Masahiro Inayama

DEVELOPMENT OF PARALLEL CHORD TRUSS USING PRE-CUT SYSTEM AND STANDARD SIZE TIMBER FOR RESIDENTIAL USE

Wooden trusses are effective method for constructing long span beams using standard size timber for residential use which is under six meters long. In this research, in order to create the standard drawings, the full-size bending test of parallel chord truss which took up three tree wood and was consisted by typical metal fittings and joints that can be produced by pre-cut system was carried out. As the results, it indicated structural property of each wood species and calculation formula to estimate the yield strength and the rigidity was established.

Evaluation of Shear Performance of Screw Joints Reinforced with Adhesives for Floor Joists

The practical method for evaluating improvement of the shear performance of floor joints to horizontal diaphragms was examined when using adhesives as compared to designs for screws alone, assuming that the design of the stressed-skin panel used Laminated Veneer Lumber (LVL) for both the flange and the web. The adhesive was spread around the screw joint, and single shear tests were done. Then the maximum loads, loads at yield point, and stiffness were compared to the condition with a gap in the shear plane and the condition of water soaking the test piece after curing. As a result, it became possible to calculate the reduction factor of the screw joint and the adhesive joint independently, and it became clear that evaluation of the condition with a gap in the shear plane is needed, to obtain the just appraisal for the design where adhesive is spread on the entire shear plane.

Pull-out Resistance Mechanism of Wari-kusabi Joints

Wari-kusabi Joints (Japanese traditional mortise-tenon joints with wedges) have been used as wooden structure joints in Japan. The pull-out resistance mechanism of the joint which connects post to beam was analyzed and modeled based on mechanical theory. The load-deformation curves in pull-out tests of mortise-tenon joints were influenced by resistance of compressive strain inclined to the grain and friction between post and beam. We proposed a mechanical model including these factors. The load-deformation curves in the elastic and plastic region could be estimated ; initial stiffness K, and yield point deformation δy were calculated by proposed design formula.

DEVELOPMENT OF WOODEN SHEAR WALL USING JAPANESE TRADITIONAL ELEMENTS

In this study, vertical cross piece made from hard wood was contained, the wooden shear wall composed of Japanese traditional elements was designed and the in-plane shearing test was done. The presumption of the moment resisting performance of the wall was tried by existing Inayama’s and Fukuyama’s formula. The stiffness, the yield load and the calculation value had good coincidence with the result of the test in the M-θ relation of each part, and it made it possible to presume on the safety side in the entire wall for the initial stiffness. The possibility of the wooden wall with high ductility and rigidity was shown by this development even if it did not rely on the steel hardware.

MOMENT RESISTING PERFORMANCE OF WEDGED AND HALVED SCARFED JOINTS, OKKAKE-TSUGI

Ph. D. Student, Grad. School of Agri. and Life Sci., The Univ. of Tokyo, M. Agri. **東京大学アジアセンター 特任助教・農博 Assist. Prof., ANESC., The Univ. of Tokyo, Dr. Agri. ***東京大学大学院 農学生命科学研究科 准教授・工博 Assoc. Prof., Grad. School of Agri. and Life Sci., The Univ. of Tokyo, Dr. Eng. � 写真1 �追掛継� 追掛継の曲げ性能 一方向鉛直荷重による弾性域の回転剛性評価式の提案 MOMENT RESISTING PERFORMANCE OF WEDGED AND HALVED SCARFED JOINTS, OKKAKE-TSUGI Proposal of rotational stiffness design formula in elastic region

IN-PLANE SHEAR TEST AND ANALYSIS OF MECHANICAL BEHAVIOR OF INSERTED WOODEN SIDING WALL

In this research, the authors carried out the in-plane shear tests for five types of the inserted wooden siding wall different in wall length, board width and board direction each other, and the effects of the differences in load deformation characteristics, deformation and destructive behaviors of the wall elements were revealed. In addition, this study proposed the calculation method for rigidity and ultimate strength of the inserted wooden siding walls depending on the mechanical model created by taking the differences into account. Comparing the estimation values with the test values of rigidity and ultimate strength in both of the whole wall and the elements, the validity of the calculation method were verified.

STUDY ON COEFFICIENT Bi IN N VALUE CALCULATION METHOD ABOUT COLUMN'S TOP AND BOTTOM JOINTS

According to the moment resistance frame substitution model, the assumed stress state about the N value calculation method to estimate the required tensile force of columns top and bottom joints was explained. The general solution about the tensile force of columns top and bottom joints was derived with the moment resistance frame substitution model and the shear panel substitution model in which the bending stiffness of the beams and the axial stiffness of the joints were considered. It was found by using the general solution with these substitution models that the coefficient “Bi”, which is multiplied by the shear wall magnification factor in N value calculation method, was affected by the bending stiffness of the beams and the shear wall length. As a result, the validity and coverage of the coefficient “Bi” became clear. In addition, the approximated values of “Bi” corresponding to each shear wall length were shown in Table 3 for the practical structural calculation as the result of this theoretical study. The tensile force of columns top and bottom joints in various conditions can be obtained accurately by the calculation method of this theoretical study.

PREDICTION AND ITS VERIFICATION OF THE ENVELOPE CURVE FOR ARBITRARY LENGTH MUD WALL FROM TWO KINDS OF WALL LENGTH WITH DIFFERENT FRACTURE MODE

The purpose of this research is to propose a method for the evaluation of the shearing performance of the mud wall based on the load carrying mechanism of the mud wall. It is confirmed by our current research that the fracture mode of the mud wall depends on its wall length. And the initial stiffness and the load bearing capacity of the mud wall is not proportional to the wall length. It is presented in this paper that the envelope curve of the mud wall which has an arbitrary wall length is interpolated between the envelope curves that have different fracture modes each other, and the validity of this prediction method was experimentally confirmed.

PROPOSAL AND VERIFICATION ON FORMULA TO EVALUATE REQUIRED TENSILE CAPACITIES OF CONNECTIONS AT COLUMN'S TOP AND BOTTOM FOR CONVENTIONAL POST AND BEAM STRUCTURAL SYSTEM CONSIDERING THREE DIMENSION EFFECT

In this paper, the formula to evaluate the required tensile capacities of connections at columns top and bottom for conventional post and beam structural system having sheathed walls with openings, which are extended assuming rigidity of beams and floors in three dimensional structures from one previously derived assuming rigidity of beams in plane structures by authors, is presented and experimentally verified.The formula to evaluate normal force of column consists of the sums of the dead normal force, the normal force caused from the over turning moment by the horizontal shear force acting on upper stories, and vertical shear force produced in the shear wall carrying the shear resistance. The formula has been verified by carrying experiments on a two story three dimension structure with 26 kind variables. Dividing three dimension effect into perpendicularly arranged columns and walls effect to loading direction, the generating mechanisms have been experimentally made clear. For the variable of the bending stiffness of beam, experiments clearly shown that the beam deformation could not been disregarded.