Research and Developments for Enhancing Seismic Performance of Wooden Dwelling Houses in Recent Japan

第73回生存圏シンポジウム 生存圏科学ミッションの海外展開に向けて “2nd RISH-LAPAN-LIPI International Symposium, Science for Sustainable Humanosphere — International Collaborative Programs in Indonesia”, 2007 July 25, LAPAN, Bandung, Indonesia

Evaluation of Fracture Toughness for Wood-Epoxy Adhesive System under External Shear Force

この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました。Fracture Toughness G_c of Wood-Epoxy adhesive system under external shear force was evaluated by employing the experimental compliance method based on the Griffith-Irwin fracture theory. Invariability of G_c with the different glue line length was tolerably recognized and the representative value of G_c for the above system was about 0.25 (cm・kg/cm^2) throughout the series of glue line thickness tested. Fracture mode and stress distribution were discussed with some helps of Finite Element Method

<Original>Effect of Nail Pitch on the Shear Performance of Nailed GLT-plywood Specimens

この論文は国立情報学研究所の学術雑誌公開支援事業により電子化されました。Nails, used without predrilling holes in the wood, prevent the decrease of slip modulus by their clearance at the predrilled hole as like bolt fastening. For the purpose of investigating the effect of nail pitch on the shear properties of nailed plywood-sheathed glued laminated timber (GLT) specimens. Double sided single shear tests were conducted by varying nail pitch from 50, 75, 100mm, and to 150mm. The slip displacements measured at three different place, i.e. upper, bottom and center, were almost same. It was concluded from this experiment that the slip modulus were not affected by the nail pitch and showed that there were big dispersions on the observed values. The yield strength showed constant values despite of nail pitch. The maximum strength increased slightly as the nail pitch increased. Judging from these experimental results, it might be concluded that the effect of nail pitch on the shear performance of nailed plywood sheathed GLT specimen could be ignored, thus from the practical point of view, nail pitch has no significant effect on the design calculation

Mechanical performances of finger jointed cross laminated timber (CLT)

Based on the idea of first producing small-size CLT panels and afterward connecting them using finger joints to make larger CLT panels, finger-jointed CLT test specimens were fabricated by setting experimental parameters such as the kind of finger joint (large or normal), the combination of finger joint strength (strong–strong, or weak–weak) and the number of layers, and ply (3L3P, 5L5P, and 5L7P). Destructive tests subjected to out-of-plane as well as in-plane bending and shear, and axial compression load were performed. To judge the mechanical performance of the finger-jointed CLT panels, the lower 5% strength value evaluated from the destructive tests data were used for comparison with the characteristic strength value of CLT products assigned by the Ministry of Land, Infrastructure, Transport and Tourism in Japan (MLIT). On the other hand, the lower 50% stiffness value evaluated from the destructive test data was used for comparison with the design stiffness values proposed by commercial sectors. Most of the tested finger-jointed CLT groups satisfied the requirements for the characteristic strength values although there were a few exceptional cases in the weak–weak groups. All of the tested finger jointed CLT groups satisfied the proposed design stiffness values

Ronkin/Zeta Correspondence

The Ronkin function was defined by Ronkin in the consideration of the zeros of almost periodic function. Recently, this function has been used in various research fields in mathematics, physics and so on. Especially in mathematics, it has a closed connections with tropical geometry, amoebas, Newton polytopes and dimer models. On the other hand, we have been investigated a new class of zeta functions for various kinds of walks including quantum walks by a series of our previous work on Zeta Correspondence. The quantum walk is a quantum counterpart of the random walk. In this paper, we present a new relation between the Ronkin function and our zeta function for random walks and quantum walks. Firstly we consider this relation in the case of one-dimensional random walks. Afterwards we deal with higher-dimensional random walks. For comparison with the case of the quantum walk, we also treat the case of one-dimensional quantum walks. Our results bridge between the Ronkin function and the zeta function via quantum walks for the first time.Comment: 19 pages. arXiv admin note: substantial text overlap with arXiv:2202.05966; text overlap with arXiv:2109.07664, arXiv:2104.1028

Estimation of The Mechanical Properties of Mud Shear Walls Subjecting to Lateral Shear Force

[The 11th International Conference on Non-conventional Materials and Technologies (NOCMAT 2009)] 6-9 September 2009, Bath, UKIn this study, load-deformation relationship of mud shear wall (MSW) was assumed as a combined one which composed of non-linear semi-rigid frame action and non-linear solid wall action. In order to establish mechanical models, at first moment-rotation relationship of “Nuki” joint and mortise-tenon joint were theoretically derived. Then stress-strain relationship of solid mud part with bamboo laths was estimated by truncating load-deformation curve of frame only from that of full MSW. Finally, every data were inputted into non-linear FEM program to analyze three different MSW specimens. In the case of normal MSW, effect of frame was small, while in the case of hanging wall type MSW, the effect of frame joints was remarkable, especially in post yielding range

Experimental and Analytical Investigation on the Nonlinear Behaviors of Glulam Moment-Resisting Joints Composed of Inclined Self-Tapping Screws with Steel Side Plates

Glulam moment-resisting joint composed of inclined self-tapping-screws (STS) with steel side plates were designed and its nonlinear moment-rotational skeleton curve was predicted by taking nonlinear load(P)-deformation(u) relationships of all moment-resisting components into considerations within step-wise linear calculation process. P-u relationships of all moment-resisting components were estimated by the fundamental shear joint tests or appropriate empirical relationships and they were approximated by the tetra polygonal-line curves or bi-linear curves. The extended Normalized Characteristic Loop (NCL) model, which was originally developed for RC construction, was applied to describe the hysteresis loops. For predicting failure load, the design equations for a mechanical joint loaded with inclination to the grain direction were applied. Three replications of T-shaped beam-column joint specimens were fabricated using Canadian spruce glulam beam and column. Connections of steel plates to glulam members were all composed of full-threaded inclined-STS. Static push-pull cyclic loading tests were conducted and observed behaviors were compared with step-wise linear calculation results. Agreements between predicted nonlinear behaviors and observed ones were good on the whole

Evaluation on dynamic performance of glulam frame structure composed of slotted bolted connection system

World Conference on Timber Engineering (WCTE 2014), Quebec City, Canada, 10-14 August 2014.Earthquake-resisting performance of glulam frame structure was evaluated by shaking table tests on a specially designed glulam “double cross shape” specimen composed of slotted bolted connection (SBC) system. By the first vibration test using sinusoidal wave having a maximum acceleration of 800gal, the specimen survived until 80% level of input waves without damage. After renewing SBC system, the second vibration test was done on a same specimen using the JMA-Kobe NS waves having a PGA of 818gal. The specimen survived until 80% level of input without damage but slightly failed by the panel-shear when 100% level was inputted. Earthquake-resisting performance of glulam moment-resisting joints composed of SBC system was considered as satisfactory enough for ductile joint system, but improvement of panel-shear of glulam member itself was recognized as a future research need

A Smartphone Application as a Telemedicine Tool for Stroke Care Management.

Since smartphone applications are revolutionizing telemedicine, a new application specifically for stroke care (JOIN) was designed. Addition of the JOIN smartphone application to the stroke treatment workflow in our hospital was assessed. JOIN has key functions that may improve the care of stroke patients, including the ability to (1) exchange information such as patient data and medical images in real-time throughout the entire process of patient management; (2) track each step of the protocol from door to discharge; and (3) facilitate real-time interaction of all team members via text, audio, and a video chat system. Two periods, 2.7 years before the implementation of JOIN (Pre-JOIN) with 37 patients and 2.2 years after (Post-JOIN) with 54 patients, were compared, and the workflow for all 91 patients who had a cerebral infarction and were treated with tissue plasminogen activator (tPA) and/or thrombectomy between October 2012 and July 2017 was reviewed. There were noticeable reductions in overall patient management time, including times for door-to-imaging, starting tPA treatment, and endovascular intervention with JOIN. Staff members were unanimously satisfied with JOIN, due to the increased efficiency of information exchange and the ability for real-time discussions with different professionals when needed. No significant changes in patient outcomes (as assessed by modified Rankin Scale [mRS] scores) at 3 months and in the total cost for the treatment were observed. A smartphone-based application with the capability of sharing information instantaneously among healthcare professionals facilitated time-sensitive, acute care of ischemic stroke patients