Kobori Research Complex Inc.

Japan

Kobori Research Complex Inc.

Japan
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Okano H.,Kobori Research Complex Inc. | Kato K.,Kobori Research Complex Inc. | Morikawa A.,Kobori Research Complex Inc.
Journal of Structural and Construction Engineering | Year: 2012

Considerable differences are sometimes observed among the response spectra of ground motions synthesized by fault model under the same fault parameters. The causes of variation of response spectra are classified into two factors. The one is the random nature of fault rupture process, and the other is problem issued from synthesis method itself. The variation caused by latter factor is undesirable in practical use. This paper presents the method for the direct evaluation of average response spectrum by stochastic Green's function method. In the proposed method, the element earthquake motion is not transformed into time domain using random phase, and the average response spectrum of target large fault is directly evaluated in frequency domain. The average response speclrum can be evaluated without variation because the present method does not include any random factor. The verification tests are carried out using homogeneous fault and the fault consisting of asperity and background region. The average response spectra evaluated by the proposed method agree well with the median of the response spectra of earthquake ground motions synthesized by the ordinal waveform synthesis method.


Watanabe T.,Kobori Research Complex Inc. | Kato K.,Kobori Research Complex Inc. | Nagano M.,Tokyo University of Science
AIJ Journal of Technology and Design | Year: 2016

This paper describes the influence of the accretionary wedge (hereafter AW) along the Nankai Trough on long-period ground motions in the Chukyo area using the finite difference method. Simulations with AW agree generally well with the observed records in the foreshock occurred in south-east off Mie Prefecture in 2004. Simulations without AW show larger amplitude than the observed records. Based on separation with a barrier, the difference of seismic waves between with and without AW is larger in shallow part of subsurface structures. It's revealed that AW traps seismic waves from the foreshock and hardly influences on the seismic waves from assumed strong motion generation areas.


Ogasawara S.,Kobori Research Complex Inc. | Saka T.,Kajima Technical Research Institute | Suzuki Y.,Kobori Research Complex Inc. | Koshika N.,Kobori Research Complex Inc.
Journal of Structural and Construction Engineering | Year: 2016

This paper proposes an estimation method of the impact force acting on ceiling safety nets m consideration of the Stance between ceiling and safety nets. The proposed method utilizes the balance of the potential energy of the falhng objects mcludmg ceiling boards and the stram energy stored m safety nets or wrre ropes after therr deformation, m order to obtain the magnum displacement of the safety nets or wrre ropes. The nnpact force can be estimated as the vertical force by adapting the magnum displacement on the relation of the vertical force and the displacement. The structures targeted by the proposed method can be categorized into two types: 1) safety netsor wire ropes solely lying in one way and 2) safety nets and wire ropes which interact with each other in two dimensions. The collapse patterns of ceiling considered m this paper are the one that can be treated as concentrated load and the one that can be treated as uniformly distributed load. Due to the difficulty originating from the geometrical nonlmearity the force-displacement relation of the distributed load is obtained by finite element analyses, whereas that of the concentrated load is obtained by theory The proposed method is applied to some examples to confirm the influence of the distance between ceiling and safety nets on the nnpact force. It is concluded by these examples that the distance between ceiling and safety nets seriously affects the impact force and should be considered in estimation.


Hatada T.,Kajima Technical Research Institute | Katamura R.,Kajima Technical Research Institute | Hagiwara H.,Kajima Technical Research Institute | Takahashi M.,Kobori Research Complex Inc. | And 2 more authors.
Journal of Structural and Construction Engineering | Year: 2013

This study presents the verification of damage evaluation method based on the measurement of Relative Story Displacements (RSDs). The damage evaluation method is formulated to detect the damaged locations of structural elements and evaluate their damage degree based on the displacement loading analysis by the time histories of measured RSDs. In the evaluation process, the analytical technique is introduced to compensate for the measurement errors associated with the sensor properties. The monitoring accuraciesare analyzed through the shaking table test of a full-scale 4-sotry steel building carried out at E-defense in Japan. The results indicate the effectiveness of the proposed damage evaluation method in its applications to the structural health monitoring system.


Watanabe T.,Kobori Research Complex Inc. | Kato K.,Kobori Research Complex Inc. | Tateishi H.,Tateishi Structural Design Inc
AIJ Journal of Technology and Design | Year: 2014

This paper describes applicability of a dynamic analysis model for Nikko-zan Rin-noji temple Hondo, the traditional wooden structure, based on observed records during the 2011 off the Pacific coast of Tohoku earthquake and its aftershocks. The 3-D frame model is configured on the basis of element experiments and empirical equations on earthquake resisting parts. The first natural frequency and the first damping factor of the model show relatively good agreement with those of the observed records, adding the hysteresis damping factor to the viscous damping factor even in small deformation.


Okano H.,Kobori Research Complex Inc. | Sako Y.,Kobori Research Complex Inc.
AIJ Journal of Technology and Design | Year: 2013

A simple evaluation method for amplification of response spectrum by surface strata is proposed. The proposed method does not require any time history of design ground motion. That means the proposed method can be utilized in response and limit capacity calculation. In the proposed method, the response spectrum of design ground motion is converted to equivalent power spectrum density. The transfer function of surface strata is evaluated by one dimensional elastic wave propagation theory. The power spectrum density at ground surface is converted to response spectrum using peak factor. The good accuracy is achieved in evaluation of response spectrum amplification.


Yamazoe M.,Kobori Research Complex Inc. | Maeda M.,Tohoku University | Okano H.,Kobori Research Complex Inc.
Journal of Structural and Construction Engineering | Year: 2015

This study examines the equivalent linearization analysis by a sway model which expresses a superstructure on pile foundations considering of the nonlinearity of a soil-pile system, and we propose the seismic evaluation method based on the above analysis. This seismic evaluation method consists of the decision of the failure mode of a superstructure and a pile foundation using the curve of relation of the ductility factor between a superstructure and a pile head, the evaluation of the ductility factor of a superstructure and a pile head by the equivalent linearization analysis, and the decision of the necessity of seismic reinforcement based on the result. In addition to this method, we propose another method consisting of the individual evaluation of the ductility factor without using the sway model. The proposed method is applied to a building which was damaged to pile foundations during the 2011 off the Pacific Coast of Tohoku Earthquake, and the validity of the method is confirmed by this examination.


Kusaka A.,Kobori Research Complex Inc. | Okano H.,Kobori Research Complex Inc. | Nakashima M.,Kyoto University
Journal of Structural and Construction Engineering | Year: 2015

This paper is an extension of the previous work that proposed formulation for applying Bayesian updating for post-earthquake inspection of steel frames in which beam-to-column connections are potentially fractured. A new model is proposed so that it can take into consideration the correlation of errors in estimating the safety margin. Its feature is summarized as: (1) beam-to-column connections are configured into some groups, (2) the average error is divided into that related to the entire building and that peculiar to each group, and (3) Bayesian updating is applied only for that with the whole building and that with the group to which the inspected beam-to-column connection belongs. In addition of the formulation, illustrative examples show that by applying the proposed model, priority of connection in the inspection order can alter as the results of prior inspection and that the same conclusion on the probability of occurrence of hidden failure can be lead with a fewer number of inspection locations. © 2015, Architectural Institute of Japan. All rights reserved.


Kusaka A.,Kobori Research Complex Inc. | Okano H.,Kobori Research Complex Inc. | Nakashima M.,Kyoto University
Journal of Structural and Construction Engineering | Year: 2014

This study proposes a formulation for applying Bayesian updating for safety inspection of steel frames suffered from strong ground motion in which beam-to-column connections are potentially fractured. In the proposed method, probability distributions of deformation demand and capacity of connections are modeled as that their variations are divided into those of the average error as whole building, and those of deviations from the average. Then, Bayesian updating is applied for the former alone. In order to use for the proposal method, the variations in demand and capacity of connections are examined. For demand, MCS (Monte Carlo simulation) for time history analysis shows that the variation of the maximum rotation at beam-to-column connections is estimated to be 12 to 14% as logarithm standard deviation. For capacity, about 20 % as logarithm standard deviation is statistically estimated from past structural tests for cumulative plastic deformation ratio. Finally, an MCS for a 9-story plan frame is presented as an illustrative example to examine the accuracy of the proposed method.


Watanabe T.,Kobori Research Complex Inc. | Nagano M.,Tokyo University of Science | Kato K.,Kobori Research Complex Inc.
Journal of Structural and Construction Engineering | Year: 2014

This paper investigates the influence of earthquake locations and an accretionary wedge in the Nankai Trough area on long-period ground motions in Tokyo using the 3D finite difference method. There is not much difference in ground motions in Tokyo when earthquake sources in the Japan Trench and the Nankai Trough are hypothetically assumed to be in the same conditions (e.g. moment, depth). Considering accretionary wedge in the Nankai Trough area, response is larger above accretionary wedge and smaller in Tokyo. It's suggested that the accretionary wedge is easy to trap seismic waves and doesn't necessarily enlarge response in distant Tokyo.

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