Research activity information

• Dec. 2023 The 16th Japan Earthquake Engineering Symposium Excellent Presentation Award


• Oct. 2021 17th World Conference on Earthquake Engineering, 17WCEE Early Career & Student Award


• Oct. 2017 日本建築学会応用力学運営委員会, 2017年度日本建築学会大会（中国）学術講演会 応用力学運営委員会 若手優秀発表賞


• Aug. 2015 シェルと空間構造に関する夏期セミナー2015 優秀発表賞

• Dynamic Mechanical Model Identification and Seismic Response Prediction for a Full-Scale Five-Story Steel Structure with Oil Dampers

  Kunihiko NABESHIMA, Takaaki KOIKE, Naohiro NAKAMURA

  Lead, Japan Association for Earthquake Engineering, Jan. 2025, Journal of Japan Association for Earthquake Engineering, 25(2) (2)

  [Refereed]

  Scientific journal


• Frequency-independent damping models for a high-rise building with simultaneous horizontal and vertical seismic motions

  Naohiro Nakamura, Yoshihiro Mogi, Akira Ota, Kunihiko Nabeshima

  Recent seismic analyses indicate that the structural damping ratio should be considered frequency-independent, for safe and accurate estimations. In response, damping models like the Wilson–Penzien (WP) damping model, that is one of the modal damping, provide frequency independence across all modes; however, these models require considerable computational resources, especially for large-scale models. While Rayleigh damping is computationally efficient, it maintains a nearly constant damping ratio only within a limited frequency range. To address these limitations, several alternative damping models have been introduced, such as uniform (UN), causal hysteretic (CH), and extended Rayleigh (ER). We use the factor W_ξ to represent the frequency range where the damping ratio remains approximately constant, defined as the ratio of maximum to minimum frequencies (f_max/f_min), within a specified tolerance of the target damping ratio. For Rayleigh damping, W_ξ = 3.7, while the CH and ER models achieve W_ξ values greater than 20. Although the UN model achieves a high W_ξ, it demands large computational resources in the implicit analyses, commonly used for seismic response studies. In this study, we address the simultaneously inputting horizontal and vertical seismic motion into a large-scale dynamic analysis model of a high-rise building. In this analysis, horizontal, vertical, and local beam vibration modes spanning a wide frequency range appeared. Considering that these modes require the same damping ratio, damping models with W_ξ values of 50 or higher are desirable. However, this threshold considerably exceeds W_ξ values achievable with the existing models, rendering these models unsuitable for the intended application. Therefore, we propose and validate the efficiency of two new damping models (ER-W and CH19) that meet this requirement by improving existing models. Using these damping models, it is possible to analyze the horizontal and vertical modes and local vibration modes of the beam, assuming a simultaneous horizontal and vertical input to a high-rise building.

  Frontiers Media SA, Dec. 2024, Frontiers in Built Environment, 10

  [Refereed]

  Scientific journal


• Fundamental study of damping models with enhanced frequency independence in nonlinear seismic response analysis -Comparison of causality-based damping and uniform damping models-

  Akira Ota, Naohiro Nakamura, Kunihiko Nabeshima, Yoshihiro Mogi, Masafumi Kawabata

  Oct. 2024, Japan Architectural Review, Translated Paper, English

  [Refereed]

  Scientific journal


• Stiffness tracking in time domain based on poly-linear hysteresis approximation and sparse modeling

  K. Nabeshima

  Jun. 2024, Proceedings of 18th World Conference of Earthquake Engineering

  [Refereed]


• Study on frequency independent damping models for large FE analysis: part 2 numerical study of models

  Y. Mogi, N. Nakamura, A. Ota, K. Nabeshima

  Jun. 2024, Proceedings of 18th World Conference of Earthquake Engineering

  [Refereed]


• Frequency independent damping models for large scale FE analysis: part 1 damping model comparison

  N. Nakamura, Y. Mogi, A. Ota, K. Nabeshima

  Jun. 2024, Proceedings of 18th World Conference of Earthquake Engineering

  [Refereed]


• Evaluating damping effects of semi-active controlled base-isolation system under large ground motion

  H. Fujitani, M. Hashimoto, K. Nabeshima, Y. Mukai, E. Sato

  Jun. 2024, Proceedings of 18th World Conference of Earthquake Engineering

  [Refereed]


• MICROTREMOR MEASUREMENT SURVEY AND NATURAL FREQUENCY ESTIMATION IN THREE-STORY STEEL FRAME STRUCTURE HOUSE

  NISHII Yasuma, KONDO Takahito, MUKAI Yoichi, NABESHIMA Kunihiko

  In this study, the authors conducted a microtremor measurement on 15 three-story steel-frame houses and investigated their natural frequencies and damping ratios. Additionally, the authors propose a new method for estimating the natural frequencies of steel-frame houses at the newly constructed state. The proposed method is an evaluation method that does not require modeling based on structural design process, and the validity of the estimated natural frequency which was obtained using this method was verified.

  Architectural Institute of Japan, Feb. 2024, AIJ Journal of Technology and Design, 30(74) (74), 47 - 52, Japanese

  [Refereed]


• FUNDAMENTAL STUDY OF DAMPING MODELS WITH ENHANCED FREQUENCY INDEPENDENCE IN NONLINEAR SEISMIC RESPONSE ANALYSIS

  Akira OTA, Naohiro NAKAMURA, Kunihiko NABESHIMA, Yoshihiro MOGI, Masafumi KAWABATA

  Architectural Institute of Japan, Sep. 2023, Journal of Structural and Construction Engineering (Transactions of AIJ), 88(811) (811), 1348 - 1359

  [Refereed]

  Scientific journal


• Nonlinear Earthquake Response Analysis Using Causal Hysteretic Damping and Extended Rayleigh Damping

  Naohiro NAKAMURA, Kunihiko NABESHIMA, Yoshihiro MOGI, Akira OTA

  Jul. 2023, European Conferences on Structural Dynamics (2023)

  [Refereed]


• Collective identification of superstructures and dynamic soil springs considering the effects of higher modes based on the MIEC method

  Takaki TOJO, Naohiro NAKAMURA, Takuya SUZUKI, Kunihiko NABESHIMA

  Jul. 2023, European Conferences on Structural Dynamics (2023)

  [Refereed]


• Identification of Building Parameters Considering Soil-Structure Interaction Based on Observed Earthquake Records

  Hinata KITAOKA, Naohiro NAKAMURA, Kunihiko NABESHIMA

  Jul. 2023, European Conferences on Structural Dynamics (2023)

  [Refereed]


• Performance of inherent damping models in inelastic seismic analysis for tall building subject to simultaneous horizontal and vertical seismic motion

  Yoshihiro Mogi, Naohiro Nakamura, Kunihiko Nabeshima, Akira Ota

  Jun. 2023, Earthquake Engineering & Structural Dynamics

  [Refereed]

  Scientific journal


• EVALUATION OF VIBRATION CHARACTERISTICS OF RC BUILDINGS CONSIDERING DYNAMIC SOIL-STRUCTURE INTERACTION BASED ON LARGE SHAKING TABLE TEST

  Takaki TOJO, Naohiro NAKAMURA, Kunihiko NABESHIMA

  Architectural Institute of Japan, Jun. 2023, Journal of Structural and Construction Engineering (Transactions of AIJ), 88(808) (808), 920 - 931

  [Refereed]

  Scientific journal


• Damage detection based on stiffness identification in time domain for poly-linear hysteresis using sparse modeling

  Kunihiko Nabeshima

  The physical parameter identification of the dynamic mechanical model, such as stiffness identification, provides some valuable information for detecting post-earthquake damage to building structures. During an earthquake, tracking changes in stiffness on the skeleton curve can be effective. It would also be helpful as an approximate evaluation if the method could be applied to structures with arbitrary poly-linear hysteresis characteristics. However, previous research has not identified any poly-linear hysteresis characteristics in a unified formulation. This paper proposes a new stiffness identification method in the time domain for building structures with any poly-linear hysteresis characteristics using sparse modeling. The validity of the proposed method was investigated through numerical simulations and a full-scale shaking table test.

  WILEY, May 2023, EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• DEVELOPMENT OF CAPPED VISCOUS DAMPING MODEL BASED ON RESTORING-FORCE AMPLITUDE

  Yoshihiro MOGI, Naohiro NAKAMURA, Kunihiko NABESHIMA, Akira OTA

  Architectural Institute of Japan, Feb. 2023, AIJ Journal of Technology and Design, 29(71) (71), 115 - 120

  [Refereed]

  Scientific journal


• Applicability of Equivalent Linear Three-Dimensional FEM Analysis of Reactor Buildings to the Seismic Response of a Soil–Structure Interaction System

  Ichihara Y, Nakamura N, Nabeshima. K, Choi B, Nishida A

  Jul. 2022, 26th International Conference on Structural Mechanics in Reactor Technology

  [Refereed]

  International conference proceedings


• Applicability of Time Domain Transform Methods for Frequency Dependent Dynamic Stiffness

  Naohiro Nakamura, Kunihiko Nabeshima, Yoshihiro Mogi, Akira Ota

  Some types of dynamic stiffness, such as the dynamic ground stiffness used in soil-structure interaction analyses and the viscoelastic body used in vibration control systems, have strong frequency dependency. To perform seismic response analysis considering this frequency dependence and the nonlinearity of the model, the dynamic stiffness in the frequency domain must be transformed into the time domain, and a time-history nonlinear response analysis is required. Therefore, many studies on these time-domain transforms have been conducted. One of the present authors has already studied and proposed transform methods for this purpose, and some of their results were used to design new types of damping models. In the present study, the outline and characteristics of the proposed methods (A to C) for this transform are described first. Next, typical problems with strong frequency dependency (i.e., the dynamic soil stiffness, Maxwell element, viscoelastic body, Biot model, and causal hysteretic damping) were transformed into the time domain using these transform methods. The applicability of the transform methods was examined. Subsequently, the characteristics of each problem in the frequency domain and the characteristics of the obtained impulse response in the time domain were analyzed. Finally, it was confirmed that the proposed methods were applicable to all studied problems. These studies are important to understand the physical meaning of these problems, which have strong frequency dependency.

  FRONTIERS MEDIA SA, Apr. 2022, FRONTIERS IN BUILT ENVIRONMENT, 8, English

  [Refereed]

  Scientific journal


• Vibration Characteristics of Capped Viscous Damping Based on Frame Restoring-Force Amplitude

  Yoshihiro Mogi, Naohiro Nakamura, Kunihiko Nabeshima, Akira Ota

  This study investigates the performance of several capped viscous damping models which give an upper limit to the initial-stiffness-proportional damping force. The comparing capped viscous damping models are the original and newly proposed one. The original capped damping model is expected to have a certain degree of frequency insensitiveness. However, unless the damping force reaches the capped value, the damping may be simply behaving as the initial-stiffness-proportional damping, also there is no clear physical basis for setting the capping value. Conversely, it is confirmed that the newly proposed damping model improves the original model problems faced with setting the capping value and frequency insensitiveness accuracy. In this study, the discussion is primarily focused on structural engineering using a 20-story fish bone model comprising a steel and reinforced concrete, but this argument can be applied to various engineering fields such as civil and mechanical engineering. Especially, this proposed model does not have mass term damping, it may be effective for a large nonlinear analysis such as sliding/uplifting and base-isolated structure.

  Frontiers Media SA, Mar. 2022, Frontiers in Built Environment, 8, 193, English

  [Refereed]

  Scientific journal


• EXAMINATION OF APPLICABILITY OF CAUSALITY-BASED DAMPING MODEL TO DYNAMIC EXPLICIT METHOD

  Ota Akira, Nakamura Naohiro, Nabeshima Kunihiko, Mogi Yoshihiro

  The purpose of this report is to examine the applicability of a causality-based damping model in which the damping ratio is constant over a wide frequency band to the dynamic explicit method.First, we give an overview of the causality-based damping model and an overview of the dynamic explicit method that approximates the velocity term by receding difference. Furthermore, in the linear elasticity problem, numerical analysis was performed using a finite element model assuming a real scale, and the applicability was examined.

  National Committee for IUTAM, 2022, NCTAM papers, National Congress of Theoretical and Applied Mechanics, Japan, 66, 195, Japanese

  [Refereed]


• BASIC STUDY ON SEISMIC RESPNSE OF SOIL-STRUCTURE INTERACTION SYSTEM USING EQUIVALENT LINEAR THREE-DIMENSIONAL FEM ANALYSIS OF REACTOR BUILDING

  ICHIHARA Yoshitaka, NAKAMURA Naohiro, NABESHIMA Kunihiko, CHOI Byunghyun, NISHIDA Akemi

  This paper aims to evaluate the applicability of the equivalent linear analysis method for reinforced concrete, which uses frequency-independent hysteretic damping with a small computational load, to the seismic design of reactor building of the nuclear power plant. To achieve this, we performed three-dimensional FEM analyses of the soil-structure interaction system, focusing on the nonlinear and equivalent linear seismic behavior of a reactor building under an ideal soil condition. From these results, the method of equivalent analysis showed generally good correspondence with the method of the nonlinear analysis, confirming the effectiveness. Moreover, the method tended to lower the structural stiffness compared to the nonlinear analysis model. Therefore, in the evaluation of the maximum shear strain, we consider that the results were more likely to be higher than the results of nonlinear analysis.

  Architectural Institute of Japan, 2022, Journal of Structural Engineering B, 68B, 271 - 283, Japanese

  [Refereed]


• Physical parameters identification for full‐scale ten‐story reinforced concrete building with degrading tri‐linear model by modal iterative error correction method

  Takuya Uesaka, Kunihiko Nabeshima, Naohiro Nakamura, Takuya Suzuki

  To assess the post-earthquake seismic safety of buildings, it is crucial to predict seismic response, and it is necessary to set the appropriate physical parameters of the response analysis model. Numerous methods have been proposed to identify physical parameters. However, most of them are limited to linear systems, and previous researches on nonlinear systems have difficulties in practical applications. In this paper, a nonlinear response analysis model is identified for a full-scale ten-story reinforced concrete building with the degrading tri-linear stiffness model by the modal iterative error correction (MIEC) method, and the accuracy of this technique is discussed by comparing with the shaking table test.

  Corresponding, Wiley, Nov. 2021, Earthquake Engineering & Structural Dynamics, 51(1) (1), 153 - 168, English

  [Refereed]

  Scientific journal


• Explicit Overturning Limit of Rigid Block Using Triple and Pseudo-Triple Impulses Under Critical Near-Fault Ground Motions

  Sae Homma, Kunihiko Nabeshima, Izuru Takewaki

  An explicit limit for the overturning of a rigid block is derived on the input level of the triple impulse and the pseudo-triple impulse as a modified version of the triple impulse that are a substitute of a near-fault forward-directivity ground motion. The overturning behavior of the rigid block is described by applying the conservation law of angular momentum and the conservation law of mechanical energy (kinetic and potential). The initial velocity of rotation after the first impulse and the change of rotational velocity after the impact on the floor due to the movement of the rotational center are determined by using the conservation law of angular momentum. The maximum angle of rotation after the first impulse is obtained by the conservation law of mechanical energy. The change of rotational velocity after the second impulse is also characterized by the conservation law of angular momentum. The maximum angle of rotation of the rigid block after the second impulse, which is mandatory for the computation of the overturning limit, is also derived by the conservation law of mechanical energy. This allows us to prevent from computing complex non-linear time-history responses. The critical timing of the second impulse (also the third impulse timing to the second impulse) is featured by the time of impact after the first impulse. As in the case of the double impulse, the action of the second impulse just after the impact is employed as the critical timing. It is induced from the explicit expression of the critical velocity amplitude limit of the pseudo-triple impulse that its limit is slightly larger than the limit for the double impulse. Finally, it is found that, when the third impulse in the triple impulse is taken into account, the limit input velocity for the overturning of the rigid block becomes larger than that for the pseudo-triple impulse. This is because the third impulse is thought to prevent the overturning of the rigid block by giving an impact toward the inverse direction of the vibration of the rigid block.

  Frontiers Media {SA}, Aug. 2021, Frontiers in Built Environment, 7, English

  [Refereed]

  Scientific journal


• Proceedings of 17th World Conference of Earthquake Engineering

  K. Nabeshima

  Lead, Sep. 2020, Proceedings of 17th World Conference of Earthquake Engineering

  [Refereed]

  International conference proceedings


• FREQUENCY-DOMAIN STIFFNESS IDENTIFICATION BASED ON ACCELERATIONS ON SPECIFIC FLOORS IN ASYMMETRIC BUILDINGS

  NABESHIMA Kunihiko

   Recently, the business continuity plan (BCP) is becoming a leading subject in the world and is being discussed with great concern in the construction and operating process of various built environments. In response to BCP, the structural health monitoring (SHM) has drawn much attention for evaluating the status of buildings and reducing post-earthquake impacts on our society. In developing SHM, the system identification (SI) methodologies, categorized as methods for inverse problems, play a critical role and the modal SI and physical SI are two major well-known branches. The physical SI has the advantage that the stiffness and/or damping coefficients of the structural model can be recovered directly and is well suited to the design of passive control systems. This is also quite useful for the damage detection. Although the physical SI is preferred in SHM, its development is quite limited and slow due to the strict requirement on multiple measurements or the necessity of complicated mathematical manipulation. In particular, investigation on physical SI of three-dimensional (3D) building structures with stiffness or mass eccentricities are more limited.

   This paper proposes a new method of frequency-domain physical-parameter system identification of three-dimensional building structures with stiffness eccentricity, which accompany torsional vibration. The two-directional story stiffnesses in the 3D building structure are identified from the horizontal accelerations recoded at the top and first floors. The proposed method has three processes. In the first process, equations of motion in the time domain are transformed into the frequency domain. The theoretical equations to identify the j-th two-directional story stiffnesses are derived from the dynamic equilibrium of the free body above the j-th story. In the second process, the responses on non-observation floors are evaluated from the horizontal accelerations recoded at the top and first floors with low-order modal shapes. In the last process, all responses are applied to the theoretical equations and the two-directional story stiffnesses are evaluated from the identification result near low-order natural frequency. Compared to the previous approaches, the proposed method has some features and advantages, which are as follows.

   ・ The proposed method is based on Fourier analysis method and avoids complicated mathematical manipulation.

   ・ The two-directional story stiffnesses in the 3D building structure can be identified from the horizontal accelerations recorded at the top and first floors of the building.

   ・ The data with high S/N ratio, which is selected based on low-order modal information, is used for the identification and this makes the proposed method robust for noise.

   ・ The two-directional story stiffnesses for each story can be identified independently. The identification result of one story doesn't affect those of other stories.

   The proposed method is demonstrated through numerical simulations and scaled experiments. Numerical examples, including the comparison with the numerical simulation results, demonstrated that the proposed method is reliable and possesses an acceptable accuracy. It should be remarked that identification results of story stiffnesses are quite stable near the low-order natural frequency and are robust for noise. However, it should be noted that the accuracy of low-order modal shapes used for the identification highly affect that of identification results. In experiments using scaled models, although the dependences to amplitude and input direction of ground motion were slightly confirmed, the reliability and accuracy of the proposed identification method were made clear.

  Architectural Institute of Japan, Jul. 2020, Journal of Structural and Construction Engineering (Transactions of AIJ), (773) (773), 899 - 909, Japanese

  [Refereed]


• STRUCTURAL DAMAGE LOCALIZATION METHOD USING ADDITIVITY ON STORY STIFFNESS DETERIORATION DUE TO DAMAGE OF STRUCTURAL ELEMENTS

  SUZUKI Nobuya, NABESHIMA Kunihiko, FUJITA Kohei, TAKEWAKI Izuru

  After unexpected disasters such as off the Pacific coast of Tohoku earthquake (2011) and the Kumamoto earthquake (2016), structural health monitoring techniques are strongly desired to evaluate the structural state of a building immediately. In the structural health monitoring system, the system identification (SI) method plays an important role in dealing with a large amount of monitoring data. As far as the SI methods are concerned, there may exist two branches classified into a modal-parameter SI and a physical-parameter SI. The main objective of the modal parameter SI is to identify the modal quantities and damping ratios. On the other hand, in the physical-parameter SI, the story stiffnesses of the objective building are directly identified from the floor response data. In order to assess the structural state of the possibly damaged building, the physical-parameter SI method is more appropriate for the structural health monitoring compared with the modal-parameter SI method. In this paper, from the viewpoint of the development of the structural health monitoring system using the physical-parameter SI method, a new structural damage localization algorithm for frame buildings is proposed based on the additivity on story stiffness deterioration caused by structural member damages. In the additivity on story stiffness deterioration, the sensitivities of story stiffnesses to structural damages of structural members are used to identify the location of damaged structural members. The additivity on the story stiffness deterioration can be proved by the Taylor series expansion of a multi-dimensional function. Based on the additivity on the story stiffness deterioration, the story deterioration of the damaged building with multiple structural members can be estimated by the superposition of the story stiffness variation due to the structural damage in a single member. In Section 3, it is shown that the story stiffnesses of a 1-bay 2-story frame are formulated by using the moment distribution method. Since the stiffness ratio of column and beam members are included explicitly in the formulated story stiffnesses, the sensitivity of the story stiffness to the stiffness of each structural member can be derived explicitly and we can understand that the story stiffness varies even if the structural members are damaged in other stories. Therefore, in the proposed damage localization method based on the additivity assumption, the location of the damaged members can be determined by evaluating the error of estimation of the story stiffness deterioration for various combinations of story stiffness deterioration for a single damaged member. The story stiffnesses of a multi-story frame are evaluated by estimating the relationship between the story shear force and the interstory drift derived by the time-history record of floor accelerations. In order to evaluate the story stiffness reliably, it is desirable to obtain the stationary floor responses. For denoising the observed response data, the singular value decomposition using low-rank approximation is applied to the floor acceleration records. It is confirmed that the relationship between the story shear force and the interstory drift can be derived smoothly by denoising, which is important to evaluate the story stiffness. In numerical examples, both a symmetric 2-bay 5-story frame and a setback 5-story frame subjected to two different excitation scenarios such as the ground motion and the top floor forced excitation are used to investigate the validity of the proposed damage localization method in Section 4. For the practical application to possibly damaged buildings, it is assumed that the damage severities of structural members and the number of damaged members are unknown. These problems are solved by the proposed damage localization method by improving the searching algorithm based on the superposition of story stiffness variation using the additivity assumption.

  Architectural Institute of Japan, Nov. 2018, Journal of Structural and Construction Engineering (Transactions of AIJ), (753) (753), 1607 - 1616, Japanese

  [Refereed]


• Frequency-domain physical-parameter system identification of building structures with stiffness eccentricity

  Kunihiko Nabeshima, Izuru Takewaki

  A frequency-domain method of physical-parameter system identification is developed for three-dimensional building structures with stiffness eccentricity. Equations of motion in the time domain are transformed into the frequency domain. The dynamic equilibrium of the free body above the j-th story is used to identify the j-th story stiffness and damping. It is required to measure the horizontal and rotational accelerations at all stories to identify the story stiffness and damping coefficients of all stories. Compared to the previous approach using the special identification function, the limit manipulation at zero frequency is unnecessary and is robust for noise. Furthermore, it should be remarked that the quantities of eccentricities in all stories can be identified using the slopes of the functions for torsional stiffness identification in the frequency domain.

  Lead, Dec. 2017, Frontiers in Built Environment, 3

  [Refereed]

  Scientific journal


• Closed-form rocking vibration of rigid block under critical and non-critical double impulse

  Ryo Taniguchi, Kunihiko Nabeshima, Kotaro Kojima, Izuru Takewaki

  Inderscience Publishers, 2017, International Journal of Earthquake and Impact Engineering, 2(1) (1), 32 - 32, English

  [Refereed]

  Scientific journal


• EFFECT OF IN-PLANE STIFFNESS OF FLOOR ON SHARING RATIO OF LATERAL FORCE IN WOODEN POST AND BEAM STRUCTURES:－ Effect of orthogonal wall arrangement －

  NABESHIMA Kunihiko, MIZUNO Kota, ABE Ryotaro, FURUKAWA Tadatoshi

   For the structures with a flexible floor such as the wooden frame structures, the effects of the in-plane stiffness of the floor on the static and dynamic behavior of structures have been investigated so far. Among these works, several investigations are conducted on the effect of stiffness of orthogonal wall, restoring force characteristics of orthogonal wall, etc. However, there is no investigation focused on the orthogonal wall arrangement. In this paper, A new beam model which enables us to evaluate the effect of the orthogonal wall arrangement is proposed and the effect of the orthogonal wall arrangement on the sharing ratio of lateral force is discussed by using the proposed model.
   In Chapter 2, from the viewpoint of the formulation, the beam model is employed as the proposed model and the proposed model is derived from Timoshenko beam theory: the proposed model is built by interpreting the floor as the Timoshenko beam subjected to the action of the unidirectional force and the moment.
   In Chapter 3, the numerical calculation is carried out by using the proposed model, in order both to verify the effect of the orthogonal wall arrangement on the sharing ratio of lateral force and to confirm the difference of the sharing ratio of lateral force between by using allowable stress design and by using the proposed model. As a result, major findings are summarized as follows;
   1) The change of the sharing ratio of lateral force, with the difference of the orthogonal wall arrangement, is essentially due to the change of the couple moment transmitted from the orthogonal wall.
   2) The couple moment transmitted from the orthogonal wall consists of the effects of eccentricity and the in-plane deformation of the floor. The effect of the orthogonal wall arrangement appears as the constraint effect of the in-plane deformation of the floor.
   3) According to the orthogonal wall arrangement, the sharing ratio of lateral force by using allowable stress design can be evaluated to the dangerous side.

  Lead, Architectural Institute of Japan, 2017, Journal of Structural and Construction Engineering (Transactions of AIJ), 82(733) (733), 463 - 473, Japanese

  [Refereed]


• Closed-form overturning limit of rigid block under critical near-fault ground motions

  Kunihiko Nabeshima, Ryo Taniguchi, Kotaro Kojima, Izuru Takewaki

  A closed-form limit on the input level of the double impulse as a substitute of a near-fault ground motion is derived for the overturning of a rigid block. The rocking vibration of the rigid block is formulated by using the conservation law of angular momentum and the conservation law of mechanical energy. The initial rotational velocity after the first impulse and the rotational velocity after the impact are determined by the conservation law of angular momentum. The velocity change after the second impulse is also characterized by the conservation law of angular momentum. The maximum angles of rotation of the rigid block in both the clockwise and anti-clockwise directions, which are needed for the computation of the overturning limit, are derived by the conservation law of mechanical energy. This enables us to avoid the computation of complicated non-linear time-history responses. The critical timing of the second impulse to the first impulse is characterized by the time of impact after the first impulse. It is clarified that the action of the second impulse just after the impact corresponds to the critical timing. It is derived from the closed-form expression of the critical velocity amplitude limit of the double impulse that its limit is proportional to the square root of size, i.e., the scale effect.

  Lead, May 2016, Frontiers in Built Environment, 2

  [Refereed]

  Scientific journal

• 水平鉛直同時入力を受ける超高層建築物における各種減衰モデルの性能

  茂木 良宏, 中村 尚弘, 鍋島 国彦, 太田 成

  Sep. 2024, [N-OS4-2] 構造物と地盤の減衰 (2)，第67回理論応用力学講演会


• 非線形地震応答解析における振動数非依存性を高めた減衰モデルの基礎的検討

  太田 成, 中村 尚弘, 鍋島 国彦, 茂木 良宏

  Sep. 2024, [N-OS4-2] 構造物と地盤の減衰 (2)，第67回理論応用力学講演会


• Analysis of vibration characteristics based on earthquake observation records of RC collective housing

  扇谷 匠己, 中村 尚弘, 鍋島 国彦, 太田 雄介, 浮田 紳二

  Sep. 2024, Dynamics and Design Conference 2024


• ネパール山間部の農村集落における伝統的構法による組積造住居の構造調査 研究 その１エリア調査と住居の予備調査

  向井洋一, 神戸軍, 鍋島国彦, 山本直彦, 宮内杏里, スワル ラム

  Jun. 2024, 日本建築学会近畿支部研究報告集


• ARXモデルによる物理パラメータ同定を介した損傷検知に関する基礎的検討

  鍋島国彦, 向井洋一

  Jun. 2024, 日本建築学会近畿支部研究報告集


• オイルダンパーを有する実大５層鉄骨構造物の振動モデル同定および地震応答推定

  鍋島 国彦, 小池 孝明, 中村 尚弘

  Nov. 2023, 第16回日本地震工学シンポジウム（一般セッション B-7 免震・制振）


• パルス性地震動下における免震構造のセミアクティブ制御の減衰効果の評価に関する研究

  橋本 真奈, 藤谷 秀雄, 鍋島 国彦, 向井 洋一, 佐藤 栄児

  Nov. 2023, 第16回日本地震工学シンポジウム（OS1 免震・制振技術の継承と革新：レジリエントな社会を目指して）


• 実測データに基づく地盤建物連成系地震応答解析モデルの同定(その2)

  北岡 陽太, 中村 尚弘, 鍋島 国彦

  Sep. 2023, 日本建築学会大会梗概集


• Poly-linear型履歴特性を有する構造物のスパースモデリングに基づく時間領域での剛性変化追跡法

  鍋島 国彦

  Sep. 2023, 日本建築学会大会梗概集


• 最大応答復元力に基づいた頭打ち付き初期剛性比例減衰モデルの振動性状(その3) 中規模RC建築物の3次元地震応答解析による性能評価

  茂木 良宏, 中村 尚弘, 鍋島 国彦, 太田 成

  Sep. 2023, 日本建築学会大会梗概集


• RC構造物の非線形地震応答性状に及ぼす初期減衰モデルの影響

  中村 尚弘, 鍋島 国彦, 茂木 良宏, 太田 成

  Sep. 2023, 日本建築学会大会梗概集


• 実測データに基づく地盤建物連成系地震応答解析モデルの同定—Identification of Soil-structure Interaction Seismic Response Analysis Model Based on Actual Observation Data

  北岡 陽太, 中村 尚弘, 鍋島 国彦

  日本建築学会中国支部 = Chugoku Chapter, Architectureal Institute of Japan, 05 Mar. 2023, 日本建築学会中国支部研究報告集 = Proceedings of annual research meeting, Chugoku Chapter, Architectureal Institute of Japan (AIJ) / 日本建築学会中国支部 編, 46, 173 - 176, Japanese


• オイルダンパーを有する実大5層S造制振建物の振動モデル同定および簡易応答予測—Identification of physical parameters of a full-scale five-storied steel building with oil dampers

  小池 孝明, 中村 尚弘, 鍋島 国彦

  日本建築学会中国支部 = Chugoku Chapter, Architectureal Institute of Japan, 05 Mar. 2023, 日本建築学会中国支部研究報告集 = Proceedings of annual research meeting, Chugoku Chapter, Architectureal Institute of Japan (AIJ) / 日本建築学会中国支部 編, 46, 165 - 168, Japanese


• 大型振動台の実測データに基づく免震建物の振動モデルの同定—Identification of Vibration Models for Seismically Isolated Buildings Based on Large Shaking Table Measurement Data

  金﨑 英哉, 中村 尚弘, 鍋島 国彦

  日本建築学会中国支部 = Chugoku Chapter, Architectureal Institute of Japan, 05 Mar. 2023, 日本建築学会中国支部研究報告集 = Proceedings of annual research meeting, Chugoku Chapter, Architectureal Institute of Japan (AIJ) / 日本建築学会中国支部 編, 46, 169 - 172, Japanese


• 大型振動台実測データに基づくRC建物の水平・上下方向の振動特性の同定

  中村 尚弘, 浜井 勇樹, 鍋島 国彦

  Sep. 2022, 日本建築学会大会梗概集


• 大型振動台実測データに基づく鋼材ダンパーを有する制振建物の振動モデルの同定

  小池 孝明, 杉澤 将太, 中村 尚弘, 鍋島 国彦

  Sep. 2022, 日本建築学会大会梗概集


• 実測データに基づく地盤建物連成系地震応答解析モデルの同定

  北岡 陽太, 中村 尚弘, 鍋島 国彦

  Sep. 2022, 日本建築学会大会梗概集


• 最大応答復元力に基づいた頭打ち付き初期剛性比例減衰モデルの振動性状（その2） 改良キャップ減衰の性能評価

  長谷川 達也, 茂木 良宏, 太田 成, 中村 尚弘, 鍋島 国彦

  Sep. 2022, 日本建築学会大会梗概集


• 最大応答復元力に基づいた頭打ち付き初期剛性比例減衰モデルの振動性状（その1） 既往の減衰モデルの問題点と提案モデルの概要

  茂木 良宏, 中村 尚弘, 鍋島 国彦, 太田 成, 長谷川 達也

  Sep. 2022, 日本建築学会大会梗概集


• 大型震動台実測データに基づく水平・上下方向の振動特性の同定—Identification of Horizontal and Vertical Vibration Characteristics Based on Large Scale Shaking Table Measurement Data

  浜井 勇樹, 中村 尚弘, 鍋島 国彦

  06 Mar. 2022, 日本建築学会中国支部研究報告集 = Proceedings of annual research meeting, Chugoku Chapter, Architecturel Institute of Japan (AIJ) / 日本建築学会中国支部 編, 45, 247 - 250, Japanese


• 地盤建物相互作用を考慮したS造建物の静的設計と動的設計の応答比較—Comparison of Response between Static Design and Dynamic Design of Steel Buildings in Consideration of Soil-structure Interaction

  田中 智大, 中村 尚弘, 鍋島 国彦

  06 Mar. 2022, 日本建築学会中国支部研究報告集 = Proceedings of annual research meeting, Chugoku Chapter, Architecturel Institute of Japan (AIJ) / 日本建築学会中国支部 編, 45, 239 - 242, Japanese


• 大型振動台実測データに基づく鋼材ダンパーを有する制振建物の振動モデルの同定—Parameter Identification of Vibration Control Building with Steel Dampers Based on Data Obtained by Shaking Table Test

  杉澤 将太, 中村 尚弘, 鍋島 国彦

  06 Mar. 2022, 日本建築学会中国支部研究報告集 = Proceedings of annual research meeting, Chugoku Chapter, Architecturel Institute of Japan (AIJ) / 日本建築学会中国支部 編, 45, 243 - 246, Japanese


• 回転入力を考慮した実大RC造建物のシステム同定—System Identification of a Full-Scale RC Building Considering Rotational Input

  久保 一晴, 中村 尚弘, 鍋島 国彦

  06 Mar. 2022, 日本建築学会中国支部研究報告集 = Proceedings of annual research meeting, Chugoku Chapter, Architecturel Institute of Japan (AIJ) / 日本建築学会中国支部 編, 45, 235 - 238, Japanese


• 20140 捩れ振動を伴う建物の特定階の観測データを用いた周波数領域における剛性同定

  鍋島 国彦, 竹脇 出

  日本建築学会, 20 Jul. 2019, 構造I, (2019) (2019), 279 - 280, Japanese


• 20151 層剛性低下量に関する建物架構単一部材の感度情報に基づく加法性を用いた損傷同定法

  鈴木 遥也, 竹脇 出, 藤田 皓平, 鍋島 国彦

  日本建築学会, 20 Jul. 2018, 構造I, (2018) (2018), 301 - 302, Japanese


• 20157 剛性偏心を有する建物の周波数領域における物理パラメター同定

  鍋島 国彦, 竹脇 出

  日本建築学会, 20 Jul. 2018, 構造I, (2018) (2018), 313 - 314, Japanese


• 断層近傍地震動を受ける剛体の転倒限界及びロッキング応答の閉形表現

  鍋島 国彦, 谷口 亮, 小島 紘太郎, 竹脇 出

  日本建築学会, 24 Jun. 2017, 日本建築学会近畿支部研究報告集. 構造系, (57) (57), 557 - 560, Japanese

• 逆解析アプローチに基づく実大振動台実験のデータ利活用

  鍋島国彦

  第71回構造力学コロキウム「実大振動実験の意義と役割」（講演者：藤原淳;和田章;長江拓也;鈴木祥之;鍋島国彦）, Mar. 2024

  [Invited]

• Robustness Enhancement of Vibration-Controlled Structures by Damping Capacity Design Method

  藤谷 秀雄, 向井 洋一, 山邊 友一郎, 佐藤 栄児, 榎田 竜太, 伊藤 麻衣, 福井 弘久, 鍋島 国彦

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Kobe University, 01 Apr. 2022 - 31 Mar. 2025


• Damping model required for seismic design using large-scale 3D model with multi-directional input

  中村 尚弘, 鍋島 国彦

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Hiroshima University, 01 Apr. 2022 - 31 Mar. 2025


• 劣化挙動を示す建物の非線形履歴モデル同定法及び極限地震動による耐震安全性評価

  鍋島 国彦

  日本学術振興会, 科学研究費助成事業 若手研究, 若手研究, 広島大学, 01 Apr. 2022 - 31 Mar. 2025


• 実測記録に基づく建築物の振動特性に関する研究

  株式会社 長谷工コーポレーション, 共同研究, Apr. 2024


• 極限的断層近傍地震動を受ける剛体及び建物のロッキング振動と転倒限界の解明

  鍋島 国彦

  日本学術振興会, 科学研究費助成事業 特別研究員奨励費, 特別研究員奨励費, 京都大学, 26 Apr. 2017 - 31 Mar. 2019

  本年度における研究成果は，1)水平軸回りの問題である「剛体の転倒限界に関する研究」，2)鉛直軸回りの問題である「偏心を有する建物の物理パラメタ―同定」に関する研究，の2つに分けられる．以下，それぞれについて詳述する． 1) 前年度で構築した剛体の転倒限界理論の妥当性を検証するために，木製ブロックを用いた模型実験を行った．模型実験は自由振動実験と1サイクル正弦波加振実験の2段階に分けて行った．自由振動波形の周期，および回転角の各ピークとの関係から，本試験体の幅高さ方向の質量分布がほぼ一様であることを確認し，理論構築時に設けた仮定にほぼ適合することを確認した．そこで，時刻歴応答解析より得られる自由振動波形とのフィッティングから試験体の反発係数を推定し，それを用いて1サイクル正弦波加振時における転倒限界加速度振幅を推定した．1サイクル正弦波加振実験結果との比較から，提案手法により算出・補正した転倒限界加速度振幅との相対誤差は約10％～15％であることを確認した． 2) 前年度で構築した物理パラメター同定手法を二軸偏心建物に適用できるように拡張し，1階と最上階の観測データのみによる同定を可能とした．この手法では，既知情報として与えた水平方向1次のモード形に基づいて全階の水平方向1次モード応答を推定し，それらを同定に用いる応答データとしている．そのため，懸念される問題点として，近接モードの影響によるモード応答の推定誤差の増大，およびそれに伴う同定精度の低下が挙げられ，この点については今後の課題とする．構築した同定手法の精度を検証するために，入力方向と振幅レベルを実験変数として小型模型実験を行った．入力方向に対する依存性や振幅依存性が若干認められたものの，試験体の設定値に対する同定値の相対誤差は概ね10％以内に収まり，本手法が概ね良好な精度を有することを確認した．

• 労働安全衛生法による技能講習 床上操作式クレーン運転 修了

  Aug. 2019


• 労働安全衛生法による技能講習 玉掛け技能講習 修了

  Sep. 2016