Details of a Researcher - Kohiyama, Masayuki

Papers - Kohiyama, Masayuki

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Evaluation of Seismic Damage Risk of Elevator Rope in High-Rise Building Based on CCQC Method

Kohiyama, M., Kita, T., and Mitsui, A.

9th U.S. National and 10th Canadian Conference on Earthquake Engineering (Earthquake Engineering Research Institute & Canadian Association for Earthquake Engineering) 10 2010.07

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

To solve the problem of elevator rope sway in a high-rise building, the seismic damage risk of a building and suspension rope are examined using the Complex Complete Quadratic Combination method. A building site was assumed at Sinjuku, Tokyo in Japan and possible earthquake source zones were considered in Chuetsu, Niigata and the northwest of Chiba. The following findings were obtained: For the 100-, 150- and 250-meter-high buildings, the damage risk of the rope was high when an elevator car or a counterweight was in a lower floor because the rope was long to cause resonance. However, for the 50-, 100- and 200-meter-high buildings, the damage probability was the highest when in a layer other than the bottom. The distribution of the probability of rope damage varies considerably depending on the building height.

Dynamic Property Evaluations of Full-Scale 4-Story Steel Frame Using Parallel FE-Analysis

Kohiyama, M., Ohsaki, M., Miyamura, T., Onda, K., Isobe, D., Akiba, H., Hori, M., Kajiwara, K., and Ine, T.

9th U.S. National and 10th Canadian Conference on Earthquake Engineering (Earthquake Engineering Research Institute & Canadian Association for Earthquake Engineering) 9 2010.07

Research paper (international conference proceedings), Joint Work

The project of E-Simulator is under way at Hyogo Earthquake Engineering Research Center (E-Defense) of National Research Institute of Earth Science and Disaster Prevention (NIED), Japan, which facilitates the world's largest shaking table. The E-Simulator uses the parallel finite element (FE) analysis software package called ADVENTYRECluster (ADVC) as a platform. In this study, we report the results of high-precision FE-analysis for simulation of collapse behavior of the 4-story steel building frame that is the specimen of the full-scale total collapse shaking-table test conducted in September 2007 at E-Defense. It is shown that elastoplastic dynamic responses can be estimated with good accuracy using a high-precision FE-analysis without resort to macro models such as plastic hinge and composite beam effect.

Large-Scale Parallel Analysis System for Virtual Shaking Test for Steel Building Frames

Akiba, H., Ohsaki, M., Miyamura, T., Kohiyama, M., Onda, K., Isobe, D., Hori, M., Kajiwara, K., and Ine, T.

9th World Congress on Computational Mechanics and 4th Asian Pacific Congress on Computational Mechanics (WCCM/APCOM 2010) (International Association for Computational Mechanics) 308 2010.07

Research paper (international conference proceedings), Joint Work

Introduction: In structural analysis, the iterative substructuring method is a most promising framework, which is to be used on parallel computer systems. But using just the parallel processing does not allow us to obtain the desired level of performance. We need special preconditioning procedures well-suited to the iterative method and the domain decomposition method. The CGCG method [1], which will be described in some detail in this paper, gives high performance to the iterative substructuring method by a precondition technique depending on the domain decomposition. The CGCG method is implemented in a commercial code ADVENTURECluster (ADVC), and ADVC can solve dynamic nonlinear problems with more than 10 million degrees of freedom. Hyogo Earthquake Engineering Research Center (E-Defense) owns the world’s largest shaking table [2]. Also E-Defense is developing E-Simulator code which we hope to act as a virtual shaking table by fully taking advantage of recent development of high-performance computing. E-Simulator uses ADVC as a platform. The paper shows the results of a nonlinear seismic analysis of steel building frames as a test specimen of the virtual shaking table. Numerical Algorithms and Examples: The CGCG method is a fully iterative method based on the domain decomposition method, in which the decomposed subdomains are not considered as substructures, whereas the standard iterative substructuring methods take those as substructures. Recent enhancement of the preconditioning gave the method higher performance than the original CGCG method. The enhanced CGCG method and E-simulator equipped with the enhanced CGCG method are applied to solve nonlinear seismic analyses of steel building frames. Conclusions: The enhanced CGCG method is described, and the E-simulator equipped with the enhanced CGCG method is applied to analyze nonlinear seismic analyses of steel building frames, which will be examples of the virtual shaking test. References: [1] Akiba et al, Proceedings of SC06. [2] http://www.bosai.go.jp/hyogo/ehyogo/.

Large-Scale Parallel FE-Analysis for Simulation of Collapse Behavior of Steel Building Frames

Miyamura, T., Ohsaki, M., Kohiyama, M., Onda, K., Isobe, D., Akiba, H., Hori, M., Kajiwara, K., and Ine, T.

9th World Congress on Computational Mechanics and 4th Asian Pacific Congress on Computational Mechanics (WCCM/APCOM 2010) (International Association for Computational Mechanics) 308 2010.07

Research paper (international conference proceedings), Joint Work

Introduction: The project of E-Simulator is under way at Hyogo Earthquake Engineering Research Center (E-Defense) of National Research Institute of Earth Science and Disaster Prevention (NIED), Japan, which facilitates the world's largest shaking table (Hori et al. 2007).The E-Simulator uses ADVENTYRECluster (ADVC)/ADVENTURE as a platform (Akiba et al. 2006, Ohsaki et al. 2009). ADVC is a commercial software package of parallel finite element (FE) analysis that uses the domain decomposition technique for parallel implementation. ADVENTURE is an open source version, which is a prototype of ADVC. ADVC can solve dynamic nonlinear problems with more than 10 million DOFs for a structure discretized by three-dimensional solid elements. The E-Simulator is conceived as a virtual shaking table, and its final form is a software environment to simulate global and local seismic responses of a city, as assemblage of buildings and infrastructures, by fully taking advantage of recent development of computer science and high-performance computing in computational mechanics. Analyses of Steel Building Frames: As a part of this project, the purpose of this study is to show that the global and local elastoplastic behaviors of steel frames under severe seismic motions can be simultaneously simulated by a high-precision FE-analysis software, E-Simulator. Elastoplastic dynamic analyses are carried out for a 31-story high-rise steel building model and for the 4-story frame model that models the specimen of full-scale shaking-table test conducted at E-Defense shaking-table facility. The whole structures are discretized using hexahedral solid elements without resort to macro models such as plastic hinge and composite beam effect. Conclusion: It is shown that E-Simulator can simulate the large-strain elastoplastic dynamic behaviors of the steel building frames. Both global and local behaviors of the structures are estimated accurately by the simulation using fine meshes with the solid elements. References: Hori et al., Journal of Earthquake Engineering 29, 1420-1425, 2007 (in Japanese) Akiba et al., Proc. of SC06, 2006 Ohsaki et al., EESD, 38, 635-654, 200.

Form Finding Analysis Based on Variational Method for Multistable Structure Utilizing Snap-Through Behaviour

Kurokawa, T., Shigematsu, M., and Kohiyama, M.

9th World Congress on Computational Mechanics and 4th Asian Pacific Congress on Computational Mechanics (WCCM/APCOM 2010) (International Association for Computational Mechanics) 10 2010.07

Research paper (international conference proceedings), Joint Work

This study proposed a multistable structure using snap-through behavior as an adaptable structure, which can change its size and transform its configuration easily. To know the stable configuration and stress of the structure, the form finding analysis method of the structure is formulated. Then, a design support system is proposed based on a calculation method of required forces to transform its configuration. Finally, several configurations are demonstrated with a small scale model to show the adaptability and feasibility of the proposed structure.

Frequency Shaping and Variable Gain Feedback to Control Seismic Response of a Building and Elevator Rope

Kohiyama, M. and Baba, T.

5th World Conference on Structural Control and Monitoring (International Association for Structural Control and Monitoring) 8 2010.07

Research paper (international conference proceedings), Joint Work

This paper first clarifies the vibration characteristics of elevator rope in a high-rise building with a response control system such as active mass damper and linked structures. When a cost function for optimal control is formulated to reduce distance between a building and rope, response of the building deteriorates especially in high frequency range. In order to overcome this drawback, a control method is proposed based on frequency shaping linear quadratic Gaussian and variable gain feedback. Time history analysis is carried out using simulated ground motion and it is verified that the proposed method can reduce the response of both a building and rope effectively.

Simultaneous Optimal Design of Structural and Control Systems of a Building under Seismic Excitation Using a Design Response Spectrum

Horiguchi, C. and Kohiyama, M.

6th China-Japan-Korea Joint Symposium on Optimization of Structural and Mechanical Systems (Japan Society of Mechanical Engineers & International Society for Structural and Multidisciplinary Optimization) 5 2010.06

Research paper (international conference proceedings), Joint Work

A simultaneous optimization method is proposed for a structural system controlled by a least quadratic regulator (LQR) under seismic excitation. An LQR-controlled system is converted into an equivalent uncontrolled structural system and the natural period and the damping factor are derived. A design response spectrum is used to consider input earthquake motion and the maximum response and control force of the system are calculated based on the spectrum. Simultaneous optimization consists of the following two stages: 1) feasible region of design variables are evaluated; 2) the objective function of the cost of the total system is minimized. A single mass structure with LQR controller is simultaneously optimized as a numerical example.

Parallel FE-Analysis for Collapse Simulation of 4-Story Steel Building Frame

Miyamura, T., Ohsaki, M., Kohiyama, M., Onda, K., Isobe, D., Akiba, H., Hori, M., Kajiwara, K., and Ine, T.

Joint Conference Proceedings of 7th International Conference on Urban Earthquake Engineering (7CUEE) & 5th International Conference on Earthquake Engineering (5ICEE) (Center for Urban Earthquake Engineering, Tokyo Institute of Technology) 887-892 2010.03

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

The results of high-precision FE-analysis is presented for simulation of collapse behavior of the 4-story steel building frame that is the specimen of the full-scale total collapse shaking-table test conducted in September 2007 at E-Defense. The computation is carried out using the E-Simulator, which is under development at Hyogo Earthquake Engineering Research Center (E-Defense) of National Research Institute of Earth Science and Disaster Prevention (NIED), Japan. The E-Simulator uses the parallel finite element (FE) analysis software package called ADVENTYRECluster (ADVC) as a platform. It is shown through numerical examples that elastoplastic dynamic responses can be estimated with good accuracy using a high-precision FE-analysis without resort to macro models such as plastic hinge and composite beam effect.

Seismic Response Control of a Building and Elevator Rope with Active Mass Damper

Baba, T. and Kohiyama, M.

Theoretical and Applied Mechanics Japan (National Committee for IUTAM, Science Council of Japan) 58 19-30 2010.02

Research paper (scientific journal), Joint Work, Accepted

Elevator rope-sway is a serious problem for a high-rise building under seismic excitation. Vibration control of the rope-sway using active mass damper (AMD) is investigated, which is usually designed simply for control of building response. The linear quadratic regulator (LQR) is employed as the AMD control system. Numerical simulations are conducted and the responses are analyzed in both frequency and time domains. The relative displacement between the building and the rope is evaluated as well as the story drift and the absolute acceleration of the building. It is observed that the control method considering the rope-sway can effectively decrease response of the rope after seismic excitations.

Effect of Spatially Random Ground Motions on a One-Story Wooden Building Considering stiffness of Horizontal Diaphragm

Nanako MIURA and Masayuki KOHIYAMA

Journal of Structural and Construction Engineering (Transactions of AIJ) (Architectural Institute of Japan) 74 ( 645 ) 1975-1982 2009.11

Research paper (scientific journal), Joint Work, Accepted

This paper studies the effect of spatially random ground motions on the seismic response of a one-story multi-span wooden building considering the stiffness of the horizontal diaphragms. The deformation angles at columns and horizontal diaphragms are examined using time history response analyses with simulated input motions. It is shown that stiffness increase of the horizontal diaphragms and dimensions increase of the building make responses large to damage, and that large responses at the horizontal diaphragms are much more serious than at columns.

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A Comparative Study on Equivalent Linear Model to Assess Occurrence of Building Damage

Niikawa, Y. and Kohiyama, M.

10th International Conference on Structural Safety and Reliability (International Association for Structural Safety and Reliability) 3167-3174 2009.09

Research paper (conference, symposium, etc.), Joint Work, Accepted

This study investigates equivalent linear models which can assess occurrence of building damage with high accuracy for several threshold values. The accuracy of the following three equivalent linear models are examined: 1) the conventional model of which stiffness of all the story is determined based on seismic story shear force, 2) the shear-force-equivalent model of which equivalent stiffness of the first story is determined based on seismic story shear force, and 3) the energy-equivalent model of which equivalent stiffness of the first story is determined based on earthquake input energy. The equivalent damping is obtained from input energy of earthquake motion using nonlinear models. As a result, the most accurate equivalent linear model is the shear-force-equivalent model.

Large Scale Parallel Structural Analysis System and Its Application to Nonlinear Seismic Analysis of High Rise Building Frames

Akiba, H., Ohsaki, M., Miyamura, T., Kohiyama, M., Isobe, D., Hori, M., Kajiwara, K., and Ine, T.

Chinese Congress of Theoretical and Applied Mechanics 2009 (The Chinese Society of Theoretical and Applied Mechanics) 280-292 2009.08

Research paper (international conference proceedings), Joint Work

様々な工業製品の設計解析において，大規模構造計算は重要で現実的なツールになりつつある。有限要素解析における解析の並列化の困難は克服されつつあり，近年の高性能計算機を有効活用できるようになってきている。兵庫耐震工学研究センターの数値震動台（E-シミュレーター）は，解析コードADVENTUREClusterをプラットフォームとしており，コースグリッド共役勾配法を用いた並列解析により陰解法による大規模構造解析を可能にした。これを用いた31層超高層建物の地震応答解析の事例を報告した。

Vulnerability Functions for Wooden Buildings Using A Probability Distribution Model of seismic Performance

Masayuki KOHIYAMA and Masashi SHIOMI

Journal of Structural and Construction Engineering (Transactions of AIJ) (Architectural Institute of Japan) 74 ( 640 ) 1029-1036 2009.06

Research paper (scientific journal), Joint Work, Accepted

Vulnerability functions for wooden buildings are proposed, which employ a probability distribution model of seismic performance. An acceleration response spectrum is used as input to the functions. The probability distribution model is formulated based on two indices of seismic diagnosis data: stiffness and resistance force, and it is clarified that the bivariate normal distribution is a reliable model. Regarding estimation accuracy, the proposed functions are compared with experience-based vulnerability functions in past literature for three earthquake disasters. The proposed functions indicate fairly good accuracy when proper parameters of stiffness increase and resistance force increase due to non-structural walls are used.

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High-precision finite element analysis of elastoplastic dynamic responses of super-high-rise steel frames

Ohsaki, M., Miyamura, T., Kohiyama, M., Hori, M., Noguchi, H., Akiba, H., Kajiwara, K., and Ine, T.

Earthquake Engineering and Structural Dynamics (John Wiley & Sons) 38 ( 5 ) 635-654 2009.04

Research paper (scientific journal), Joint Work, Accepted

A new framework is presented for analysis of dynamic collapse behavior of steel frames using large-scale parallel finite element method based on the domain decomposition method. The analysis software is based on ADVC as a part of the E-Simulator that takes advantage of recent development of computer science and high-performance parallel computing in computational mechanics. By making an analysis model with fine meshing, a complicated sequence of local buckling of columns and beams can be simulated. Numerical results are shown for dynamic collapse analysis of single-story and 5-story frame models to show that the global and local behaviors are simultaneously simulated by a high-precision finite element analysis. Eigenvalue analysis is also carried out for a 31-story frame to demonstrate that dynamic analysis can be carried out for a structure discretized to solid elements with more than 70 million DOFs.

Incentives and Disincentives Analysis for Improving Policy for Seismic Risk Management of Homeowners in Japan

Masayuki Kohiyama, Anne S. Kiremidjian, Kimiro Meguro, Miho Yoshimura Ohara

Natural Hazards Review (American Society of Civil Engineers) 9 ( 4 ) 170-178 2008.11

Research paper (scientific journal), Joint Work, Accepted, ISSN 15276988

In order to improve policy and programs to promote retrofitting of houses in Japan, incentives and disincentives for seismic risk management by homeowners were studied by two approaches: a fault tree analysis (FTA) method and a questionnaire survey to homeowners. The result of the FTA revealed two common causes that hindered homeowners’ seismic risk management: disaster awareness problem and fear of dishonest contractors. The questionnaire survey identified both incentives and disincentives. It was observed that neighbors could prompt retrofitting statistically significantly, and there were three major disincentives to retrofitting: high retrofitting cost, low contractor credibility, and little engineering information. The current policy in Japan put emphasis on seismic diagnosis in comparison with those in the United States. However, based on the above-mentioned observations, it was suggested that planning and reviewing of retrofitting work, as well as management after retrofitting, should be assisted more comprehensively in order to promote retrofitting. In addition, more attention should be paid to risk communication to provide engineering information on retrofitting, to foster mutual trust between homeowners and contractors/engineers, and to encourage information exchange with neighbors.

Vulnerability Functions for Wooden Houses Based on Seismic Diagnosis Data and Equivalent Linear Models

Kohiyama, M., Shiomi, M.

14th World Conference on Earthquake Engineering (International Association for Earthquake Engineering) 8 2008.10

Research paper (international conference proceedings), Joint Work

Vulnerability functions of wooden houses, which use the results of seismic diagnosis and an acceleration response spectrum, are formulated using equivalent linear models. They employ a probability density function of seismic performance indices of wooden houses, which are separated into an index of the resistance force and other indices related to the degradation of resistance force. The input seismic motion is evaluated based on an acceleration response spectrum and a natural period is determined by the indices of resistance force and threshold of damage. The application results to the 1995 Hyogo-ken Nanbu earthquake are compared with the damage statistics at the five sites, which have seismic records. The estimated damage ratios coincide fairly well with the actual damage surveyed by local governments.

Development of Extremely Large-Scale Analysis Software (E-Simulator: Virtual Shaking Table) for Earthquake Dynamic Collapse Analysis of Structures

Ine, T., Hori, M., Noguchi, H., Ohsaki, M., Miyamura, T., Oguni, K.， Kohiyama, M., Kajiwara, K., and Akiba, H.

14th World Conference on Earthquake Engineering (International Association for Earthquake Engineering) 8 2008.10

Research paper (international conference proceedings), Joint Work

This report presents a research project of developing “E-Simulator: virtual shaking table”, which is 　a simulation software based on a finite element method to analyze non-linear seismic response of constructions, as a part of E-Defense project. The key features of E-Simulator are 1) extremely large-scale numerical computation that realizes the finest temporal and spatial resolution of the structure response and 2) simulation of collapsing processes of structures that is comparable with the 3D full-scale model earthquake tests of E-Defense. This report explains the objectives of the E-Simulator and its two features. It also introduces the current state of E-Simulator project which includes the earthquake dynamic collapse analysis of 31-story steel framed structure and particle discretization scheme FEM for the RC structure.

Examination of a Simple Ground Model to Estimate Local Seismic Waves in an Irregular Ground Area

Horiike, M., Tagawa, S. and Kohiyama, M.

14th World Conference on Earthquake Engineering (International Association for Earthquake Engineering) 8 2008.10

Research paper (international conference proceedings), Joint Work

Accuracy of estimated seismic waves using a one-dimensional ground model is examined. Hiyoshi Area in Yokohama is focused, which has relatively complicated topography. First, two one-dimensional layered ground models are prepared: Model 1, a four-layered model based on a boring log and Model 2, a two-layered model based on airborne laser profiler and geological cross sections. Seismic records with peak ground acceleration 8 to 141 cm/s2 are used for analysis, which were observed by six seismic stations in the study area. Incident waves at bedrock level of each observation point are calculated by one-dimensional equivalent linear analysis. Two ground models are compared with respect to acceleration response spectra. Then, acceleration response spectra at bedrock level at each observation point are compared in regard to each earthquake event. The results suggest that it is necessary to increase the spatial density of bedrock data to make an accurate ground model and to consider influence of surface waves and oblique incidence in regard to the studied area.

Damage Detection of a Reinforced Concrete Beam Based on Fourier Spectrum of Response to Impact Excitation

Sano, A., Kumagai, Y. and Kohiyama, M.

Theoretical and Applied Mechanics Japan (National Committee for IUTAM, Science Council of Japan) 56 77-85 2008.01

Research paper (scientific journal), Joint Work, Accepted

In order to develop damage detection method for a reinforced concrete (RC) structure using an impact hammer excitation, some indices based on Fourier spectrum of a response accelerogram were analyzed. Two test pieces of a RC beam were used: one has sufficient shear reinforcement and the other not. To cause nine stages of damage, a test piece was simply supported and vertical downward forces were loaded. At each damage stage, an impulse excitation was applied and the response acceleration was measured. It was revealed that an index using phase difference spectrum showed fairly good correlation with damage by which bending stiffness was reduced although the index used no information on excitation force. Between the two test pieces, clear difference of the correlation was not observed possibly because bending cracks proceeded for both test pieces.

Isolator Level in Height of Seismic Isolation System with Semi-Active Control

Yamamura, T. and Kohiyama, M.

Theoretical and Applied Mechanics Japan (National Committee for IUTAM, Science Council of Japan) 56 153-163 2008.01

Research paper (scientific journal), Joint Work, Accepted

Recently, buildings with an isolation device installed in middle story have been constructed. However, an adequate isolation layer level in height of a mid-story isolated building has not been established, and this causes a restriction on design of a plan of a mid-story isolated building. To reduce this restriction, semi-active controlled systems are compared to observe response characteristics. Regarding a control law, velocity feedback based on bilinear optimal control is used. Based on time history analysis with a 30-DOF system, response differences with respect to a position of an isolation layer is studied. It is observed that semi-active control scheme can be used to reduce the absolute acceleration of a roof and the deformation of an isolation layer. On the other hand, much attention must be paid to behavior of a lower structure under seismic excitation in design.

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