| Co-Investigator(Kenkyū-buntansha) |
TAKABATAKE Hideo CHUBU UNIV., ENGIN.GRAD.SCH., PROF., 工学部, 教授 (20064462)
TANIMURA Sinnji CHUBU UNIV., ENGIN.GRAD.SCH., PROF., 工学研究科, 教授 (30081235)
HIRASAWA Ikuo CHUBU UNIV., ENGIN.GRAD.SCH., PROF., 工学部, 教授 (50065281)
MIMURA Kouji CHUBU UNIV., ENGIN.GRAD.SCH., PROF., 工学研究科, 講師 (70181972)
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| Research Abstract |
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 the resulting brittle type of structural failure. An international cooperative research has been carried out for three years since 1999, funded from Grant-in-aid for Scientific Research. Among, significant research results, the following is abstracted with special attention on main causes of characteristic failure undergone at Ashiyahama high-rise apartment complex and bridge piers in Kobe: 1.Governed by stress waves, the transient phase of structural response plays an important role, 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. 2.Actual severe damages were located near structural portions where abrupt changes, in energy transmission must have taken place. 3.Actual main rupture in the heavy steel skeleton occurred near such a location, and is understood as caused by this effect. 4.The particular large scale rupture experienced near a brace-column joint was initiated by the 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. These phenomena have been found from an exact three-dimensional finite element dynamic analysis.
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