Relative displacement response spectra with pounding effect     

Anat Ruangrassamee  Kazuhiko Kawashima 《地震工程与结构动力学》2001,30(10):1511-1538

To avoid unseating of a deck, an adequate seat width must be provided. The seat width is basically determined from maximum relative displacement between two bridge segments. Under a strong ground excitation, pounding between two decks may occur at a joint. The pounding will affect the response of two bridge segments. This research is conducted to investigate the effect of pounding on the relative displacement between two adjacent bridge segments. A simplified analytical model of two linear single‐degree‐of‐freedom systems is employed. To take into account the pounding, the laws of conservation of momentum and energy are applied. The analytical results are represented in the form of relative displacement response spectra with pounding effect. It is found that due to the pounding the relative displacement can be amplified, resulting in the requirement of a longer seat width to support a deck. The formulation of normalized relative displacement response spectra is presented together with an application example. It is found that the seat width determined from the relative displacement response spectra with pounding effect becomes close to the value specified in the Japanese design specifications for structures with large difference of natural periods. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

Miocene pillowed sills in the Shimane Peninsula, SW Japan     

Kazuhiko Kano 《Journal of Volcanology and Geothermal Research》1991,48(3-4)

Two Miocene basaltic andesite pillowed sills in the Shimane Peninsula, SW Japan, were intruded into wet marine sediments, plastically deforming them. The pillows are elongated, constricted, interconnected and relatively closely packed. Individual pillows have a poorly to moderately vesiculated, somewhat crystalline rind thinner than a few centimeters and a moderately to well vesiculated, more crystalline core; contraction cracks and spreading cracks are poorly developed. The pillows in the sills morphologically resemble pillow lava flows, and during sill intrusion, the magma bifurcated into pillow lobes in a manner similar to pillow lavas. Formation of pillows in sill probably occurs when the magma is intruded into wet sediments and protrudes fingers by the instability of the magma-sediment interface with little turbulence of magma flow.  相似文献   

Theoretical and experimental dynamic behaviour of a curved model bridge structure     

Kazuhiko Kawashima  Joseph Penzien 《地震工程与结构动力学》1979,7(2):129-145

Correlations between analytical and experimental seismic responses of a curved model bridge structure, which was constructed to have the same features as a typical full-scale high curved highway bridge structure, are presented. Dynamic behaviour and seismic response of the experimental bridge model are examined with particular emphasis on the discontinuous behaviour of expansion joints. Modelling of Coulomb type friction with slippages and impacting at the expansion joints is described. Correlations of displacement response of the bridge model carried out for three seismic excitations are presented. Parameter studies conducted to assist in the interpretation of correlation results are presented and the characteristics of the dynamic behaviour of the bridge model are discussed.  相似文献   

Evolution of a precipitating cloud and cloud droplets     

Takao Takeda 《Pure and Applied Geophysics》1975,113(1):891-907

The evolution of a precipitating convective cloud was studied by a time-dependent numerical model in which for the simplification of dynamical framework the domain under consideration was expressed by three regions: inner region of cloud, outer region of cloud and environmental region. Clouds are assumed to have no ice-phase. The size distribution of water drops is described using five size-groups. Two types of cloud droplets (case A and case B) were given at cloud base. There are more small cloud droplets in case B than in case A. The slower production of raindrops in case B results in the later formation of a downdraft and rainfall than in case A. In consequence rainfall efficiency is lower in case B. These differences of both cases had a tendency to be larger in a less unstable atmosphere.  相似文献   

UT variation of internal S_q currents and the oceanic effect during 1980 March 1–18     

Masahiko Takeda 《Geophysical Journal International》1985,80(3):649-659

Summary. UT variation of the internal part of S _q currents is examined using the geomagnetic data during 1980 March 1–18, and the effect of the ocean is found. The ratio of the internal currents to the external increases when the external current vortex comes above the Atlantic and Pacific Oceans, and the internal current vortex shifts to the oceans when the external vortex approaches the edge of the oceans. The existence of the ocean increases the total induced current by about 30 per cent and this amount is consistent with model calculations for S _q by previous workers.  相似文献   

Life Recovery of 1995 Kobe Earthquake Survivors in Nishinomiya City: A Total-Quality-Management-Based Assessment of Disadvantaged Populations     

Takeda  Joe  Tamura  Keiko  Tatsuki  Shigeo 《Natural Hazards》2003,29(3):567-585

The main objectives of this study were (1) to examine what has beenrecovered and what has not yet been recovered in Nishinomiya City five years after the GreatHanshin-Awaji Earthquake, and (2) to find current service needs for the earthquake survivors,especially for the disadvantaged populations. Disadvantaged populations are minorities in society, andtheir needs and opinions are often ignored and not reflected in the services or mitigation policy,despite the fact that they are the ones who are affected most by various hazards. At the same time, becauseof their unique characteristics and positions in society, their needs differ from the majorityof the society. Six hundred eighty-six opinion cards were collected in nine grassroots workshopsessions with various disadvantaged groups in Nishinomiya City, such as the physically challenged,the visually impaired, the elderly living in public housing, junior and senior high school students,mothers with small children, and those who lost their own homes because of the earthquake. Theseopinion cards were sorted out and analyzed by using a TQM(Total Quality Management)-basedassessment method. Since the TQM-based assessment method allows bottom-up integration ofopinions from each individual, it helps us identify unique needs of the disadvantaged groupsand reflect their opinions in mitigation plan and policies. The main findings of this study include (1)the city redevelopment cannot be achieved without integrating the viewpoints of thedisadvantaged; (2) the social support was a key resource for both mental health and community development;and (3) disaster experiences and adaptation produced civic mindedness among people in a community.  相似文献   

Deformation structures in shale bed indicate flow direction of overlying Miocene subaqueous pyroclastic flow     

Kazuhiko Kano  Shun Nakano  Koji Mimura 《Bulletin of Volcanology》1988,50(6):380-385

Thrusts, pinch-and-swell structures and undulations are present within a 2-m-thick layered shale bed of Miocene age that is overlain by a rhyolite subaqueous pyroclastic flow deposit 2–3 m thick. The deformation structures were caused by loading and lateral compression by the subaqueous pyroclastic flow, probably analogous to those observed in layered muds deformed by a sand mass advancing across them. Prominent thrusts strike east-west and dip south, and the crests of undulations strike east-west, indicating that the subaqeuous pyroclastic flow moved northward.  相似文献   

Effect of pressure on the crystal structure of perovskite-type MgSiO3     

Y. Kudoh  E. Ito  H. Takeda 《Physics and Chemistry of Minerals》1987,14(4):350-354

The crystal structure of perovskite-type MgSiO₃ has been studied up to 96 kbar, using a miniature diamondanvil pressure cell and by means of single-crystal four-circle diffractometry. The observed unit cell compression gives a bulk modulus of K _o=2.47 Mbar, assuming K′_o=4. The unit cell compression is controlled mainly by the tilting of SiO₆ octahedra. The effect of pressure is to change Mg polyhedron towards 8-fold coordination rather than 12-fold coordination. The polyhedral bulk moduli of SiO₆ and MgO₈ are 3.8 Mbar and 1.9 Mbar, respectively.  相似文献   

Earthquake response spectra taking account of number of response cycles     

Kazuhiko Kawashima  Koh Aizawa 《地震工程与结构动力学》1986,14(2):185-197

Proposed is a new definition of earthquake response spectra, which takes account of the number of response cycles N. The Nth largest amplitude of absolute acceleration response of a linear oscilator with natural period T and damping ratio h, which is subjected to ground motion at its base, is defined as S_A(T, h, N). By defining a reduction factor η(T, h, N) as S_A(T, h, N)/S_A(T, h, 1), characteristics of η(T, h, N) were investigated based on 394 components of strong motion records obtained in Japan. Two practical empirical formulae to assess the reduction factor η(T, h, N) are proposed.  相似文献   

Ambient air measurements of six bifunctional carbonyls in a suburban area     

Ricardo Ortiz  Hiroyuki Hagino  Kazuhiko Sekiguchi  Qingyue Wang  Kazuhiko Sakamoto   《Atmospheric Research》2006,82(3-4):709

Low-molecular-weight carbonyl compounds, generated by photochemical reactions in the atmosphere and found in the exhaust of motor vehicles, have recently come to the attention of researchers because some of them are suspected carcinogens or mutagens. Six bifunctional carbonyl compounds were detected and measured in a suburban site 30 km northwest of the Tokyo metropolitan area. Samples were taken on five sunny days between 2 August and 11 August 2003 with a low-volume denuder and three-filter tandem system using O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) as a sorbent. Bifunctional carbonyls were measured by gas chromatography–mass spectrometry after two derivatization processes with PFBHA and N,O-bis(trimethylsilyl)-trifluoroacetamide (BSTFA). The average total (gas plus particle) concentrations were 162.8 ng m^− 3 for pyruvic acid, 113.7 ng m^− 3 for methylglyoxal, 36.0 ng m^− 3 for glycolaldehyde and 58.6 ng m^− 3 for glyoxal.  相似文献