Center for Better Living

Utsunomiya-shi, Japan

Center for Better Living

Utsunomiya-shi, Japan
SEARCH FILTERS
Time filter
Source Type

Kinjo H.,Center for Better Living | Horio T.,Center for Better Living | Hirashima T.,Chiba University | Katakura Y.,Chiba University | And 2 more authors.
Journal of Structural and Construction Engineering | Year: 2016

Timber elements, which are different from other structural elements, have a characteristic problem in that the load bearing capacity decreases due to self-burning in the case of a fire, and this self-burning may continue after other fuel in the room has been exhausted. Therefore, the structural fire performance of timber elements should be clarified during not only the heating phase, but also the cooling phase. In the present paper, deflection behaviour and failure mode of larch glued laminated timber beams exposed to fire heating and natural cooling is discussed based on load-bearing fire tests in which load level is the test parameter.


Ohno Y.,Center for Better Living | Masuda Y.,Utsunomiya University | Kage T.,Japan Building Research Institute
Journal of Structural and Construction Engineering | Year: 2012

The drying shrinkage is the main cause of cracks in reinforced concrete. Therefore, it is important to the effect of drying shrinkage of material. In this study, it was shown the effect of drying shrinkage of cement and shrinkage reducing agent, considering mix proportion and drying ratio. In this experiment, several cements and shrinkage reducing agents were used. The results of experiments for drying shrinkage, a large effects of cements and shrinkage reducing agents, whereas a small effect of expansiveadditive. Moreover, the effects of drying shrinkage of materials were evaluated.


Iwase T.,Niigata University | Horiguchi Y.,Niigata University | Yasuoka H.,Center for Better Living
20th International Congress on Acoustics 2010, ICA 2010 - Incorporating Proceedings of the 2010 Annual Conference of the Australian Acoustical Society | Year: 2010

Concrete is useful and indispensable material for the construction of modern buildings. However, it contracts after drying and causes cracks on its surface and in structure body. Moreover, long use period after construction make the crack deeper and wider. These bad states will cause peeling off and falling accidents. To prevent the accident, diagnose of the crack is necessary. Famous detection method for crack depth using ultrasonic wave was not used for inspection of concrete wall with wide area because there were faults with high cost and severe test condition as using grease. Therefore, authors tested other detection techniques for the crack depth, and then we found that the air column resonance being caused by a crack is similar to a wind instrument. It can be understood that the length of 1/4 of the wavelength of the first order resonance sound wave corresponds almost to the depth of air column with one end closed and the length of 1/2 of wavelength also to the depth with both ends open. We propose the method of nondestructive detecting crack depth based on the resonance phenomena. It has been understood that it would be able to detect for the width within 1mm on concrete wall in typical building by the spectral analysis peak at frequency of several hundred hertz. Under assumption of expanded use for special concrete constructions with very thick wall, we made some detection experiments by the addition. If depth increased, and width narrows, it became difficult to detect by the first order resonance as at frequency lower than one hundred hertz. Fortunately, higher order resonance phenomena, as at frequency several hundred hertz, were found and were able to be clearly caught in the experiments. It is possible to detect even by deep depth of about 1m with width of about 1 and 2mm. In the paper, principle and measurement ways of diagnosis based on the sound resonance are introduced, and the examination results are described. Copyright© (2010) by the International Congress on Acoustics.


Yasukawa M.,Waseda University | Yasui N.,Waseda University | Suzuki A.,Obayashi Corporation | Hasemi Y.,Waseda University | And 6 more authors.
AIJ Journal of Technology and Design | Year: 2013

Fire resistance tests were conducted on loaded beam and post-beam joints of heavy hardwood (ZELKOVA) designed for traditional temple buildings. The tests revealed the followings: (1) predictability of the structural fire resistance of ZELKOVA beam with safety margin by the assessment of the bending buckling. (2) applicability of the traditional beam and post-beam joint designs to the Quasi-fireproof construction.


Nakagawa T.,Japan Building Research Institute | Kawai N.,Japan Building Research Institute | Okabe M.,Center for Better Living
AIJ Journal of Technology and Design | Year: 2011

In this study, bending tests of continuous footing foundation reinforced by the several kind of seismic retrofit constructions were carried out. The retrofit constructions used in this study were made by additional concrete casting and carbon fiber sheet reinforcing. The tests were carried out by the three-point bending that has 3.6m length spans. The specimens whose beam and footing retrofitted by the additional casting had equivalent seismic resistance as the reinforced concrete foundations. But the other specimens didn't have enough seismic resistance.


Mizukami T.,Center for Better Living | Tanaka T.,Kyoto University
Procedia Engineering | Year: 2013

Simple equations for predicting thermal resistance of mud-plastered wall containing moisture are proposed. These are based upon the semi-infinite body heat conduction theory and a moving moisture boundary model. Standard fire resistance tests are conducted for mud-plastered wall and one dimensional finite difference model for thermal conduction with the effect of latent heat of moisture evaporation is executed to validate the equations. The results show that the equations are able to predict the temperature rise of moisture containing wall with reasonable accuracy and identify the contribution ratio of moisture and thermal diffusivity to the temperature rise. The equations are also able to be used to estimate the apparent value of thermal diffusivity from the test results. © 2013 International Association for Fire Safety Science.


Kawabata Y.,Shinshu University | Nakagomi T.,Shinshu University | Sakino Y.,Osaka University | Hattori K.,Center for Better Living | Tobori K.,Tomi City Office
Journal of Structural and Construction Engineering | Year: 2011

The weld defect of the welded beam-to-column joint in steel structure causes the brittle fracture and has possibilities to reduce the deformation capacity. It is considered that the effect of the weld defect on the deformation capacity from the difference of between shop and site welding beam-to-column joints is different. Therefore it is important to understand this difference. In this paper, full-scale welding test was done it were shop and site welding beam-to-column joints. Then, the effect of the deformation capacity of test specimens caused by the difference of the position of welding defects between two joint methods was studied. As the results, the deterioration ot deformation capacity caused by the welding delect was low using shop welding beam-to-column joints. and high using site welding beam-to-column joints.


Ohashi H.,Takenaka Corporation | Nagomori H.,Takenaka Corporation | Yamamoto M.,Center for Better Living | Yusa S.,Tokyo University of Science | And 6 more authors.
AIJ Journal of Technology and Design | Year: 2015

Fire-resisting wood structural elements for building were developed. It is composed of three layers made of glued laminated timber, "a load-bearing part, a self-charring-stop and a surface layer". Tree species of load-bearing part is limited to the only kind. In order to enable a species different, this research was carried out. Fire resistance test was performed to demonstrate the effect on fire resistance of the wood density. The relationship of fire resistance and wood density of the load-bearing part was clear. Usage of high wood density of the load-bearing part was obtained a conclusion that is advantageous to fire performance.


Kinjo H.,Tsukuba Building Research and Testing Laboratory Center for Better Living | Yusa S.,Center for Better Living | Horio T.,Tsukuba Building Research and Testing Laboratory Center for Better Living | Hirashima T.,Chiba University | And 2 more authors.
Journal of Structural and Construction Engineering | Year: 2015

Timber elements, which are different from other structural elements, have a characteristic problem in that the load bearing capacity decreases due to self-burning in the case of a fire, and this self-burning may continue after other fuel in the room has been exhausted. Therefore, the structural fire performance of timber elements should be clarified during not only the heating phase, but also the cooling phase. However, in examining the load bearing capacity of timber elements in a fire, few studies have considered the cooling phase. In the present paper, the fire performance of glued, laminated timber beams is discussed based on load-bearing fire tests that take the cooling phase into consideration. © 2015, Architectural Institute of Japan. All rights reserved.


Okabe M.,Center for Better Living | Okabe M.,Gifu University | Yasumura M.,University of Shizuoka | Kobayashi K.,University of Shizuoka | And 2 more authors.
World Conference on Timber Engineering 2012, WCTE 2012 | Year: 2012

Structural performance of shear walls to resist against wind and seismic loading is evaluated by applying static or cyclic load testing. IS021581 specifies the static and cyclic lateral load test for shear wall. ISO defines two method of lateral load test. Method 1 shows the boundary conditions are designed to produce mainly the shear response of the wall. Method 2 shows the boundary conditions are designed to produce mainly the rocking (rigid body rotation of the wall) or combined shear-rocking response of the wall reflecting the intended actual construction details of joints connecting the wall to bottom and top boundaries. Cross Laminated Timber panels (also known as CLT or X-LAM) are relatively new building material and high rigidity and strength compared to sheathing materials. It is possible to apply to low-rise residential buildings from the multi-story timber buildings. In Japan manufacturer has been already trying to produce Sugi CLT. Sugi (Cryptomeria japonica) is most popular softwood in Japan. In this report shows effect of vertical load based on IS021581 method 2 under cyclic lateral load test of Sugi CLT. Vertical load applied three condition, 15kN/m, 30kN/m and without vertical load. Stiffness of CLT wall panel against horizontal load shows higher on vertical load. However maximum strength increase due to vertical load was smaller than the stiffness.

Loading Center for Better Living collaborators
Loading Center for Better Living collaborators