Nikken Sekkei Ltd.

Engineering, Japan

Nikken Sekkei Ltd.

Engineering, Japan
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Imaeda H.,NIKKEN SEKKEI LTD | Harada H.,NIKKEN SEKKEI LTD | Shinohara T.,NIKKEN SEKKEI LTD
Procedia Engineering | Year: 2017

The writers have developed a damage estimation system to evaluate the level of vibration and the damage state of a building after an earthquake. This system is already in operation in several buildings. It consists in setting three-axis-acceleration sensors in a limited number of floor of a building and to estimate the acceleration of the other floors based on spline interpolation. Then, acceleration is integrated to calculate the velocity, the relative displacement and the absolute displacement; which are compared with threshold values designed by a structural engineer to give a quantitative estimation of damage intensity. Five items are considered: the main structure, the cladding, the MEP, the ceiling and the furniture. This system is in operation in Nikken Sekkei Tokyo building since 2014 and recorded, among other, the March 2015 Ogasawara open sea earthquake. This report proposes a comparison of the results of this system and of numerical calculations for several recorded earthquake to validate the performances of this damage estimation system. © 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.


Yoshida Y.,Osaka University | Shimoda Y.,Osaka University | Ohashi T.,Nikken Sekkei Ltd.
Energy and Buildings | Year: 2017

This paper reports strategies toward achieving a sustainable campus at Osaka University, Japan. We advance a daily energy-use schedule for each building type to provide effective energy-saving strategies. We classify the facilities into three categories according to department type to reveal their energy-use patterns and identify their strategies for saving energy. These strategies will contribute to a sustainable campus using photovoltaic generation. Not only the implementation of energy-saving technologies but also the installation of renewable energy technologies will realize a sustainable campus at Osaka University. Category I (liberal arts) buildings have low energy density. The energy efficiency strategy for Category I is to develop zero-energy buildings by tuning the energy system to people's daily routines. Category II (science and engineering) buildings have high energy density. The energy efficiency strategy for Category II is effective energy conservation using the plan–do–check–act cycle. Category III buildings are large-scale facilities with experimental laboratories. The energy efficiency strategy for Category III is outsourcing energy management to an energy service company. Compared with fiscal year 2010, in 2015 Osaka University decreased energy use per unit floor space by 22%. It achieved these savings despite an increase in total floor area during that period. © 2017 Elsevier B.V.


Takebayashi H.,Kobe University | Kasahara M.,Nikken Sekkei Ltd. | Tanabe S.,Nikken Sekkei Ltd. | Kouyama M.,Nikken Sekkei Ltd.
Sustainability (Switzerland) | Year: 2017

Work and leisure in outdoor spaces influences people's physiological and psychological, while it can also lead to a reduction of energy consumed via air conditioning and lighting. In this study, the effects of solar radiation shading by trees in the open space around buildings on microclimatic development and pedestrian radiation environment are evaluated through a case study on the redevelopment buildings in front of Central Osaka Station, based on both observation and calculation. In both open space and green garden, direct solar radiation is shielded mainly by the buildings located behind the trees rather than by the trees themselves. Solar radiation shielding by trees is necessary in the range of more than 10 m from the south side of the buildings and more than 6 m from the west or east sides of the buildings. © 2017 by the authors.


Yamaguchi T.,Nikken Sekkei Ltd. | Katsura T.,Hokkaido University | Nakamura Y.,Nippon Steel and Sumikin Engineering
Journal of Environmental Engineering (Japan) | Year: 2015

The authors established a technique for measuring calorie output from a variable refrigerant flow air conditioning system by applying the refrigerant enthalpy method. In this paper, the advantages of the measuring technique and its detailed estimation process of the calorie output are introduced. In addition, the measurement with water cooled variable refrigerant flow air conditioning system was carried out in order to confirm the accuracy of technique. In this actual measurement, it was shown that measuring the appropriate pressure of refrigerant in the heat pump is important to achieve the measurement accuracy. As the another results of actual measurement, the error of estimation values of heat quantity between the established technique and the conventional one is less than 20 % for cooling and heating, respectively. Therefore, the technique for measuring calorie output that the authors established has the high measurement accuracy. In addition, the authors suggested operation improvement method by analyzing measured values such as pressure, calorie output, electric power consumption and so on. As the results, it was confirmed that COPs is improved in the cooling period by lowering the high side pressure of refrigerant in the heat pump depending on the inlet water temperature in the primary side of the pump.


Yasunaga J.,Jfe Holdings | Yamaguchi T.,Nikken Sekkei Ltd. | Uematsu Y.,Tohoku University
Journal of Wind Engineering | Year: 2016

The present paper investigates the buckling and vibration behavior of open-topped oil-storage tanks under wind loads based on a finite element analysis. Focus is on the effects of wind girders on such behavior. The wind force coefficients obtained in a turbulent boundary layer is used in the analysis. From the results of buckling analysis, the effects of top/intermediate wind girders on the buckling load and mode of tank shells are made clear. Furthermore, the effect of wind force distribution on the buckling load is discussed based on the results obtained from wind tunnel experiments with two or three tank models in in-line arrangement. A time-history analysis is also carried out in order to investigate the effect of the rigidity of wind girders on the vibration of tank shells. The stresses involved in the tank walls are found to be fairly small, provided that the wind girders are relatively rigid. Finally, the design recommendations of wind girders installed on an open-topped oil storage tanks are proposed, which provide more reasonable design criteria for the wind girders than the current guidelines.


Kuwayama K.,University of Kitakyushu | Shiraishi Y.,University of Kitakyushu | Iida R.,Nikken Sekkei Ltd.
Ventilation 2015 - Proceedings of the 11th International Conference on Industrial Ventilation | Year: 2015

It is necessary to simulate both the air-conditioning unit and the indoor environment. Sensing the thermal environment in working spaces is problematic for controlling HVAC systems. Because workers usually remain near their desk, the thermal environment should be measured around desks. However, air temperature is measured on the wall or inlet of air-conditioning units. In addition, indoor thermal environments should be evaluated by using voting systems to include the effects of factors such as air temperature and mean radiant temperature, and relate this to the performance of cooling and heating systems; however, there are few studies of this type of evaluation. In this study, we conducted case studies of the coupled simulation of the integrated energy simulation tool BEST and CFD analysis by a two-node thermoregulation model (2NM) as air-conditioning sensors for office space. The validity of the coupled simulation model was demonstrated by comparison with the indoor thermal environment and air-conditioning heat load measured by air temperature sensors on the wall surface. The indoor thermal environment and air-conditioning heat load depended on the location and method of sensing. The validity of air-conditioning control by installing 2NM in a task region was demonstrated. In future work, we will create a coupled simulation model reproducing office space in detail.


Shinomiya N.,Kobe University | Takada S.,Kobe University | Ushio T.,Nikken Sekkei Ltd.
Energy Procedia | Year: 2015

In winter, the stack effect causes problems in high-rise buildings. In order to prevent it, it is necessary to clarify significant factors influencing ventilation behaviors for whole building. In this paper, the pressure differences at elevator doors were measured through one winter for an actual high-rise building in use. Furthermore the correlation of pressure differences with the parameters such as time, the temperature differences between elevator shafts and outdoor air and the outdoor wind velocity was studied. It was suggested that opening of entrance and elevator doors might influence significantly pressure differences, and thus the ventilation behavior of whole building. © 2015 The Authors.


Kashima Y.,University of Kitakyushu | Shiraishi Y.,University of Kitakyushu | Iida R.,Nikken Sekkei Ltd. | Tsukami S.,Nikken Sekkei Ltd.
Ventilation 2015 - Proceedings of the 11th International Conference on Industrial Ventilation | Year: 2015

In this study, we verify the performance of indoor environment by evaluating the thermal and air environment in detail in the hospital mall with floor radiant and under floor air-conditioning (A/C) system, based on CFD analysis. Therefore, we clarify the characteristic of this system by comparison with wall supply AC system (package A/C system). The following results were obtained: (1) According to the results of CFD analysis for this space, uniform indoor thermal environment was confirmed by using both floor radiant and under floor cooling system. (2) Combined application of floor radiant and under floor cooling system in large space was suggested that was useful about thermal environment and energy saving in comparison with wall supply A/C system.


Yamane T.,Nikken Sekkei Ltd. | Nagahashi S.,Chiba Institute of Technology
Journal of Structural and Construction Engineering | Year: 2010

The purpose of this paper is to present a superposition technique for seismic waves from consecutive earthquakes. Seismic waves from each earthquake are synthesized by the waveform generation methods proposed in previous papers. The consecutive seismic waveforms are superposed so as to match the positions on the time history axis with respect to a wave arriving from the border between fault planes, considering the relationship between the distribution of phase differences and the time history of the accelerogram. By analyzing the dynamic behavior of high-rise buildings using the proposed superposition technique, it is indicated that a proper evaluation of ground motions is important in the case of consecutive earthquakes.


Kobori T.,Nikken Sekkei Ltd. | Konishi A.,Nikken Sekkei Ltd.
Proceedings of the 13th East Asia-Pacific Conference on Structural Engineering and Construction, EASEC 2013 | Year: 2013

This paper describes the structural design of TOKYO SKYTREE® which was completed in May last year. This tower is the world's highest freestanding steel tower, and it was planned to be the central facility for digital broadcasts in the Tokyo area. Structures in Japan are required to be sufficiently safe against the severe natural environment of Japan, which include not only earthquakes but also typhoons. This tower is also to serve the important role of distributing information during disasters, so even more severe criteria were provided for its design. The following is an introduction to the structural design of TOKYO SKYTREE, which satisfies the strict design conditions using a unique The Core Column System, vibration control system.

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