Details of a Researcher - Kohiyama, Masayuki

Papers - Kohiyama, Masayuki

Division display 61 - 80 of about 171 ／ All the affair displays >>

Evaluation of Seismic Retrofitting Effectiveness for District Evacuation Safety Based on Evacuees' Isolation Probability by Using Markov Chain Monte Carlo Method

Todaka, M. and Kohiyama, M.

Proc. 2nd JAEE International Symposium (Japan Association for Earthquake Engineering) 2013.11

Research paper (international conference proceedings), Joint Work

We propose a new quantitative method to evaluate the effectiveness of seismic retrofitting of houses for evacuation safety. The priority of houses that need retrofitting is evaluated on the basis of the probability of evacuees becoming isolated owing to road blockades caused by the debris of collapsed houses after an earthquake. We improve the method to extract samples by using the Markov chain Monte Carlo method. A new index is introduced to evaluate the difference of total expected numbers of isolated evacuees before and after the retrofitting.

Seismic Vibration Control of a Multi-Story Building Considering Damage Risk of Accommodated Computer Servers

Ito, T. and Kohiyama, M.

MJIIT-JUC Joint International Symposium 2013.11

Research paper (international conference proceedings), Joint Work, Accepted

The loss of a building function is one of the serious effects of seismic ground motion. We discuss the situation of computer servers in a data center and the required linear optimum control of a building to reduce the damage. We construct a model of a building that contains computer servers on a seismic isolation floor and that is equipped with an active vibration controller on the top floor. Simulated ground motions are input to the model, and the maximum responses are examined to evaluate the fragility curve of the server. Finally, we investigate design parameters of a controller which enable a reduction in damage risk of the servers placed on different floors.

LQG Design Scheme for Multiple Vibration Controllers in a Building–Equipment System Considering the Maximum Control Force

Kohiyama, M. and Yoshida, M.

the 2013 World Congress on Advances in Structural Engineering and Mechanics 1229-1236 2013.09

Research paper (international conference proceedings), Joint Work

A method to determine a control scheme and parameters is proposed for a data center facility with a vibration controller on its top floor and a secondary isolation device with its own vibration controller designed to protect delicate computer equipment. The aim is to reduce acceleration and drift from an earthquake for computer servers placed on the isolation device that must operate during a seismic event. A linear elastic model was constructed and the evaluation function of the linear quadratic Gaussian control was formulated. The relationship between control parameters and responses was examined, and it was confirmed that the proposed scheme properly defined system parameters to minimize the responses of both the building and computer server.

多分野をつなぐ性能設計

Masayuki KOHIYAMA

2013年度日本建築学会大会（北海道）構造部門（荷重）パネルディスカッション資料「建築物の性能設計・再考―想定外事象も踏まえて」 (日本建築学会) 15-20 2013.08

Research paper (conference, symposium, etc.), Single Work

設備や非構造部材の被害を低減するためには設計者・技術者間のコミュニケーションが不可欠である。人命保護などの要求性能にはサブ性能のヒエラルキーが存在しており、役割分担と協調のため、性能というコンセプトで展開される技術コミュニケーションが作り手側に求められる。また、構造設計者は、利害関係者の要望を吸い上げ、安全性能を具体化し実現するプロセスにより積極的に関わるべきである。従来の耐震設計などの性能チェックにとどまらず、多分野と連携し、居住性や事業継続性など建築主や社会のニーズに応えた建物を実現する性能設計の普及を期待する。

Optimal stiffness distribution of mid-storey-isolated buildings considering storey drift and floor acceleration response

Kohiyama, M. and Takano, K.

Earthquake Resistant Engineering Structures IX, Brebbia, C.A. and Hernández, S. eds. (9th World Conference on Earthquake Resistant Engineering Structures) (WIT Press, Southampton, UK / University of A Coruña, Spain and Wessex Institute of Technology, UK) 10 191-202 2013.07

Research paper (international conference proceedings), Joint Work

This paper formulates a response prediction formula based on complex modal superposition and frequency response functions of single-degree-of-freedom systems for both storey drift and floor acceleration of a mid-storey-isolated building under the assumption of white noise input. This study verifies that the proposed formula can estimate the seismic response of a building accurately, even if a system includes the overdamped mode, by comparing the same with the results of a time-history analysis. To support the structural design of a mid-storey-isolated building, the proposed formula is applied to an optimal design problem, which considers the objective function of acceleration response in a superstructure and constraints on storey drifts. A genetic algorithm is employed to obtain the optimal stiffness distribution and damping coefficient of the isolation layer. This study confirms that the acceleration response of the optimal design is successfully reduced, with other responses remaining within acceptable ranges.

Simultaneous optimization of structural shape and control system of large-scale space frame

Dan, M. and Kohiyama, M.

Research paper (international conference proceedings), Joint Work

In general, large-scale space frames, such as stadiums and gymnasiums, have a role as an evacuation facility. However, some accidental falls of a ceiling and equipment during an earthquake have been reported, and these accidents might cause human injury or casualty. On the other hand, these structures often have an aesthetically elaborated design, but they do not always have high performances from a structural point of view. This research proposes a method to support designing a large-scale space frame, which implements: 1) a design elaborated by an architect and 2) structural and control performances, which can reduce damage or fall of a ceiling, on the basis of simultaneous optimization of structural and control systems. The number of design parameters in the optimization problem is reduced by describing the roof shape with a Bézier surface. The genetic algorithm is used for the optimization.

Dynamic collapse analysis of four-story steel frame using E-Simulator

Miyamura, T., Ohsaki, M., Yamashita, T., Isobe, D., and Kohiyama, M.

4th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN 2013) (European Community on Computational Methods in Applied Sciences and International Association for Computational Mechanics) 12 2013.06

Research paper (international conference proceedings), Joint Work

Dynamic collapse analyses of a 4-story steel building frame modeled by solid elements are performed using the E-Simulator, which is a parallel finite element analysis software package for civil and building structures. Code verification, calculation verification, and validation of the numerical codes (V&V) are conducted by comparing the results obtained by the E-Simulator, those obtained by a beam element analysis code, and the experimental results obtained by the 3-D full-scale earthquake testing facility, the E-Defense at NIED. The seismic response analyses under 60% or 100% of the JR Takatori seismic wave of the 1995 Hyogoken-Nanbu earthquake are performed. The shear forces and interstory drift angles of the 1st story obtained by the E-Simulator simulation and the E-Defense full-scale test have good agreement. Both response of the whole frame and local deformation due to plastic buckling are simulated in the analysis using the E-Simulator.

High-precision finite-element analysis of rubber bearing for base-isolation of building structures

Ohsaki, M., Miyamura, T., Kohiyama, M., Yamashita, T., Yamamoto, M., and, Nakamura, N.

Research paper (international conference proceedings), Joint Work

Seismic response analysis is carried out for a base-isolated frame. The RC-frame members as well as the rubber bearings are discretized into hexahedral finite elements. The material properties of rubber are represented by the Ogden model, and the frame is assumed to remain in elastic range. The seismic response analysis of the frame, which has more than 3 million degrees of freedom is carried out using the E-Simulator, which is under development at E-Defense, Japan, based on a software package called ADVENTURECluster. It is shown that the global and local responses can be simultaneously evaluated through a high-precision finite element analysis.

Design Method of a Quadratic Cost Function for Vibration Control to Maintain Functions of a Building During an Earthquake

Nanako Miura and Masayuki KOHIYAMA

Journal of Structural and Construction Engineering (Transactions of AIJ) (Architectural Institute of Japan) 78 ( 687 ) 923-929 2013.05

Research paper (scientific journal), Joint Work, Accepted

It is important to maintain functions of a building such as providing medical services, performing production operations, and dwelling during and after an earthquake. Until now, vibration control devices have been devised and installed in many buildings. To maximize the control effects under the limited capacity of a control force, a method for constructing an evaluation function on the basis of the prescribed control objectives is proposed, in which the control objectives are expressed as dimensionless numbers using the required performance levels. The effectiveness of the proposed method is verified by a time-history analysis.

Access to Document (DOI)

Numerical Model of Mechanical Coupling for Interior Open Piping Considering Nonlinear Behavior

Kaoru KINOSHITA, Masayuki KOHIYAMA, Masayuki OHSAWA, and Shinobu KAWAGUCHI

Journal of Structural Engineering (Architectural Institute of Japan) 59B 119-126 2013.03

Research paper (scientific journal), Joint Work, Accepted

屋内ガス配管用機械式継手の数値解析モデルを曲げ実験・震動台実験の結果に基づき2種類構築した。まず，硬化型特性を持つバイリニアばね・線形弾性ばね複合モデルを構築した。次に，Ozdemirモデル・線形ばね・ギャップクロージングばねに基づき非線形のヒステリシス特性を持つばねを構築した。震動台実験を再現する時刻歴応答解析を行い，モデルの妥当性の評価を行ったところ，後者のモデルは応答レベルが小さい場合に良好に実験を再現することを確認した。

Shaking Table Test of Seismic Response Control of Building-Elevator System Using Vibration Control Device on the Top Floor

Keisuke WATANABE, Nanako MIURA, Masayuki KOHIYAMA, and Masaki TAKAHASHI

Journal of Structural Engineering (Architectural Institute of Japan) 59B 339-348 2013.03

Research paper (scientific journal), Joint Work, Accepted

近年報告されているエレベータロープの地震被害を低減するため、アクティブマスダンパー(AMD)や連結制振などの建物用の制振装置を用いた制御手法を提案した。提案手法は建物とロープの両方の安全確保を目標とした線形二次ガウシアン制御に基づいている。提案手法の有効性を実証するため、超高層建物の縮小モデルであるアルミ製の4層試験体を用いた実験を行った。エレベータロープは銅の薄板でモデル化し、AMDを試験体の最上層に設置した。震動台実験を行った結果、提案手法はエレベータロープの応答を低減することを確認した。

Simultaneous Optimization of Structural and Control Systems of a Multi-Story Building With PD Controlled Active Braces Using Design Response Spectra

Masayuki KOHIYAMA and Chihiro HORIGUCHI

Journal of Structural and Construction Engineering (Transactions of AIJ) (Architectural Institute of Japan) 78 ( 683 ) 71-80 2013.01

Research paper (scientific journal), Joint Work, Accepted

An optimization method is developed for the structural and control systems of a multi-story building equipped with proportional-derivative (PD) controlled active braces. The method uses design response spectra to consider ground motions and employs the complex complete quadratic combination method to estimate the maximum response and the maximum control force. Both structural and control costs are minimized under the constraints of the maximum inter-story drift and the absolute acceleration responses. The proposed method is applied to the simultaneous optimization of a three-story building with PD-controlled active braces and it is demonstrated that the method can efficiently provide Pareto optimal solutions.

Access to Document (DOI)

Evaluation Method of Seismic Safety of Interior Piping Using Single-Axis Shake-Table Test and Finite Element Analysis

Ohsawa, M., Kawaguchi, S., Atarashiya, Y., Nakakomi, A., Kinoshita, K., and Kohiyama, M.

15th World Conference on Earthquake Engineering (International Association for Earthquake Engineering) 2012.09

Research paper (international conference proceedings), Joint Work

As a first step to establishing a reliable numerical simulation model for interior city-gas piping, some cases of shake-table tests for a partial-piping specimen were conducted. Static bending tests using almost the same supporting apparatus as the shake-table test were also conducted to obtain the mechanical characteristics of the clamp, the hanging bolt and the mechanical coupling, and simplified analytical models were investigated for the non-coupling specimen and for the with-coupling specimen. Finite element analyses (FEA) were then carried out for these models. The experimental data regarding the seismic response during the shake-table tests generally agreed with the FEA results. It was therefore inferred that the major structure of the analytical models proposed in this study is adequate to evaluate seismic safety for interior city-gas piping.

Health Disturbance of Residents in Houses Tilted Due to Liquefaction during the Great East Japan Earthquake

Kohiyama, M. and Keino, C.

15th World Conference on Earthquake Engineering (International Association for Earthquake Engineering) 2012.09

Research paper (international conference proceedings), Joint Work

The 2011 off the Pacific coast of Tohoku Earthquake triggered liquefaction of soil in wide areas of Japan. In particular, a number of damaged houses were found in the land reclamation areas of the Kanto region. Some residents who lived in houses that were tilted by liquefaction complained of health disorders. We report on the results of a questionnaire survey of residents in Mihama Ward, Chiba City, about the characteristics of their houses, earthquake damage, health disturbances, and so on. Probability models of health disturbance with respect to house tilt angle due to liquefaction are constructed based on the survey data. The probability that a respondent experienced health disturbance was found to be considerably higher when the tilt angle exceeded 0.013 rad.

Comparative Study Between Centralized and Decentralized LQR Controls of a Building-Elevator System

Yoshida, M., Kohiyama, M., and Takahashi, M.

15th World Conference on Earthquake Engineering (International Association for Earthquake Engineering) 2012.09

Research paper (international conference proceedings), Joint Work

When both a building and its equipment have a vibration controller, the controller of the equipment should consider the behaviour of the building and vice versa. First, we classified control schemes according to the amount of state variables communicated between the controllers and the type of control objectives. Then, a high-rise building with an elevator system is analysed under seismic excitation to compare the performance of the classified control schemes that use a linear quadratic regulator. It is observed that the story drift and the response of the elevator rope are best reduced when all the state variables are communicated, but they can be sufficiently reduced even if not all the state variables are communicated.

Vibration Reduction of a Building-Elevator System Considering the Intensity of Earthquake Excitation

Miura, N. and Kohiyama, M.

15th World Conference on Earthquake Engineering (International Association for Earthquake Engineering) 2012.09

Research paper (international conference proceedings), Joint Work

To maximize the control effects under the limited capacity of a control force, a control method based on variable gain feedback control for a coupled model of a building and an elevator is proposed. In this method, a controller selects a proper control objective and prevents the saturation of the control force considering the intensity of the ground motion and the associated building response level. For preventing saturation, the maximum required control force is estimated on the basis of the square root of sum of squares (SRSS) method using the input ground acceleration. The effectiveness of the proposed method is verified by a time-history analysis. The analysis is performed using the long-period ground motion record of the 2011 off the Pacific coast of Tohoku Earthquake, 100 simulated waves with the peak ground velocity of about 25 cm/s2 and 300 waves obtained by scaling the simulated waves.

実践的な性能設計／地震リスクマネジメント，2011年度日本建築学会大会（北陸）構造部門（荷重）パネルディスカッション

KOHIYAMA MASAYUKI

建築雑誌 (日本建築学会) 127 ( 1635 ) 22-24 2012.09

Research paper (scientific journal), Single Work

High-precision FE-analysis for global and local elastoplastic responses of building frames

Ohsaki, M., Kohiyama, M., Miyamura, T., Yamashita, T., and Akiba, H.

International Symposium on Reliability Engineering and Risk Management 2012 (Kanagawa University, Tongji University, Central South University and the International Association of Structural Safety and Reliability) 561 - 566 2012.08

Research paper (international conference proceedings), Joint Work

Global and local responses of steel frames are simultaneously simulated using a high-precision finite element (FE) analysis considering composite beam effects. A detailed analysis is first carried out for a 4-story building frame subjected to seismic motion. The steel material is modeled using a piecewise linear isotropic-kinematic hardening that can incorporate a yield plateau. Static cyclic response analysis is then carried out for a compo-site beam supported by a column. It is demonstrated that the experimental results, which show asymmetric behaviors due to contact of the slab to the column, can be simulated accurately using the high-precision FE-analysis.

Influence of the number of samples of simulated earthquake motions on accuracy of seismic risk assessment of a two-story house

Watanabe, T. and Kohiyama, M.

Research paper (international conference proceedings), Joint Work

入力地震動数と建物地震被害リスクの精度の間の関係について，動的解析に基づく手法とハザード曲線・フラジリティ曲線に基づく手法の2つに関し分析を行った。まず，マグニチュード・震源距離・震源深さの組合せの各ケースについて，1000波の模擬地震動を作成した。次に，モンテカルロシミュレーションを行い，2階建て木造建物の地震被害を評価した。限定数の解析結果を用い，上記の2通りの手法で30年間の被害発生確率を計算した。その結果，2手法とも同数の入力波で同程度の精度となることを確認した。

Simultaneous optimization of structure and control under seismic excitation uncertainties with unified cost function

Giron, N. and Kohiyama, M.

Research paper (international conference proceedings), Joint Work

地震動を受ける鉄筋コンクリート造建物の制御と構造の同時最適化手法の提案を行った。設計変数は各層の剛性，制御装置の位置，スライディングモード制御パラメータで，目的関数であるライフサイクルコストは，初期費用，修復費用からなる。最適化には遺伝的アルゴリズムとネルダー・ミード法を用いた。入力地震動は模擬地震動を用い，非線形時刻歴応答解析により修復費用を推定した。4層建物モデルを用い，提案手法の有効性を確認した。

　 Previous page - Next page 　