著者

藤原 悌三 佐藤 忠信 久保 哲夫 村上 ひとみ

出版者

京都大学防災研究所

雑誌

京都大学防災研究所年報. A (ISSN:0386412X)

巻号頁・発行日

vol.32, no.A, pp.71-95, 1989-04-01

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The earthquake we have investigated took place in the Nepal-India border region in the earlymorning on 21 August 1988. This earthquake in the southeastern zone of Nepal close to the bor-der of the State of Bihar, India registered 6.6 on the Richter Scale. Its focal depth was assumedto be 57 km. In Bihar State, India, 282 persons died, 3766 were injured and 150, 000 houses weredamaged. In Nepal, 721 persons died, more than 5000 were injured and 100, 000 houses weredamaged. Most the houses damaged had been constructed of stone cemented with mud mortar, unburnt bricks, or burnt brick masonry. There are many wooden houses and few reinforced con-crete buildings in the effected area. We did not find any serious damage to those structures.This is a survey report, in which the damage to human loss and the collapse of buildingstructures done by the earthquake are introduced and discussed. We estimated the fault zone ofthis earthquake from the post-earthquake records. The intensity of ground shaking around theeffected areas is discussed in terms of assumed fault parameters and the geological condition ofthe surface layer. We also prepared a questionnaire asking inhabitants. The intensity distribu-tion estmated from their information is compared with the intensity derived from seismographicdata. Based on our laboratory tests of sand specimens collected from riversides where liquefac-tion occurred during the earthquake, the maximum acceleration near the epi-center is also esti-mated. The strength of the structures in the effected areas is estimated and compared with theactual damage done. On the basis of our survey and analytical results we present some recom-mendations for the mitigation of earthquake disasters in these areas.

著者

黒田 満 倉賀野 哲造 久保 哲夫

出版者

一般社団法人情報処理学会

雑誌

情報処理学会論文誌 (ISSN:18827764)

巻号頁・発行日

vol.39, no.3, pp.602-609, 1998-03-15

参考文献数

14

被引用文献数

3

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曲率半径が弧長の折れ線グラフとなる滑らかな対数らせんスプライン補間曲線の導出法を提案している.曲線はスパン曲線長,与点での曲率半径と接線を未知数とする連立方程式を,パラメトリック3次のC2補間曲線からの良い初期値を使ってニュートン・ラプソン法で解いて導く.提案手法は計算機援用の形状設計に有用な次の特長を持っている.(1)弧長,接線,曲率半径といって,設計者の直観になじむ幾何情報だけから形状を設計・制御できる.(2)縮閉線がまた対数らせんスプライン曲線となるし,オフセット曲線と伸開線も対数らせんスプライン曲線で精度良く近似できるので取り扱いやすい.(3)必要なら,導出曲線を許容誤差範囲内で有理多項式近似できる.さらに,クロソイド弧の挿入による変曲点の導入や1スパンを複数曲線分化して表現力を強化する拡張法についても簡単に述べている.This paper presents a method for constructing an interpolating smooth curve composed of logarithmic spirals,whose radius of curvature is piecewise linear with respect to arclength.Using good initial values from the conventional cubic C2 interpolant,the curve is obtained by the Newton-Raphson method from a system of equations whose unkowns are arclengths of spans,tangents and curvature radii at data points.The method has the following three features for computer aided geometric design.(1)It specifies and controls shape of curve by intrinsic geometric quantities familiar with designers,such as arclength,tangent and radius curvature.(2)Its evolute is also expressed by logarithmic spiral splinecurve,and its offset curve and involute are approximated very well by logarithmic spiral spline curve and hence these associate curves are easy to deal with.(3)The derived cruve might be approximated within a tolerance by conventional rational polynomials,if necessary.Extensions of the method are described for introducing an inflection point by use of a clothoid segment and for making the curve more flexible by multi segments per span.

著者

久保 哲夫

出版者

一般社団法人日本建築学会

雑誌

建築雑誌 (ISSN:00038555)

巻号頁・発行日

vol.113, no.1423, pp.28-29, 1998-06-20

被引用文献数

2

著者

久保 哲夫

出版者

東京大学

雑誌

基盤研究(B)

巻号頁・発行日

2009

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最大加速度値の大きな強震地震動の動特性と高加速度の地震動が建築構造物に入力する際の時間差を考慮した場合の時間差に対する応答の変動について、高加速度強震地震動データベースを作成し、数値解析によって弾性・弾塑性の応答の低減効果を定量的に評価した。大きな最大加速度を有する地震動は短周期成分が卓越する傾向を有すること、ならびに建築構造物の応答では入力の時間差を大きく取るほど応答が低減する傾向が認められた。

著者

中埜 良昭 西谷 章 瀬谷 均 平田 京子 神田 順 久保 哲夫 大井 謙一 称原 良一 桑原 文夫 平嶋 義彦 1999年度日本建築学会設計競技(技術部門)審査委員会 高梨 晃一

出版者

一般社団法人日本建築学会

雑誌

建築雑誌 (ISSN:00038555)

巻号頁・発行日

vol.114, no.1441, 1999-07-20