. In the discontinuous model, the seismic stresses increased at the base of piers, but decreased in the waterway due to the stress relief by the opening and sliding of connecting surfaces. In addition, large opening displacement occurred at the connecting surfaces between waterways. In order to accurately evaluate the seismic performance of aqueduct bridge, it is necessary to quantitatively evaluate the possibility of falling of aqueducts and collapse of piers. For this purpose, an analytical evaluation based on three dimensional dynamic analysis taking the influence of discontinuous behaviors of connecting surfaces into account is necessary.

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  • Mamoru OTSUKA, Hisakazu SAKAI, Yusuke ONO
    2019 Volume 75 Issue 4 Pages I_199-I_206
    Published: 2019
    Released: September 24, 2019
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     Since a masonry stone wall is vulnerable structure to strong earthquake motion, the masonry stone walls and the turrets of the Kumamoto castle have suffered severe damages during the 2016 Kumamoto earthquakes. Although Kumamoto city has been considering some seismic reinforcements for the structures, they have not been able to confirm the effects of the countermeasures yet.

     In this study, we investigated the validation of the dynamic simulation for masonry structures by using 3D analytical code, YADE. First, we introduced a dynamic input motion system to YADE. Second, we conducted a series of shaking table tests with two types of wooden blocks. Finally, we performed the dynamic response analyses for all of the shaking table tests. As the results, the deformations and the collapsed times of all cases were in very good coincidence between the experiments and the numerical analyses. We could make the validation of the numerical code we have extended.

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  • Shota NOMOTO, Keita ABE, Hirofumi IKEMOTO, Hideaki TAKASAKI, Taisuke S ...
    2019 Volume 75 Issue 4 Pages I_207-I_217
    Published: 2019
    Released: September 24, 2019
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     In this study, a series of static tilting tests as well as dynamic shaking tests utilizing a 1/10 scale exper-imental model (height: 0.8m) of a gravity-type abutment with 8.0m high was performed in order to inves-tigate generation mechanism of seismic active earth pressure acting on the abutment body in consideration of dynamic interaction between an abutment body and back-fill. In the shaking table tests, L2 seismic waves were input to the abutment model at virgin state. It was observed from the experiments that the seismic active earth pressure generated in the shaking table tests was smaller than that generated in the tilting tests because of dynamic interaction effect. As a result from the shaking table tests in which weight of a girder positioned on the abutment body was changed, lateral seismic active earth pressure acting on the abutment body was reduced corresponding to magnitude of the girder weight because of the dynamic interaction effect between the seismic active earth pressure and inertia force acting on the abutment body.

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  • Shohei NAITO, Naokazu MONMA, Tetsuya YAMADA, Hiroyuki SHIMOMURA, Kanic ...
    2019 Volume 75 Issue 4 Pages I_218-I_237
    Published: 2019
    Released: September 24, 2019
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     It is important to detect damages immediately after the earthquake in terms of efficient disaster responses. In this point, we developed image analyzing methods by utilizing aerial photos of the foreshock and the aftershock of the 2016 Kumamoto earthquake. The image analyzing method consists of the differential analysis with digital surface models (DSM), the texture analysis, and the extraction method of blue tarps based on the region segmentation. With these methods, we extracted more than 15,000 damages of buildings caused by the Kumamoto earthquake, and compared with the visual photographic interpretation result which classified buildings with 4 damage levels. Then, we clarified that the DSM and the texture analysis are superior to detect destroyed buildings, and the extraction method of blue tarps is effective on the partially extraction of intermediate damages.

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  • Koichi MORIMOTO, Masakatsu MIYAJIMA
    2019 Volume 75 Issue 4 Pages I_238-I_249
    Published: 2019
    Released: September 24, 2019
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     In earthquake, liquefaction have caused large-scale ground deformation in the soft ground. Therefore, buried water pipelines were damaged seriously. Seismic type ductile iron pipes have never damaged because those joints have extension and contraction function, bend performance, and separation preventing performance. However, we have not clarified how pipelines behave when they were influenced by multiple ground deformation. In this study, we analyzed the behavior of pipeline composed of seismic type ductile iron pipes when the pipelines were influenced by multiple ground deformation, using ground displacement measured at the 1995 Hyogoken-Nanbu Earthquake.

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  • Yosuke MATSUMOTO, Sho SUZUKI, Yoshiaki ARIGA
    2019 Volume 75 Issue 4 Pages I_250-I_261
    Published: 2019
    Released: September 24, 2019
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     Sedimentation at dam occurs due to surface modifications and ground disasters around river. With the progress of sedimentation, flood control capacity and power generation capacity will decline. So, various researches have been made on these concerns so far. However, there are few quantitative studies in regard to the influence of sediment on seismic performance of dam. Therefore, in this study, we made 3-D dynamic analysis in order to quantitatively evaluate the influence of sediment on the seismic response of arch dam when high water level, for the purpose of establishing the seismic performance evaluation method considering the influence of sediment. As a result, it was found that the seismic stresses in the dam body tended to decrease as the sediment increased.

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  • Taiki YAMAMOTO, Nobuoto NOJIMA
    2019 Volume 75 Issue 4 Pages I_262-I_272
    Published: 2019
    Released: September 24, 2019
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     By use of energy input to structure, a new definition of strong motion duration is proposed. On this basis, dynamic effects of pulse waves have been characterized with emphasis on the impulsive effects. Strong motion records observed at KiK-net Mashiki and Nishihara Village (The 2016 Kumamoto Earthquake) have short duration at each predominant period of the velocity response spectra. In long-period range, peak velocity response is reached in extremely short time and occurs almost simultaneously regardless of the period. As a result, velocity response spectra remain high and flat in wide range of long-period. Such impulsive effects are considered to be representative of the pulse waves. Considering both amplitude and duration, dynamic effects have been compared among various records. In long-period range, impulsive effects are found to be dominant in KiK-net Mashiki, Nishiharamura, K-NET Ojiya (the 2004 Niigata-ken Chuetsu Earthquake) and JMA Kobe (the 1995 Hyogo-ken Nambu Earthquake).

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  • Keita ABE, Shouta NOMOTO, Hirofumi IKEMOTO, Hideaki TAKASAKI, Taisuke ...
    2019 Volume 75 Issue 4 Pages I_273-I_284
    Published: 2019
    Released: September 24, 2019
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     Seismic performance evaluations of old-fashioned abutments are important in railway safety to prevent settlement of the backfill due to tilting and sliding of the abutment body. Proper evaluations of deformation performance (seismic yield coefficient and residual displacement after yielding) of the abutments is required to properly evaluate the seismic performance, considering complicated interaction conditions between inertia force and seismic earth thrust acting on the abutment bodies. Therefore, we performed numerical simulations of a series of model experiments on the seismic behavior of an abutment utilizing Material Point Method, which enables us to deal with numerical analyses of the above-mentioned interaction conditions and large deformed states. In this paper, we present our results from the numerical simulations which well agreed with the experimental results, and relationship between girder-abutment body weight ratio and deformation performance at shaking with large seismic waves derived from the numerical analyses.

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  • Taiji MAZDA, Takashi NISHIMURA, Yukihide KAJITA, Masayuki NANBA, Nobuy ...
    2019 Volume 75 Issue 4 Pages I_285-I_293
    Published: 2019
    Released: September 24, 2019
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     In Japan’s expressway, even if the large scale earthquake of level 2 occurs, it is demanded that emergency vehicles be available expressway within 24 hours after the earthquake occurred. However, due to the characteristics of the earthquake motions and the effects fault displacement, it is difficult to determine the part which should be inspected immediately in the emergency check of the bridge after an earthquake. In 2017, in response to the Kumamoto earthquake that occurred in 2016, specifications for highway bridges was revised to consider active faults. In addition to the earthquake ground motions that have been considered in the conventional seismic design, it is necessary to consider the earthquake resistance of bridges considering fault displacements. In this study, the influence of fault displacements on the safety of bridges are investigated by examining the response of bridges when the ground earthquake fault occurs to bridges near the fault zone.

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  • Hisashi NAKAO, Shuta MIYATA, Michio OHSUMI
    2019 Volume 75 Issue 4 Pages I_294-I_305
    Published: 2019
    Released: September 24, 2019
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     In seismic design of bridges, the member is designed so as not to reach the limit state 3 against the design earthquake ground motions. When the excess action generate, the bridge may be reached the fatal damage due to the failure horizontal resistance force of members. The limit state 3 is based on the horizontal limit load carrying capacity but it doesn’t match the vertical limit load carrying capacity. Therefore, the bridge isn’t always reached the collapse immediately after reaching limit state 3.

     This study evaluated the load carrying ability and the energy absorption ability of RC column reached the limit state 3 due to the excess action.

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  • Tatsuya DOI, Naoyuki OSHIDA, Keigo TSUKIOKA, Seiji YAMADA, Yoshitaka M ...
    2019 Volume 75 Issue 4 Pages I_306-I_315
    Published: 2019
    Released: September 24, 2019
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     The authors have proposed foundation composed of micropiles and soilbags as a new foundation type. The foundation is characterized by laying soilbags on the pile heads and constructing structures on the soilbags. The expected effects are omitting junction structures of piles and footing, reducing diameter of piles, and reducing response acceleration of structures.

     This paper presents a series of cyclic loading tests targeting model piers varying number of soilbag-layers, diameter of piles and pile spacing, and size of soilbags to investigate the effects of these conditions on force displacement relationship of model piers. It is found that bending stress intensity of piles become large with small numbers of soilbag layers or small size of soilbags, although there is no significant difference in bearing capacity. It is also found that the diameter of piles and the pile spacing have a small effect on bending stress intensity of piles on the condition that total cross-sectional area of piles is constant, compared to the number of soilbag layers or the size of soilbags.

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  • Satoshi TAMAIZUMI, Kyohei UEDA, Ryosuke UZUOKA
    2019 Volume 75 Issue 4 Pages I_316-I_325
    Published: 2019
    Released: September 24, 2019
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     Lateral flow is a phenomenon caused by liquefaction of sandy layers due to vibratory loading, such as earthquakes. In order to investigate the effect of the fines content on delayed lateral flow, a two-layered, and 10 degree-inclined sandy ground was selected as a study case in this paper; the lower layer (i.e., sandy layer) was made up of silica sand No. 6, and the upper layer (i.e., silty layer) composed of a mixture of silica sand No. 8 and No. 9. Four centrifuge model tests in a rigid box were conducted in order to simulate the stagnation of excess pore water pressure (EPWP) immediately below the low water permeability layer (i.e., upper layer) during shaking, and the subsequent occurrence of lateral flow due to the redistribution of EPWP after shaking. One of these tests was made of uniform material ground (i.e., upper and lower layers were made of silica sand No. 6), and the others were composed of two layers by varying the fines content (FC=17%, 22%, 27%) in the upper layer. It is important to mention that no displacements after shaking were recorded in the uniform ground condition. In contrast, the other three tests showed the occurrence of delayed lateral flow of the upper layer which was thought to be caused by a decrease in the shear strength of the sandy layer due to the redistribution of EPWP. Also, the maximum displacement was observed after shaking when the minimum fines content was used.

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  • Masaho YOSHIDA, Taiga KATSUMI, Kouta INAMI, Hajime KAWASAKI, Ryo HASHI ...
    2019 Volume 75 Issue 4 Pages I_326-I_332
    Published: 2019
    Released: September 24, 2019
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     Small scale shaking table tests in a 1-g gravity field were carried out to evaluate effectiveness of a deformation mitigation method for new and existing road embankment during liquefaction by using geosynthetics sandwiched between gravel layer and a gabion. The reinforced gravel layer could dissipate an excess pore water pressure during liquefaction immediately, and perform as a rigid plate below the embankment. Furthermore, the gabion could confine the slope of embankment and restrain the lateral movement of slope. As a result, these functions could restrain the deformation of embankment, and keep the shape of embankment and flatness of crest.

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  • Yan LIU, Hanbin GE, Lan KANG
    2019 Volume 75 Issue 4 Pages I_333-I_344
    Published: 2019
    Released: September 24, 2019
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     Fracture of beam-column connection or partial penetration welded section of steel structures was observed in the past strong earthquakes, where combined shear and tensile stresses are applied. However, studies on the ductile fracture under such complicated stresses are limited. In this study, experiments were carried out to reveal the ductile fracture properties of structural steels under the combined stresses. A new ductile fracture criterion to simulate ductile cracks of structural steels under low stress triaxiality, which was based on the VG model, was proposed. As a result, the ductile fracture behavior of structural steels under low stress triaxiality can be accurately predicted.

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  • Soichiro YOSHIDA, Hanbin GE, Liang-Jiu JIA
    2019 Volume 75 Issue 4 Pages I_345-I_356
    Published: 2019
    Released: September 24, 2019
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     This study aims to establish an evaluation method to predict crack initiation and propagation of structural steels till rupture. In this paper, an experimental study on ultra-low cycle fatigue (ULCF) behavior of structural steels under cyclic combined axial and flexural loading was conducted. Effects of the notch shape, notch size and loading history on the crack initiation and propagation behaviors under cyclic loading was investigated. In addition, a proposed three-stage, two-parameter ductile fracture model was employed and numerical fracture simulation was conducted on the experiment specimens. Validities of the model parameter calibration method and the fracture model were discussed through comparisons of the experimental and numerical results.

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  • Hiroshige UNO, Takeshi HIROSE, Nobuyuki NAITO, Takayuki IGARASHI, Masa ...
    2019 Volume 75 Issue 4 Pages I_357-I_372
    Published: 2019
    Released: September 24, 2019
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     This study summarized the idea to improve seismic performance of middle-size bridges installing additional rubber bearings with pre-share deformation on both abutments, which called “Pre-Shear Deformation System”. In general, seismic performance of abutment in the back-filling direction is more redundant than in the front direction (bridge direction), because the seismic resistant by back-filling earth structure can be expected. Therefore, seismic performance of bridges expects to improve if pre-stressed force is installed by rubber bearings with pre-share deformation in the back-filling direction. In this study, this system is adapted to the existing 2-span continuous steel girder bridge and case studies on dynamic analysis are conducted under Level 2 earthquake. As a result, seismic performance of the bridge can be most effectively improved using Lead Rubber Bearing (LRB), although seismic performance of abutments in the back-filling direction can’t meet the required specification. In addition, it is also found that seismic performance of the bridge using this system is greatly affected by the characteristic of the back-filling soils.

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  • Hayato NISHIKAWA, Toshikazu IKEMOTO, Masakatsu MIYAJIMA
    2019 Volume 75 Issue 4 Pages I_373-I_382
    Published: 2019
    Released: September 24, 2019
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     In this study, we investigated the influence of site amplification effect and source spectra on amplification of seismic intensity for the purpose of obtaining basic information for accurately evaluating the amplification of seismic intensity (dI). Firstly, an evaluation formula for dI was obtained based on the relation between earthquake motion spectrum and amplification factor of earthquake motion index. Using the obtained evaluation formula, dI for three earthquake types, various magnitudes, fmax, site amplification effects was estimated. As a result of investigating the relationship between the fundamental peak frequency of site amplification effects and dI, the frequency of maximum dI was shifted to the lower frequency range as magnitude increased for all earthquake types. In all earthquake types, dI tended to converge to a certain value as magnitude increased.

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  • Hayato NISHIKAWA, Tatsuya NOGUCHI, Isamu NISHIMURA, Masakatsu MIYAJIMA ...
    2019 Volume 75 Issue 4 Pages I_383-I_390
    Published: 2019
    Released: September 24, 2019
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     We propose a method to directly evaluate the maximum response deformation angle of wooden building without estimating earthquake ground motion at the point where seismic observation is not set. First, the evaluation formula of the maximum response deformation angle was derived based on the relationship between the equivalent performance acceleration response spectrum and the acceleration response spectrum. Subsequently, the valuation formula consists of the closest distance of the fault and the natural frequency of the microtremor H/V was obtained by regression analysis using the earthquake motion records obtained in the 2016 central Tottori earthquake. As a result, the maximum response deformation angle can be calculated from the earthquake observation record corresponded well with the value calculated from the proposed formula.

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  • Keita UEMURA, Yoshikazu TAKAHASHI, Hiroki NAGASAKI
    2019 Volume 75 Issue 4 Pages I_391-I_407
    Published: 2019
    Released: September 24, 2019
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     The rocker piers with the mesnager hinges are known to become unstable when large displacement occurs, and it is necessary to secure the stability in the horizontal and vertical directions. Therefore, in this research, a unbonded bar reinforced concrete reinforcement (UBRC reinforcement) for rocker piers was proposed, and the effect of improving seismic performance was examined by cyclic loading test. As a result, it was found that resistance moment was increased by UBRC reinforcement and stability of the rocker piers in the horizontal direction was secured. Moreover, the experimental results of the test specimens could be reproduced in the static analysis of the cyclic loading test, and UBRC reinforcement was found to improve dynamic response characteristics of rocker piers in dynamic analysis.

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  • Akihiro TOYOOKA, Hirokazu NUNOKAWA, Meguru ONODERA, Yoshitaka MURONO
    2019 Volume 75 Issue 4 Pages I_408-I_415
    Published: 2019
    Released: September 24, 2019
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     This paper investigated the nonlinear behavior of the viaduct column equipped with a new “Collapse Direction Control Device,” or CDC device. The proposed device is used to control the direction of the final collapse of a viaduct to the designated way, by which the residential areas and/or yard for repair would be secured. In this research, series of cyclic loading tests were conducted for a RC column model where the CDC device was embedded on one side. The force-displacement relation and corresponding damage of the column according to the arrangement of the CDC device were investigated. It was found that the CDC device made the shear length of the column shorter, and corresponding reacting forces increased by 20 to 45%. It follows that the CDC device introduced the asymmetric behavior required to artificially control the direction of collapse.

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  • Yuki TANAKA, Hiroyuki GOTO, Sumio SAWADA
    2019 Volume 75 Issue 4 Pages I_416-I_425
    Published: 2019
    Released: September 24, 2019
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     Understanding ground motion amplification in a soil profile with complex basement is important in designing the input ground motions. This study focuses on the existence of a vibration mode which relates to the vibration of the ground as a single body to understand the effect of complex soil profile on earthquake ground motions. The three-dimensional numerical analysis of a narrow sedimentary basin shows the existence of a dominant frequency which is consistent at all points irrespective of the thickness of the underlying sedimentary layer. Based on the difference of transfer function values at the dominant frequency, it is determined that the basin vibrates as a single body with a fundamental mode. In addition, the distribution of the maximum amplitude resulting from the input pulse wave containing the dominant frequency was also explained with the fundamental mode. Thus, in this study, it is observed that the effect of soil profile on ground motion amplification can be studied by modal analysis of the ground.

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  • Takashi SATO, Kazuo KONAGAI, Takaaki IKEDA, Hiroaki NISHI
    2019 Volume 75 Issue 4 Pages I_426-I_432
    Published: 2019
    Released: September 24, 2019
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     To assess earthquake resistance of new or existing structures and predict earthquake damage to structures, it is important to properly evaluate the response of the structure at the time of the earthquake. In cold regions however, where the ground can freeze in winter, the dynamic soil-foundation interaction can change with the change in the density and stiffness of the frozen side soil. This paper examines in a quantitative manner, the influence of freezing of ground on the dynamic soil grouped piles interaction. It is shown herein that the grouped piles in the frozen ground tend to follow the motion of the ground over a wider range of frequency. Furthermore, it is shown that even when the freezing depth is much thinner than the characteristic length of piles determined by the stiffness ratio of the ground and the group pile, the pile cap stiffness at the time of freezing becomes noticeably large. It is confirmed that the freezing of the ground can greatly affect the interaction between the ground and the piles.

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  • Kazuya MAGOSHI, Masaki NAKAMURA, Masahiro HATTORI, Hideo OHISHI, Masat ...
    2019 Volume 75 Issue 4 Pages I_433-I_442
    Published: 2019
    Released: September 24, 2019
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     The earthquake occurred in the northern part of Osaka Prefecture around 7:58 on June 18, 2018. On the Hanshin Expressway, the permanent seismic observation was performed using measuring instruments installed in the structure, and many earthquakes were also observed in the earthquake. In this study, we investigated the response reproducibility by the dynamic analysis model used for the design, using the measured seismic waves.

     In the seismic response analysis in which the acceleration measured on the foundation is directly input to the lower end of the dynamic analysis model, the displacement of the other observation point can be approximated, and the validity of the analysis method was confirmed.

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  • Hiroki KATO, Nobuoto NOJIMA, Maki KOYAMA, Kouki TANAKA
    2019 Volume 75 Issue 4 Pages I_443-I_453
    Published: 2019
    Released: September 24, 2019
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     In order to support users’ response to lifeline disruption in the event of earthquake disaster, and also to promote self-help and mutual assistance of lifeline users, it is vitally important to provide lifeline information in a timely and appropriate manner. In this study, with the aim of understanding the information needs of utility lifeline, the process of newspaper articles (regional and national daily newspapers) related to physical and functional lifeline damage after the 2016 Kumamoto Earthquake occurred was analyzed using the text mining technique. First, frequent words were compiled using morphological analysis. Second, the major topics related to utility lifeline derived from SOM (Self-Organizing Map) of frequent words are shown. Thirdly, the number of articles on major topics and its appearance ratio are evaluated and compared between the regional and national newspapers. The relationship between frequency of articles and suspension ratio of lifelines was also examined. Finally, the process of the relationship between the topics of utility lifeline and related words was visualized using co-occurrence network.

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  • Keita ODA, Shozo KISHI, Masakatsu MIYAJIMA
    2019 Volume 75 Issue 4 Pages I_454-I_463
    Published: 2019
    Released: September 24, 2019
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     This study proposes a method for designing a water pipeline system against fault displacements by using earthquake-resistant ductile iron pipes (ERDIP). An ERDIP pipeline is capable of absorbing the large ground displacements that occur during severe earthquakes by movement of its joints (expansion, contraction, and deflection) and the use of a joint locking system. We conducted fault rupture testing by using earthquake resistant ductile iron pipe (ERDIP) and simulation analysis of pipeline behavior. We found that ERDIP is capable of absorbing fault displacement with flexible joint performance, exhibiting desirable extension, contraction and deflection. We also confirmed that the analysis method was valid by comparing the theoretical and experimental data. Using this analysis method we performed simulation of large pipeline behavior and verified the effectiveness of pipeline design using a long collar with a large extension for protection against larger fault displacements. In addition, we established a novel pipeline design method that allows for the random appearance of a fault.

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  • Yuma MORISAKI, Makoto FUJIU, Junichi TAKAYAMA, Kiyoko YANAGIHARA, Tats ...
    2019 Volume 75 Issue 4 Pages I_464-I_475
    Published: 2019
    Released: September 24, 2019
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     In past large-scale earthquake disaster, limit of public assistance and importance of mutual assistance were confirmed. On the other hand, in recent years, formulating detailed support system for vulnerable people is urgent problem during large-scale earthquake disaster. Vulnerable people are considered to need mutual assistance. Therefore, the purpose of this study is examination of actual situation about regional mutual assistance, in terms of supporter and vulnerable people. In this study, Examination of qualitative information about supporter was used questionnaire survey. And, examination of quantitative information about vulnerable people was used medical big data called National Health Insurance Data. Result of analysis, it became possible to examine the actual situation of mutual assistance in detailed by unit “town” using questionnaire survey and national health insurance data.

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  • Masahiro HATTORI, Hideo OHISHI, Yoshihisa KATO, Masaki NAKAMURA, Kazuy ...
    2019 Volume 75 Issue 4 Pages I_476-I_484
    Published: 2019
    Released: September 24, 2019
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     To investigate the accuracy of the wide network simulation for Hanshin Expressway, seismic analysis was done for the long span truss bridge with the waves observed in the northern Osaka Prefecture around 7:58 on June 18, 2018.

     As a result, the periods of analytical results at the edge and center of girder in the long span truss bridge were a little larger than those of observation results, and the main eigen period of displacement waves were reproduced by the analyses. It means the structural model is useful in the seismic response analysis for the wide network simulation.

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  • Takashi SAKAI, Yuma MORISAKI, Makoto FUJIU, Junichi TAKAYAMA, Kiyoko Y ...
    2019 Volume 75 Issue 4 Pages I_485-I_493
    Published: 2019
    Released: September 24, 2019
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     At the time of a large-scale earthquake disaster, elderly people and those with physical and mental disabilities have the problem of having a great difficulty in actions that are necessary at times of disasters such as evacuation behaviors as compared with healthy subjects. Therefore, we used the national health insurance database which is medical big data for Komatsu city in Ishikawa prefecture, and the person requiring evacuation action grasped in detail “how many people live in what kind of area” and grasped whether those people can evacuate to evacuation centers. As a result, it was revealed that the earthquake swayed more than 6 seismic intensity in the northwestern part of the central area of Komatsu city, and it was clear that there was a high possibility that about 300 evacuation support requiring persons were affected by the region depending on the region. Moreover, in the central area, there was a lot of the person requiring evacuation action who can evacuate to welfare evacuation centers beyond the capacity of welfare evacuation centers and there are many the person requiring evacuation action who can not evacuate in designated evacuation centers in the suburbs.

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  • Kyohei UEDA, Toma WADA, Ryosuke UZUOKA
    2019 Volume 75 Issue 4 Pages I_494-I_505
    Published: 2019
    Released: September 24, 2019
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     The behavior of soil-structure systems during earthquakes is commonly complicated and non-linear. One way to investigate this complex behavior is centrifuge model tests or effective stress analyses. Both techniques have been under intense investigation since 1970s, and their reliability is thought to be improving because of accumulated scientific knowledge. However, a practical process for the validation of analytical procedures has not yet been established, in particular for liquefaction phenomena, as commonly recognized among geotechnical engineering community. This may be because the validation process is conventionally carried out through a comparison with a one-time experiment and the degree of coincidence between experimental and analytical results is hard to evaluate in a quantitative way: the prediction accuracy of seismic ground response strongly depends on experimenters and analysts, and does not generally consider the variation in experimental and analytical results. To overcome the problem and improve the reliability of the prediction techniques, we carried out in this study multiple centrifuge model tests on the seismic behavior of liquefiable sloping ground, targeting a unique prototype, and subsequently performed effective stress analyses for each test result. In comparison of experimental and/or analytical results, uncertainty quantification (UQ) framework was introduced to estimate the variations and validate the computational model: an error measure called EARTH, in which a total error is given as a sum of phase, magnitude, and slope errors, was used in this study to quantify discrepancy between time histories of experimental or analysis results (e.g., response acceleration, excess pore water pressure). By directly comparing the time histories using the error measure, the variation in numerical simulations was assessed in a quantitative manner, as well as that in centrifuge experiments; this suggests that the validity of computational techniques can be evaluated in an objective way by considering both experimental and analytical variations.

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  • Kento GOTO, Keita UEMURA, Yoshikazu TAKAHASHI
    2019 Volume 75 Issue 4 Pages I_506-I_519
    Published: 2019
    Released: September 24, 2019
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     In this study, we propose a RC structure reinforced by Mesnager hinge and spiral reinforcements, and performed cyclic loading test. This structure has an insensitive structural system that keeps the uncertainty of the behavior of the column to minimum even when earthquake beyond design basis occurred. As a result, the RC column embedded with Mesnager hinge suppressed axial deformation and shear deformation of the base of column and formed a hinge structure at the base of the column even when large deformation beyond design basis occurred. Hence, it was found that the RC column embedded with Mesnager hinge has the structure that declines the uncertainty of the behavior because of the hinge mechanism of Mesnager hinge as the damage of the column become serious. Therefore, it is possible to predict the behavior of columns, and this structure can be said to be one approach toward improving anti-catastrophe.

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  • Hirokazu NUNOKAWA, Akihiro TOYOOKA, Meguru ONODERA, Yoshitaka MURONO
    2019 Volume 75 Issue 4 Pages I_520-I_528
    Published: 2019
    Released: September 24, 2019
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     Realization of a structure that is excellent in crisis resistance is required so that the structure does not lead to catastrophic damage to earthquake motions exceeding the earthquake ground motion assumed by seismic design. To this end, development of a collapse direction control device that guides the collapse direction of a structure in a designated direction is under way. In this paper, analysis of cyclic loading tests with and without a device was performed by FEM, and the consistency with the test and the stress state of the column cross section were evaluated. As a result, the stress of the column increased due to contact with the device, resulting in asymmetry in the reacting force according to with and without device. In addition, it was verified that the acting moment and shear force of the column at bottom decreased, because they were dissipated into the upper area of the column, It followed that a wider area of column reacted against horizontal force that increased the bending moment capacity. bending resistance is generated to the upper portion of the pillar where the action of the moment is small, Leading to increased yield strength.

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  • Masumitsu KUSE, Nobuoto NOJIMA
    2019 Volume 75 Issue 4 Pages I_529-I_540
    Published: 2019
    Released: September 24, 2019
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     The waveform extraction method has been proposed by use of feature vectors of earthquake ground motion characteristics. The feature vectors are composed of the 98-dimensional vector representing the temporal characteristics based on Husid plot and the 101-dimensional vector representing the amplitude and frequency contents in terms of velocity response spectra. In this study, dissimilarity of a pair of waveforms is evaluated as Euclidean distance using the 98-dimentional feature vector and weighted Euclidean distance using the 101-dimensional feature vector. The criterion for extraction of similar waveform is minimization of dissimilarity. As numerical examples, the acceleration records observed from the 2011 Off the Pacific Coast of Tohoku Earthquake are used. It has been shown that similar waveforms can be extracted on the basis of dissimilarity among arbitrary acceleration records.

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  • Hitoshi YATSUMOTO, Yasuo SAWAMURA, Makoto KIMURA
    2019 Volume 75 Issue 4 Pages I_541-I_553
    Published: 2019
    Released: September 24, 2019
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     In recent years, structures with enlarged sectional dimensions (the purpose of which in box culverts for road is to optimize the internal space) have become common. However, the seismic behavior and seismic strength of such large box culverts (BCs) is unknown. In this study, we verify the seismic behaviors of BCs and evaluate the damage to BCs using numerical analysis. The subject of this evaluation for the damage is not only the BC lining but also the surface of the embankment, because the roads are often constructed on the embankment and those roads are as important structure as BCs.

     From the results of numerical analysis, the damage to the lining and the deformation on the embankment surface are generated in the case with a shallow burden and square cross section with light degree of damage. In other cases, there is no damage to the lining, and the deformation on the embankment surface is slight; however, this deformation does not influence the vehicle's driving.

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  • Alessandra Mayumi NAKATA, Hikaru TOMITA, Kazuo KONAGAI, Masataka SHIGA ...
    2019 Volume 75 Issue 4 Pages I_554-I_561
    Published: 2019
    Released: September 24, 2019
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     We adopt a depth-integrated particle method to analyze overall features of multiple landslides along Trishuli River, Nepal, which area was devastated by the Gorkha Earthquake, April 25, 2015. Considering the difficulty in obtaining material properties of weathered matters of metamorphic rock accumulated along gorges on valley walls, the number of material parameters used in this evaluation procedure is limited as small as possible; the initial failure slope angle, if, Manning coefficient, n, for the flowing soil-water mixture, the angle of repose, id, at which the mixture on its depositional area stops spreading, and the rain concentration, RC, an index to describe rain-water collectivity of gulleys. We applied the procedure to our target area along the canyon of Trishuli River, Nepal. The result from this study indicates that weathered matters remaining on 41-degree slopes or steeper are in the critical equilibrium, and can be detached at any time. However, even debris deposits on gentler slopes such as the one in Ramche show creeping movements, and we need to keep a vigilant eye on these slopes.

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  • Atsushi HINO, Yoshitaka MURONO, Naoyuki OSHIDA, Keigo TSUKIOKA, Hisash ...
    2019 Volume 75 Issue 4 Pages I_562-I_568
    Published: 2019
    Released: September 24, 2019
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     In the case of linear structures such as railway structures, it is inevitable to construct structures on faults or in the vicinity of faults, so it is necessary to take systematic countermeasures against fault displacement. Therefore, we are studying the development process of the shear zone around the railway structure and the interaction between the ground and the structure when the surface fault displacement acts on the structure by the discrete element method. In this paper, in order to confirm the applicability of the discrete element method, relatively large scale model experiments were conducted on vertical slip faults, and the test results were reproduced and analyzed using the individual element method.

     As a result, from the numerical analysis by the DEM, it was possible to reproduce the difference of the deformation situation of the ground surface due to the presence or absence of the railway structure. We could confirm the applicability of this method to slip fault. We plan to deepen the study on vertical slip fault using this method in the future.

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