Mikio Koshihara

On-Site Lateral Loading Test of a Traditional Timber House in Japan

This paper presents the results of a static lateral loading test performed on a traditional timber farmhouse in Japan. The aim of this research is to clarify the horizontal load carrying capacity and the failure mode of this type of house by full-scale experiment. The house is situated in Yamaguchi prefecture, which is in the southwestern part of Japan, and was built in the late 18th century. The experiment was performed by placing static loading equipment within the house, and placing two reaction supporting systems outside the house. A lateral cyclic loading test was carried out and the maximum lateral load and the failure mode were determined. Static analysis using a theoretical mud wall model was also performed. The results of this analysis are discussed in comparison with those of the experiment.

INFLUENCE OF FIRE EXPOSURE ON THE MECHANICAL PROPERTIES OF WOOD

本論文の実験の骨子及び結果の一部(ケヤキ)については,文献18)で口頭発表した。 *1 早稲田大学大学院 Graduate School, Waseda Univ. *2 早稲田大学理工学術院 教授・工博 Prof., Department of Architecture, Waseda Univ., Ph. D. *3 早稲田大学理工学研究所 招聘研究員・博士(工学) Visiting Researcher, RISE, Waseda Univ., Ph. D. *4 東京都庁 工修 Tokyo Metropolitan Government, M. Eng. (当時 早稲田大学大学院) (Former Waseda Univ.) *5 独立行政法人森林総合研究所 博士(工学) Forestry and Forest Products Research Institute, Ph. D. *6 亀山建設(株) 代表取締役社長・工修 President, Kameyama Construction, M. Eng. *7 椙山女学園大学 教授・工博 Prof., Sugiyama Jogakuen Univ., Ph. D. *8 東京大学生産技術研究所 教授・博士(工学) Prof., Institute of Industrial Science, The University of Tokyo, Ph. D. *9 独立行政法人森林総合研究所 Forestry and Forest Products Research Institute

Timber–Reinforced Concrete Core Hybrid System: Shake Table Experimental Test

AbstractThe law to promote the use of wood in the construction industry was announced by the Japanese government in 2010. As a result of this initiative, timber and timber-based hybrid buildings are increasingly used in public buildings. As the buildings are located in high seismic zone areas, however, validation of the current design guideline was of paramount importance. This paper reports the design and a shake table test of timber frame–reinforced concrete (RC) core hybrid systems. Three specimens (S1, S2, and S3) are tested: S1 and S2 are both one-story buildings with a nailed plywood floor (flexible diaphragm) and a rigid RC floor (rigid diaphragm), respectively. S3 is a two-story building with a nailed plywood floor. Each specimen is tested with increasing magnitude of earthquake loading. The shake table test results showed that the adopted design guideline is sufficient. At higher seismic loads, however, the prevalent plan irregularity induced higher torsional demand damage at the RC core and timb...

A Study on the Construction History of Kintai Bridge in Japan

The aim of this research is to present a structured and comprehensive history of the rebuilding process of the Kintai Bridge and also to analyze the building knowhow of this particular structure that has been passed down to generations of carpenters. A great part of the information was obtained from interviews with the carpenters that worked on the most recent rebuilding process and also on available historical materials, such as drawings and tools that were used in past rebuildings. This research analyzes the history of the bridge by dividing it into three distinguished periods. In the first period, the bridge is considered to have maintained its original design and as such; in the Heisei Era rebuild, carpenters decided to restore the Kintai Bridge to this original form using the earliest available drawings from the Genroku Era. During the second period, carpenters developed their own design templates and measuring units in the form of rulers to guide the rebuilding process. The last and third period covers the modernization of the bridge since the Shōwa Era rebuild (1950).

CLT panels in Japan from cradle to construction site gate: global warming potential and freight costs impact of three supply options

ABSTRACT This study investigates the effect of three different multimodal transport combinations for cross laminated timber (CLT) supply on global warming potential and freight costs from cradle to the construction site gate. It attempts to demonstrate to what extent a local approach could be beneficial, both environmentally and economically. It was found that emissions during the transportation modules will be more than those from the manufacturing stages in the case of intercontinental routes, contrary to the environment-friendly idea usually associated with timber products. Also, the results showed that it is crucial to locate CLT manufacturing facilities as close as possible to wood supply sources, in order to reduce the freight costs of low value-added products.

A STUDY ON THE ADHESION OF PLASTER IN LATH AND PLASTER CEILING

We conducted tension and shearing tests on lath and plaster ceiling in order to reveal the structural mechanism about the adhesion of plaster to wooden laths. In addition, we developed a mechanical model and a structural design formula for lath and plaster ceiling. Through the tests, it was found that whether plaster is pushed out to the rear of wooden laths or not, has the most important influence on the adhesion of plaster. We could develop the formula to accurately evaluate the strength of lath and plaster ceiling.

Outline of Investigation and Damage

On March 11, 2011, at 2:46 pm Japan standard time, a magnitude 9.0 earthquake struck off the eastern coast of Honshu, Japan’s main island, approximately 129 km east of Sendai. The earthquake and tsunami produced severe building damage and over 15,000 people were killed due to tsunami. This earthquake was later named “The 2011 off the Pacific coast of Tohoku Earthquake” by the Japan Meteorological Agency (JMA).

AN ANALYTICAL STUDY ON LARGE DEFORMATION STATIC BEHAVIOR CONSIDERING BREAKING JOINTS OF WOOD HOUSES

This paper attempts to predict analytically large deformation static behaviors of two story wooden frame walls from the static performances of members and joints which compose wooden frame houses and walls. Wooden frame walls in this study have fragile joints which need to consider repeated contact problems, therefore extended distinct element method (EDEM) are applied which can consider these problems.110 joint specimens are tested. They are pressed in axial side, bent inside and outside. From the results of these tests and the past researches, the two story wooden frame walls are modeled. Especially, because of the brace failure modes of pressing side, four kinds of models are proposed for each wooden frame wall. The comparison of the results between EDEM analyses and tests indicates, 1) in the range of assumed brace failure mode, proposed models can predict test results, 2) by considering brace models in detail, proposed models can reproduce test results precisely.

AN EXPERIMENTAL STUDY ON LARGE DEFORMATION PERFORMANCES OF WOOD HOUSES CONSIDERING THE BREAK OF JOINTS

This paper attempts to clear large deformation behaviors of two story wooden frame houses and to predict large deformation behaviors of two story wooden frame houses from the summation of static performances of two story wooden frame walls that compose those houses. 4 types of wooden frame houses and walls are tested. The comparison of the results between two story wooden frame houses and the summation walls indicates, 1) until 1/30-1/25rad. deformation of 1st story, the summation of walls can predict structural performances of two story wooden frame houses without the influence of joint type of the column or the existences of boards, 2) after 1/25rad. deformation of 1st story, the structural performance of the summation of walls become different from that ones because failure modes of brace in walls is different from those of houses.

STUDY OF PERFORMANCE OF GRG SHEAR WALL WITH AN OPENING

Interior wall has some small opening for ducts, switch boxes and sockets. Static loading tests were conducted to determine the influences of small opening upon the seismic performance of shearing wall. The shear wall consists of a gypsum-based material; glass fiber reinforced gypsum board (GRG). GRG board comprises a gypsum core that contains glass fibers, embedded and reinforced with non-woven glass fibers on surfaces thereof. The seismic performance of the interior wall with small opening was decreased about 90% compared with the wall with no opening. Possible proposals were made based on the results of static tests in a process of design and installation.