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Ko B.,University of Tokyo | Koga T.,University of Tokyo | Lu B.,NIKKEN SEKKEI | Hirate K.,University of Tokyo | And 2 more authors.
Journal of the Illuminating Engineering Institute of Japan (Shomei Gakkai Shi) | Year: 2013

We assume that when people look around an entire space, the total impression is created through the accumulation of visual information in every direction. We define "brightness of a space" and examine the impact factors and quantification. The results of previous studies suggest that it is reasonable to use average luminance and luminance contrast. However, when the entire space is defined as "brightness of a space", luminance contrast cannot be applied. For this reason, we consider the physical quantity that shows the variation of the brightness in our evaluation experiment on Brightness. It is possible to propose using a prediction equation of " brightness of a space" using the standard deviation of the logarithm of the luminance values and average luminance. Source


Matsushita T.,Nagoya University | Nishizawa T.,NIKKEN SEKKEI | Tobita J.,Nagoya University | Fukuwa N.,Nagoya University
AIJ Journal of Technology and Design | Year: 2014

Vibration characteristics of a high-rise building has examined by microtremor observation, free vibration test and earthquake observation. Natural frequencies and damping ratios for lower modes are estimated by microtremor tests, free vibration tests with AMD and man-powered excitations. Natural frequencies are shown to be lowered approximately 2% comparing to the situation soon after the construction. Relatively low damping ratios less than 1% are stably obtained. Amplitude dependent characteristics are slightly observed in estimated natural frequencies. Vibration characteristics during low-level earthquake response are estimated. Obtained properties during several years are effective for structural health evaluation after the large earthquake response. Source


Moriki A.,Kyushu Regional Construction Bureau | Terashi M.,NIKKEN SEKKEI
14th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering | Year: 2011

The mechanical dewatering technique has been developed to decrease the volume of clay slurry. In the case where it is possible to utilize dewatered clay lumps as geomaterials for embankment, two effects on extension of the life of disposal pond can be achieved simultaneously. In this paper, the mechanical properties of individual dewatered clay lump and aggregates are described based on the results of laboratory tests and a large scale trial construction. The dewatered clay lumps are confirmed to be a good geomaterial. Source


Nishizawa T.,NIKKEN SEKKEI | Ohno T.,NIKKEN SEKKEI | Tobita J.,Nagoya University | Fukuwa N.,Nagoya University
Journal of Structural and Construction Engineering | Year: 2010

We have been measuring the performance of plural buildings by mounting optical fiber sensors capable of measuring static and dynamic displacement on some columns of plural buildings in the process of being constructed, in order to grasp and verify their performance from the difference between the performance of actual buildings and their design performance. We analyzed the results of the measurement and reached the conclusion that measurement using optical fiber sensors is applicable to (1) evaluations of the performance of buildings, structural systems, and construction quality based on the analysis of the difference between the performance of actual buildings and their design performance, (2) feedback to future design, and (3) the estimation of the degree of damage to buildings after a disaster. In this paper, we describe particularly dynamic measurement results of the measurement we have conducted on two skyscrapers whose elevational shape is irregular, or regular, and describe the utility of the measurement system to suggest, and show future prospects. Source


Nishizawa T.,NIKKEN SEKKEI | Ohno T.,NIKKEN SEKKEI | Tobita J.,Nagoya University | Fukuwa N.,Nagoya University
AIJ Journal of Technology and Design | Year: 2012

We measure an axial strain of CFT columns of real buildings by optical fiber sensor, and compare an analysis result with a measurement result and analyze it. It was comparatively good about the dynamic axial strain of small amplitude, but it was difficult as a result of past examination. Evaluation of the influence such as the shrinkage behavior of the filling concrete of CFT columns was always hindrances of the conversion to column axial force from column axial strain by the dead load. We performed an experiment to grasp shrinkage behavior of the filling concrete of CFT columns from such a background. Furthermore, We performed loading test and considered influence of the shrinkage of the filling concrete. Source

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