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Hata T.,Toyama Prefectural University | Kaneda K.,Takenaka Research and Development Institute | Tanikawa T.,Takenaka Research and Development Institute
International Journal of GEOMATE | Year: 2016

In recent years, erosion control has been increasingly implemented for land embankments of public roadways (e.g., express highways). In the field of geo-environmental engineering, it is important to develop an easy-to-use maintenance method for such embankments based on a natural process. This study aims to develop an eco-friendly and inexpensive maintenance method for embankment management. In this paper, the general concept of the newly proposed method is presented based on the results of laboratory tests and numerical simulations. The most important advantage of this method is the enhancement of urease activity in the in-situ microorganism community. Laboratory tests showed that microbial carbonate precipitation (MCP)-treated sand can increase the liquefaction strength. The numerical simulation results show that an MCP-treated embankment surface shows a rigid frame structure. These results show that the proposed method is suitable for use as an embankment maintenance method.


Okano T.,Takenaka Research and Development Institute
Applied Acoustics | Year: 2016

Of the two types of rating indices for the heavy weight floor impact sound insulation, the method of utilizing a rubber ball impact source combined with A-weighted sound level and the method utilizing a tire impact source combined with L-rating curve, the advantage of the former has been reported. In order to extend the advantage, the possibility was studied of estimating the rating utilizing the rubber ball impact source, based on the measurement results utilizing the tire impact source, especially for the case of a double leaf wooden floor. The correlation between the indices is not high enough to estimate one of them directly from the other with an accuracy not incorrectly estimating the rating grade of 5 dB step. The use of predictor variables, such as the special specifications of the double leaf wooden floor, for example, the use of sound insulation sheet, and the floor impact sound levels in the 31.5-Hz, 63-Hz and 125-Hz bands, is possibly able to increase the accuracy. Three principal types of multiple regression equation were derived through the analysis of measurement results in existing residential buildings. © 2015 Elsevier Ltd. All rights reserved.


Inoue R.,Takenaka Research and Development Institute | Okano T.,Takenaka Research and Development Institute
AIJ Journal of Technology and Design | Year: 2013

This paper describes the development of passive reduction of heavyweight floor impact sounds by tuned mass dampers set at ceiling. Experiment was carried out with ceiling of the specification of general multiple dwelling houses. By using the tuned mass dampers composed of a viscoelastic body and a 50mm steel cube, the vibration acceleration level of the ceiling was decreased by 12dB. As a result, heavy-weight floor impact sounds level was decreased by 4-5dB.


Kaneda K.,Takenaka Research and Development Institute | Aoki M.,Takenaka Research and Development Institute | Ohtsuka S.,Nagaoka University of Technology
Journal of Structural and Construction Engineering | Year: 2016

In designing superstructures of buildings, it is important to estimate the ultimate bearing capacity of their foundations. The ultimate bearing capacity formula for foundations, which is specified in the guidelines published by the Architectural Institute of Japan for design of building foundation, is widely used by engineers. Recently the evaluation of bearing capacity of foundations under large earthquakes has keenly been focused on. As the foundation width increases, its ultimate bearing capacity gets smaller than the capacity obtained by AIJ's guideline for sandy grounds that is caused by the decline of their internal friction angle or the progressive failure. Besides, the ultimate bearing capacity of large foundations against inclined loads has not been yet made clear. In this paper, by using rigid plastic finite element method, the ultimate bearing capacity of large foundations against inclined load is discussed. The obtained results of the FEM analysis are as follows, 1) The "size effect" can be explained analytically in the large spread foundation by referring to some experimental, in which the internal friction angle declines when the mean effective stress becomes high. 2) For the friction angles 30 and 40 degrees, the size effect should be considered. However, in the case of the inertial friction angle of 40 degrees, the size effect is slightly smaller when compared to the case of 30 degrees.


Ihara T.,Norwegian University of Science and Technology | Ihara T.,Takenaka Research and Development Institute | Gao T.,Norwegian University of Science and Technology | Grynning S.,Norwegian University of Science and Technology | And 4 more authors.
Applied Energy | Year: 2015

Aerogel granulate glazing systems for energy efficient buildings have various promising properties, including their thermal insulation properties and translucent features. In this study, the energy performance of aerogel granulate glazing systems was evaluated by considering an office facade consisting of a translucent aerogel granulate glazing system at spandrels. The results indicate that such a glazing facade can achieve a lower energy demand than a double glazing facade in cooling dominated climates, such as Tokyo and Singapore. It is also possible to secure better energy savings owing to increased daylight passing through translucent spandrels. In heating dominated climates, such as Oslo, the aerogel granulate glazing facade does not attain the same performance as the glazing facade currently most popular, triple glazing facades. However, a combination of aerogel and triple glazing systems may offer an energy efficient facade for cold climates. From an energy saving perspective, aerogel granulate glazing systems have the potential to become a solution in not only cold climates, but also hot and warm climates. These new findings may contribute to new architecture techniques. © 2014 Elsevier Ltd.


Yamada Y.,Takenaka Research and Development Institute
Proceedings of Forum Acusticum | Year: 2011

The potential capability of the active technique to suppress acoustic modes is verified by assuming the ideal condition under which a control model can be made determinate. A control experiment was conducted in a small rectangular room with the realistic scale as an architectural space. Results suggest that the sound field obtained using the Wiener filter would approach a globally controlled state if the number of control points is considerably increased. Also, it was actually confirmed that the global control only reduce the reverberant sound component and does not make any contribution to the direct sound.


Ihara T.,Norwegian University of Science and Technology | Ihara T.,Takenaka Research and Development Institute | Gustavsen A.,Norwegian University of Science and Technology | Jelle B.P.,Norwegian University of Science and Technology | Jelle B.P.,Sintef
Applied Energy | Year: 2015

Properties of facade materials should be considered to determine which of them strongly affect building energy performance, regardless of the building shapes, scales, ideal locations, and building types, and thus may be able to promote energy efficiency in buildings. In this study, the effects of four fundamental facade properties related to the energy efficiency of office buildings in Tokyo, Japan, were investigated with the purpose of reducing the heating and cooling energy demands. Some fundamental design factors such as volume and shape were also considered. It was found that the reduction in both the solar heat gain coefficient and window U-value and increase in the solar reflectance of the opaque parts are promising measures for reducing the energy demand. Conversely, the reduction in the U-value of the opaque parts decreased the heating energy demand, and this was accompanied by an increase in the cooling energy demand in some cases because the total energy demands were predominantly for cooling. The above-mentioned promising measures for reducing building energy demands are thus recommended for use, and an appropriate U-value should be applied to the opaque parts based on careful considerations. This study provides some fundamental ideas to adjust the facade properties of buildings. © 2015 Elsevier Ltd.


Matsushita H.,TAKENAKA Research and Development Institute | Yoshioka H.,TAKENAKA Research and Development Institute | Takahashi Y.,TAKENAKA Research and Development Institute
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

Sheeted or fibrous piezoelectric devices have been recently developed as actuators or sensors. These light and flexible devices are expected to create many innovative methods for the vibration control of structures. In this paper, we discuss the active control of vertical and horizontal micro-vibration of an architectural frame structure using Macro Fiber Composites (MFCs). MFCs are sheeted piezoelectric devices constructed with fibrous piezoceramics that can produce relatively higher forces than other sheeted piezoelectric devices. We arranged MFCs at the lower flange of both ends of a beam as actuators. By the expansion and contraction of the MFC actuators, bending moments act at both ends of the beam. The synchronized movements of the MFC actuators control the vertical vibration of the beam or slab. The opposite phase movements control the horizontal vibration of the frame structure. MFCs used as sensors are arranged at arbitrary positions on the lower flange surface. An experiment of vertical and horizontal vibration control on a scaled frame model is conducted and the results show that the control method effectively minimizes the resonant vibration. A vertical vibration control test on a real architectural structure is also conducted. The MFCs are arranged at the ends of two beam-spanning girders. Consequently, the vertical floor vibration of 0.04 m/s2 at 8.5 Hz at the center of the grid was reduced to 0.01 m/s2 or about -12 dB. © 2014 SPIE.


Okano T.,Takenaka Research and Development Institute | Koyanagi S.,Takenaka Research and Development Institute
Applied Acoustics | Year: 2014

A number of datasets regarding the heavy weighted floor impact sound level and the driving point impedance level, i.e., twenty times the common logarithm of driving point impedance at an exciting point, were measured in existing residential buildings before the floor finishing of the excitation room and the ceiling finishing of the receiving room were installed. These data were compared to the calculated values by the impedance method, i.e., a practical method that estimates vibration energy of an excited slab using the driving point impedance at the exciting point as a major factor, as well as those using the Finite Element Method (FEM) models of slabs. Furthermore, correlations between the residual errors and the major dimensions of the receiving rooms were investigated. Two major error factors were found to influence the calculated values by the impedance method. The spectral characteristic of the tire impact source within the 63 Hz band effectively decreased the prediction errors when it was included in the calculation and combined with the FEM models of slabs. The length of the shorter side of the receiving room plan correlated to the residual errors of the receiving rooms having a pair of flat parallel walls. These errors arise from the fact that the receiving points were placed at the central and quarter positions within the wall distance, where the nodes of the horizontal mode exist. It was not possible to identify another dimension of the receiving room that significantly correlates to the residual errors of the prediction. © 2013 Elsevier Ltd. All rights reserved.


Okano T.,Takenaka Research and Development Institute | Koyanagi S.,Takenaka Research and Development Institute
Applied Acoustics | Year: 2015

In studies of floor impact noise, increasing attention has been paid to the lower frequency range below 100 Hz. Recently, several studies have suggested the importance of including the 31.5 Hz octave band in their evaluations. In this band, the floor impact sound is audible but has not been studied sufficiently. The accuracy of two types of so-called 'impedance' methods is investigated for the purpose of predicting heavy-weight floor impact sound levels in the 31.5 Hz octave band. Although impedance methods are widely used, they are not usually applied to the 31.5 Hz octave band. One of the two models is the usual method, in which the sound field of the receiving room is assumed to be diffuse; and the other is a possible variation in which no acoustical mode is assumed in the receiving room. Floor impact sound levels were estimated from driving point impedance levels measured in existing multiple-dwelling buildings and were compared with the measured floor impact sound levels. The results indicate that a hybrid of the two models, with their use depending on the length of the longer side of the receiving room, has the advantage of minimizing the maximum error. However, the hybrid method is unable to improve the general correspondence between measured and calculated values. A simple statistical correction corresponding to the clamping condition of the slab edges is determined to improve the correspondence. A more precise evaluation of the vibration transmission characteristics within a slab would be necessary for further minimization. © 2015 Elsevier Ltd.

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