スギ材の利用拡大を目的に,スギ材をそえ心材に利用したの製造試験を行なった。製造試験は,単板製造の最大の難関である単板切削工程と乾燥工程を中心に検討した。単板切削工程では単板歩留りは70%以上を得ることができた。乾燥工程は,自動制御型のドライヤーを使用し,暴れ現象を減少させ,仕上がり含水率8%程度の単板を製造することができた。強度試験はJAS2級に準じて行った,合格率は100%であった。このことから,スギ材の利用が十分可能と判断された。今後の課題としては,スギ材の素材生産・集荷体制の整備が必要と考えられる。また,スギ材価格は,競合する外材との価格差解消のための何等かの政策が必要と考えられる。

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 Several studies based on structural properties of plywood walls and wooden semi-rigid frames have been conducted. However, the complex behavior of a wooden semi-rigid frame composited with structural plywood has made it difficult to establish its structural design method. The wooden semi-rigid frame joint has the problem of displaying semi-rigid performance. Therefore, it is difficult to satisfy the necessary stiffness of 1/120 radian, which is the limit value of the deformation angle in the elastic design of buildings. In this case, it is possible to compensate for the initial stiffness by incorporating a structural wall into a wooden semi-rigid frame. In general, an independent wall framework is set up within a wooden semi-rigid frame. A plywood board is nailed onto this framework. If it can be nailed directly onto the columns of the semi-rigid frame, there is no need to place a post in the framework, and the designing process can be more cost-effective.
 Due to the complex behavior of the wooden semi-rigid frame composited with structural plywood, the structural design method cannot be established. This study aims to clarify the properties of the wooden semi-rigid frame with structural plywood with tests and build its structural design method.
 A wooden semi-rigid frame with a lag-screw-bolt (LSB) for the joints was used in this study. The structural properties of the semi-rigid frame with structural plywood were estimated by conducting static racking tests for four types of specimens. The four types of specimens were as follows: “Rigid” wooden semi-rigid frame; “Outside” wooden semi-rigid frame with a structural plywood wall nailed on the outside edge of the column; “Inside” wooden semi-rigid frame with a structural plywood wall nailed on the inside of the column; and “Wall-O” and “Wall-I” structural plywood wall only.
 Nuts were used to fill the empty 20 mm. The structural models of these specimens were simplified. At the bottom of each LSB, load cells were installed to measure the tension side axial force.
 We examined the following: the shear-rotational angle curves of the wooden semi-rigid frame of “Outside”, where “Inside” was determined from the supporting point reaction; the shear-rotational angle curves of the plywood wall of “Outside”, where “Inside” was found by taking the load-rotational angle curves of “Wall-O” or “Wall-I”. The tests showed that there is a certain difference in the shear-rotational angle curves subjected to the nail position.

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Recently, the numerical value and the technical information of the design are insufficient though an increase of a large timber construction is expected. In this research, a high load carrying capacity shear wall with thick plywood sheathings for the large timber construction was developed, and its static bearing force was confirmed experimentally. And the bearing force of the shear wall was calculated by using past numerical analysis methods. As a result, the development of the wall having the target bearing force succeeded, and the numerical analysis method could be applied to the high load carrying capacity shear wall.

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One of key issues of recent seismic structural design for buildings is the safety performance against long duration earthquake, repeated earthquake and severe earthquake after main shock. It may be difficult for conventional shear walls of wood house such as bracing and plywood shear wall to survive during their earthquake.
In this study, shear wall with high stiffness rubber was proposed to prevent the degradation of seismic performance during repeated earthquakes and shear wall test and shaking table test were conducted in comparison with plywood conventional shear wall.
Following results were obtained:
1 In shear wall test, it was found that no degradation occurred in proposed shear wall in the range of 1/30rad.
2 In shaking table test, the specimen without proposed shear wall was damaged in three times severe earthquakes, while the specimen with it was survived in five times severe earthquakes.

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Recently, medium large scale wooden buildings have became popular. Large rooms are often located in these buildings such as auditoriums, conference rooms and so on. In order to create these rooms, it is required to develop Stressed-Skin Panels (SSP) which support long span floor. The purpose of this study is to clarify the bending performance of SSPs. Bending performance of SSPs depends on tensile strength and stiffness of their flanges. For this reason, tensile tests of plywood used as flanges are conducted and plywood with the best properties are selected. After that, full size bending tests of SSPs are carried out to measure bending performance and the validity of the evaluation method was verified.

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Long spanned box beams constructed by standard timber of Japanese conventional housing and sheathed with structural panels are useful to construct medium and large scale wooden structures, but creep deformation tend to increase compared to single lumber beams. Therefore it is important to reduce initial deflections. In this study, full-size bending tests of several types of box beams are conducted to evaluate their utility by analyzing initial deflections and fracture behavior.

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In this study, the limit curve relating between energy absorption and maximum displacement is derived from cyclic loading test of wood shear walls. Time-history analysis is also conducted to evaluate safety of wood shear wall based on the limit curve. As the results, following conclusions are obtained:
1) Limit state derived from energy absorption and maximum displacement of wood shear wall is similar to that of steel members. That means limit state is determined by energy absorption index.
2) The state mentioning above is slightly different from types of shear wall. Characteristic of sheathed shear wall such as plywood shear wall is close to steel member but that of bracing shear wall is close to medium characteristic of steel and reinforced concrete member.
3) According to results of time history analysis, responses which are designed in accordance with minimum requirement of Japanese building standard law transcend the limit state during extremely big earthquakes such as JMA Kobe and JMA Kawaguchi.
4) Aftershock should be considered in seismic performance for shear walls which is sensitive to energy absorption.

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In this report, the decision making tools for choosing seismic reinforcement method of old wooden house is proposed. The tools evaluate the aseismic performance, cost, ease of construction and visual quality. The evaluated methods of reinforcement are nine newlyproposed method and four traditional method. All newly-proposed methods get certified from the Japan Building Disaster Prevention Association and the four traditional methods contains the method using plywood with opening for more convenient works. The proposed tools can help a rational decision for both structural designers and house owners, and can promote the aseismic reinforcement of old wooden house.

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The study deals with the damage control system of wooden houses using wood friction-based dampers subjected to earthquake motion. In this study, wood friction joints were developed to introduce damping into wood shear walls. Shaking table tests were also conducted to investigate the seismic performance of two-story timber structures composed of plywood shear walls, plasterboards and timber shear walls using high damping devices. The purpose of this study is to propose an estimation method of the required quantity of the friction damper to satisfy the restriction value of the story drift angle for the continued use after earthquake motion.

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 Earthquake damage estimation after a major earthquake is important for prompt rescue. We developed a hysteresis characteristics model for existing wooden houses that can reproduce actual behavior under large displacement for earthquake damage estimation. We conducted the shaking table tests of wooden houses with different strength and input ground motions in order to get experimental results used in the seismic response analyses.
 The types of shear walls and the amount of shear walls varied series were conducted. The specimens of each series were shaken at the same time. The input ground motions were the K-NET Anamizu, the K-NET Hiroo, and the simulated earthquake motion. The K-NET Anamizu recorded in the 2007 Noto-Hanto earthquake has large 1-1.5 sec. responses which have close relationship with heavy damage to wooden houses and buildings. The K-NET Hiroo recorded in the 2003 Tokachi-Oki earthquake is very short period of 0.2 sec dominated motion. The simulated earthquake motion (phase: El-Centro NS) is period of 0.4 sec dominated one, the type of which has never been recorded. The result that the displacement of the specimens increased as the strength decreased was found under the K-NET Anamizu. Buckling of a brace and a damaged nail were seen in the specimens with low strength. The displacement of all specimens were small and they were not damaged under the K-NET Hiroo. The unusual result that the displacement of the specimens increased as the strength increased was found under the simulated earthquake motion in contrast under the K-NET Anamizu. This is because the natural period becomes shorter as the strength increased in wooden houses.
 We tried to reproduce the experimental results by seismic response analyses. We used the modified Takeda-Slip model for wooden houses as a hysteresis model. We modified the hysteresis characteristics model as follows:
 (1) Modification of the formula of unloading stiffness
 (2) Consideration of deterioration under cyclic load
 (3) Consideration of the asymmetrical behavior in the case of plywood We could reproduce the experimental results accurately by the modified model.

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昭和55年建設省告示第1791号第2によると，鉄骨造の筋かい架構のβ割増しについて，「地震応答解析結果によれば，筋かいの強度が混合構造体の強度の大略70%以上となると筋かいの荷重-変形関係の特徴が極めて強く出てくる」ことから「筋かいの強度を増加することによりエネルギー吸収性能をラーメン構造のそれに近づける」ために地震時応力を最大1.5割り増す，とされている．木造建築物の筋かい架構にも，同号第1で同様の規定に適合することが求められているが，応力割増し係数については合理化の余地があると考えられる．そこで本研究では，異なる仕様の筋かい耐力壁を用いた地震応答解析を行い，

の応力割増し係数に対する筋かいの種類に応じた適切な応力割増し係数を提案することを目的とする．

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Stressed-skin semi-monocock structures are often used for the light structures such as aircraft airframe components. In these structures, the stresses are carried not only by the framing members but also by the surface membrane. There has recently been increasing use of moment resisting glulam timber joints in building structures. However, these joints require relatively large cross-sections because the moment resistance is carried by only the linear elements. This is not only uneconomical but also unattractive. Bending experiments on panel joints were carried out. This paper has proposed moment resisting timber joints using stressed-skin effect. It has also presented equations for estimating the rotational rigidity and the maximum strength of the joints, and demonstrated their prediction capability with sufficient accuracy. It has been shown that a frame with a smaller cross-section than that of only rib members is achievable with this joint.

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木質系面材が表面に張られた枠組壁工法の壁の耐火性を検討するため, 木質系面材の仕様をパラメータとして実大規模の壁耐火試験を実施した。試験体の構成は加熱側から木質系面材, 通気層・胴縁, , 中空層・たて枠, 普通石膏ボードである。試験体により木質系面材の樹種・難燃処理・厚み・張り方をそれぞれ変化させている。本試験の結果, 主に以下の知見が得られた。（1）木質系面材の裏面温度は260°C程度で急激に温度上昇した。（2）木質系面材の樹種, 張り方による木質系面材裏面温度の顕著な差異は見られなかった。（3）表面が260°Cに到達する時間は木質系面材裏面に比べ1～4分程度遅れる傾向にある。

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Wood grid walls are widely used as a seismic-load resisting element for upgrading traditional Japanese wood structures. However, because the elements are expected to be joined loosely due to unavoidable drying shrinkage, the current design provisions attribute small initial stiffness to grid walls. Consequently, an experimental study was conducted to examine how the seismic performance of grid walls may be improved by the use of compressed wood. Compressed wood has shape recovery behavior by compression under low temperature. These elements can be used to overcome the stiffness reduction of wooden interlocked joints caused by drying shrinkage.

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To clarify the failure mode, the shear strength and the deformation capacity of the mortar finishing external wall which constructed by ventilation method, static shear loading tests of the specimens with 910mm of wall length were conducted. The maximum shear strengths of the specimen with orthogonal walls and the one with a plywood as a shear wall were remarkably high. The maximum shear strengths during the tests were observed at from 1/75 rad to 1/30 rad, and the shear strengths disappeared over approximately 1/20 rad. However, the mortar layer did not fall off.

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A series of sheathed timber-framed walls finished with wood are designed and verified against fire resistance tests for the development of 1-hour Quasi-fireproof construction suitable for large scale timber buildings. The results reveal feasibility of designs with noncombustible underlayer thinner than conventional rated designs and insignificance of seismic effect on the fire resistance of the tested designs.

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