DSpace コレクション:http://hdl.handle.net/11133/24152024-03-19T12:43:53Z2024-03-19T12:43:53ZTiNi 形状記憶合金のサブループ負荷における変形特性および窒素イオン注入による疲労特性の向上武田, 亘平http://hdl.handle.net/11133/27342022-06-01T02:48:02Z2014-02-26T15:00:00Zタイトル: TiNi 形状記憶合金のサブループ負荷における変形特性および窒素イオン注入による疲労特性の向上
著者: 武田, 亘平2014-02-26T15:00:00ZQuantitative Analysis of Microstructure of Silicate Ceramics and its Relationship to Thermal Expansion PropertyKATAYAMA, Masakihttp://hdl.handle.net/11133/27322022-06-01T02:47:44Z2014-02-26T15:00:00Zタイトル: Quantitative Analysis of Microstructure of Silicate Ceramics and its Relationship to Thermal Expansion Property
著者: KATAYAMA, Masaki2014-02-26T15:00:00ZEXPERIMENTAL STUDY AND ANALYTICAL METHOD OF PARTIALLY CONCRETE-FILLED STEEL BRIDGE PIERS UNDER BI-DIRECTIONAL DYNAMIC LOADINGHuihui, Yuanhttp://hdl.handle.net/11133/27222022-06-01T02:47:31Z2013-09-11T15:00:00Zタイトル: EXPERIMENTAL STUDY AND ANALYTICAL METHOD OF PARTIALLY CONCRETE-FILLED STEEL BRIDGE PIERS UNDER BI-DIRECTIONAL DYNAMIC LOADING
著者: Huihui, Yuan
抄録: From past large earthquake, it has been recognized that the highway steel bridge piers in urban areas play a very important role in the social lifeline system. The seismic design specification of steel bridge piers introduced in the current Japan allows independent, longitudinal, and transverse forces. To date the seismic performance of steel bridge piers has been widely studied through static cyclic loading tests, pseudo-dynamic loading tests, and numerical analysis in a single lateral direction under constant axial force. However, the actual seismic waves consist of three-directional components and the seismic response of bridge piers is simultaneously affected by the two horizontal components. It is difficult to properly evaluate the seismic performance of bi-directional horizontal seismic motions through single-directional loading tests because of the complex behavior of local buckling and inelastic behavior caused in the component plates of the pier at the ultimate state. To clarify the seismic performance of partially concrete-filled steel bridge piers subjected to bi-directional seismic loading, the performance of partially concrete-filled steel bridge piers under actual earthquake conditions was investigated using 20 square section specimens through cyclic static loading tests and single-and bi-directional hybrid loading tests in this study. Three acceleration records of two horizontal NS and EW direction components in three different ground types, obtained during the 1995 Kobe Earthquake, were adopted during the dynamic tests. The experimental results clarified that the maximum displacement and residual displacement under actual earthquake conditions cannot be correctly estimated by conventional single-directional loading test results in medium and soft ground types, and the filled-in concrete can effectively improve the seismic resistance performance in sufficiently high concrete filled steel bridge piers. In this study, an analytical model consisting of a concentrated mass and a rigid bar with multiple springs located at the base was developed to simulate the hysteretic behavior of partially concrete-filled steel bridge piers subjected to single- or bi-directional ground motions. In order to describe the complicated nonlinear behavior of each spring element accurately, a series of approximate curves whose parameters were determined by results of single-directional static cyclic loading tests had been adopted. To examine the validity of the proposed model, the results due to the simulation were compared with those of static cyclic tests, single- and bi-directional hybrid tests. By comparison, it is demonstrated that the proposed multiple-spring model can predict well the hysteretic behavior of partially concrete-filled thin-walled steel bridge piers with square cross-section.2013-09-11T15:00:00ZCharacteristics of Strong Ground Motions and Fragility Curves of Buildings during the 2011 off the Pacific coast of Tohoku EarthquakeHao, Wuhttp://hdl.handle.net/11133/27212022-06-01T02:47:11Z2013-09-11T15:00:00Zタイトル: Characteristics of Strong Ground Motions and Fragility Curves of Buildings during the 2011 off the Pacific coast of Tohoku Earthquake
著者: Hao, Wu
抄録: The 2011 off the Pacific coast of Tohoku Earthquake was an Mw9.0 mega thrust interplate earthquake. It was the largest earthquake in Japan and the fifth largest one in the world since seismology records began in 1900. The coastal area, especially in the Iwate and Miyagi Prefecture, was subjected to great damage by huge tsunami. Many villages and towns including the buildings and people were entirely flushed away. Except the damage caused by tsunami, the ground shaking during this earthquake also brought about the damage to buildings over the east Tohoku and Kanto regions. It is essential to investigate the relationships between building damage ratios and ground motion characteristics, i.e., fragility curves, during this earthquake, which will be useful for disaster mitigation and damage assessment in future disastrous earthquakes. First, the relationships between building damage ratios in administrative districts, such as city, town and village (shi, cho, mura in Japanese), and observed ground motions during the 2011 Tohoku Earthquake are investigated. Three different damage ratios, i.e., total collapse ratio (TCR), collapse ratio (CR) and damage ratio (DR), are related to four ground motions indices, i.e., peak ground acceleration (PGA), peak ground velocity (PGV), JMA instrumental seismic intensity (IJMA) and spectral ratio (SI), respectively. However, the ground motions are sensitive to geological conditions in administrative districts, it suggests that the ground motions should be estimated within a smaller administrative unit, e.g., subdistrict (subdivision of an administrative unit), to be related to the damage ratios. Therefore, in this study, the method of estimating ground motions during the mainshock is proposed and verified. This method indicates that the ground motions at the sites where no strong motion stations were installed can be estimated with the underground velocity structures identified from the microtremor H/V spectral ratios and the ground motions at the bedrock during the mainshock calculated by use of the short-period source model. The underground velocity structures at damaged sites are identified from microtremor H/V spectral ratios. By applying the proposed method, the ground motions in subdistricts are estimated with the identified underground velocity structures and the bedrock motions during the mainshock. Fragility curves based on the damage ratios and estimated ground motions in the subdistricts of Osaki and Kurihara cities, and Wakuya town, Miyagi prefecture during the mainshock are then investigated.2013-09-11T15:00:00Z