52宮本 慎宏既存木造学校校舎の耐震性能評価法の構築 63Mitsuhiro MIYAMOTO山崎 義弘64Yoshihiro YAMAZAKI(2014年採択)Development of Seismic Performance Evaluation Method for Existing Wooden School Building (Project 2014)古い木造住宅の倒壊防止を目的とした柱脚滑り機構による革新的耐震改修法 (2014年採択)Innovative seismic retrofitting method for old timber houses by sliding machanics of columns (Project 2014)木造学校校舎は数少ない大規模木造建物として木造技術史の中で貴重な建物である．文化財的価値を有する木造学校校舎の安全性確保や保存活用のために，木造学校校舎の耐震性能評価法や耐震補強法を構築することが求められている．本研究では，木造学校校舎の耐震性能を把握し，建物の文化財的価値を考慮した効果的な耐震補強法の構築を目的とする．まず，木造学校校舎の主要な耐震要素である方づえ，筋かいを含む木造軸組架構のフレームモデルを構築し，既往の実験結果との比較からその妥当性を検討する．次に，愛媛県八幡浜市に現存する川之内小学校を対象として現況調査を行い，建物全体の耐震性能評価や耐震補強法の検討を行う．Wooden school buildings are valuable in the history of wooden structure technique as a few large-scale wooden buildings. For ensuring their seismic resilience, their preservation and application, it is important to evaluate their seismic performance and to propose their seismic reinforcement methods. This study set out to determine the seismic performance and to propose the effective seismic reinforcement methods considering the values as cultural properties. At first, the analysis models of wooden frames including the post-beams and braces are proposed, which are main seismic elements for wooden school buildings. Compared with the past test results, the accuracy of analysis models is examined. Secondly, the site investigations for Kawanouchi elementary school existing in Yawatahama City, Ehime Prefecture are conducted, and its seismic performance and seismic reinforcement method are examined.古い木造住宅を耐震補強する際，住宅南面の開口を保持するために補強箇所が限定されたり，健全な基礎が無いために高耐力の耐力壁を新設できないなどの課題に直面することが多い．本研究では，これらを解決し，かつローコストで行える補強方法として，建物の一部分の柱脚を滑らせる方法を取り上げ，その地震時挙動や性能改善のための方策を検討した．平面内における耐力壁の剛性バランスだけでなく，水平構面の面内剛性や平面形状も重要なパラメータとなる．柱脚滑り部では摩擦によりエネルギーが消費され，その局所的な減衰が建物の全体性能におよぼす影響も議論し，地震応答の低減に効果があることを示した．When seismic retrofit is applied to a wooden detached house, we often face some problems: a restriction of the place where additional components can be attached due to architectural reason, a restriction of the strength of additional components due to the weak foundation. In this paper, a low-cost seismic retrofitting solution is discussed. The method utilizes sliding of a part of the building on the foundation. Improvement of torsional vibration and supplemental damping by sliding can be expected. Not only the stiffness balance in the plan but shear stiffness of horizontal diaphragm are important from a point of view of seismic response reduction. The effect of local damping derived from energy dissipation by sliding to global damping ratio and the seismic response is also discussed.
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