MEASURES TO COPE WITH IMPULSIVE EFFECT OF NEAR-SOURCE EARTHQUAKE IN STRUCTURAL TRANSIENT RESPONSE

结构暂态响应中应对近源地震脉冲效应的措施

• 批准号: 11355025
• 负责人: NONAKA Taijiro
• 金额: $ 24.18万
• 依托单位: CHUBU UNIVERSITY (2000-2002)Kyoto University (1999)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11355025/
• 关键词: IMPULSIVE; RUPTURE; WAVE; EARTHQUAKE; STRUCTURE; TRANSIENT; 兵庫県南部地震; 木造家屋; 跳び石; 耐震設計; 衝撃解析; 脆性破壊; 地震被害; 波動伝播解析; 動的設計法

Structural damage suffered from the 1995 Hyogoken-nanbu Earthquake (Kobe Earthquake) motivated the authors to initiate investigation into the quasi-impulsive effects of near-source earthquakes and to establish structural measures to cope with them. A cooperative research has been carried out involving various academic fields for four years since 1999, funded from Grant-in-aid for Scientific Research. Among significant research results, abstracted are the following :(1) The field surveys and rupture process observations of recent earthquakes have revealed that in Quindio earthquake, a large rupture occurred after a small initiation, and the big shake caused by the second event struck Almenia city, killing over 1000 people ; in Kocaeli earthquake, which killed over 30000 people, an earthquake fault appeared over a length of 100km, causing a maximum horizontal acceleration of 407gal and maximum vertical acceleration of 260gal near the fault ; in western Tottori earthquake, two clear phase … More s were identified, suggesting that the first rupture did not grow up continuously, but another big rupture succeeded later, indicating that shear stress might be completely and spatially released by large complex rupture around the second event. An earthquake"bright spot", proposed by Umeda, must have formed in a small confined region.(2) 3D dynamic finite-element simulation analyses have shown that the transient phase of structural response plays an important role, governed by stress waves, affecting heavily the following vibratory phase response, and possibly causing subsequent significant damage, in the case of severe earthquakes such as a near-source earthquake. The degree of this importance depends on ground-motion profile, site conditions and structural properties, such as shape, size, boundary or support condition, etc.(3) Actual severe damages in the Kobe earthquake were located near structural portions where abrupt changes in energy transmission must have taken place, with main rupture observed in heavy steel skeletons coinciding with such a location, and is understood as caused by this effect.(4) A particular large scale rupture experienced near a brace-column joint was initiated by brace breakage, which was caused by the combination of a great tensile axial force and transverse shear, and was transmitted to the adjacent column cross-section, which resulted in complete rupture.(5) Concentration of yield-hinge occurrence in a coincident story can cause severe whole story collapse. This is particularly dangerous, when occurred in an early phase of structural response to an earthquake.(6) In order to restrengthening an earthquake-damaged wooden house, a device of installing out-door metal poles together with bolted connections on the second floor level has been introduced, and found to be effective, transmitting horizontal resisting forces between the wooden frame and the poles, through experiment and earthquake response analyses.(7) As a result of Sharpy tests with varying speeds on steel specimens, it has been found that absorbable energy, and hence, fracture toughness also increase, as impact speed increases.(8) Sharpy tests have revealed that prestraining plays an important role in causing brittle failure of steel, and that plastic prestrain causes significant drop in absorbable energy capability. Less

1995年兵库县南部地震（科比地震）造成的结构破坏促使作者开始研究近源地震的准脉冲效应，并建立结构措施来科普它们。自1999年以来，在科学研究补助金的资助下，开展了四年涉及各个学术领域的合作研究。（1）对近期地震的现场调查和破裂过程观测表明，金迪奥地震是先小震后大震，第二次大震袭击了阿尔梅尼亚市，造成1000多人死亡;在造成3万多人死亡的科贾埃利地震中，出现了一条长达100公里的地震断层，在断层附近引起最大水平加速度407 gal和最大垂直加速度260 gal，鸟取西部地震有两个明显的震相 ...更多信息 这表明第一次破裂并不是连续增长的，而是随后又发生了一次大破裂，说明第二次地震前后的大的复合破裂可能在空间上完全释放了剪应力。梅田提出的地震“亮点”一定是在一个小的封闭区域内形成的。(2)三维动态有限元模拟分析表明，结构响应的瞬态阶段起着重要的作用，由应力波控制，严重影响随后的振动相响应，并可能导致随后的重大损害，在严重地震的情况下，如近源地震。这种重要性的程度取决于地震动剖面、场地条件和结构特性，如形状、尺寸、边界或支承条件等。(3)在科比地震中，实际的严重破坏位于能量传输发生突变的结构部分附近，在重型钢骨架中观察到的主要破裂与这种位置一致，并且被认为是由这种影响引起的。(4)其中一个支撑柱节点附近的大规模破坏是由支撑在轴向拉力和横向剪力的共同作用下发生断裂，并传递到相邻的柱截面上，最终导致完全断裂。(5)屈服铰集中出现在重合层中会导致严重的全层倒塌。这是特别危险的，当发生在结构对地震反应的早期阶段。(6)本文介绍了在二层水平安装室外金属柱和螺栓连接的加固方法，通过试验和地震反应分析，证明了这种方法在传递木框架与金属柱之间的水平抗力方面是有效的。(7)作为在钢试样上以不同速度进行的Sharpy试验的结果，已经发现，随着冲击速度的增加，可吸收能量以及因此断裂韧性也增加。(8)Sharpy试验表明，预应变对钢的脆性破坏起重要作用，塑性预应变使钢的吸能能力显著下降。少

项目成果

野中泰二郎: "軸方向速度入力を受ける弾塑性棒の応力波伝播特性"(続)兵庫県南部地震における構造物の衝撃破壊に関するシンポジウム. 論文集. 83-86 (2000)

Yasujiro Nonaka：“受轴向速度输入影响的弹塑性杆的应力波传播特性”（续）兵库县南部地震期间结构冲击失效研讨会 83-86（2000 年）。

内田一義, 武田幸和, 河西良幸, 堀越清視: "既存木造家屋の外部補強耐震工法-補強前後の地震応答性状"日本建築学会技術報告集. 第15号. 109-114 (2002)

内田和佳、武田幸和、葛西佳之、堀越清：《既有木结构房屋外部加固的抗震加固方法——加固前后的地震响应特性》日本建筑学会技术报告第15.109-114号（2002年）。

Tadokoro, K., Ando, M., Umeda, Y.: "S wave splitting in the aftershock region of the 1995 Hyogo-ken Nanbu earthquake"J. Geophys. Res. vol.104. 981-991 (1999)

Tadokoro, K.、Ando, M.、Umeda, Y.：“1995 年兵库县南部地震余震区的 S 波分裂”J.

Tanimura, S., et al., Edited by Khan, A.S. and Lopez-Pamies, O.: "Recently Developed Techniques and Specimen Geometries for Dynamic Response Studies, Plasticity, Damage and Fracture at Macro, Micro and Nano Scales"Proceedings of PLASTICITY '02, Aruba, Nea

Tanimura, S. 等人，Khan, A.S. 编辑

谷村真治: "鋼製薄肉円管の連続塑性座屈に関する研究"日本機械学会論文集A編. 66・642. 382-389 (2000)

Shinji Tanimura：“薄壁钢圆管的连续塑性屈曲研究”，日本机械工程学会会刊，A版66・642（2000年）。