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Shunichi NAKAMURA, Masayuki OKIMOTO, Tomonori TOMINAGA, Tetsuo TAKEDA, ...
1998 Volume 5 Issue 17 Pages
1-11
Published: March 30, 1998
Released on J-STAGE: June 28, 2010
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A new type cable-stayed bridge has been invented: the girders are steel pipes, filled with concrete whose volume depends on the span position, and composite with concrete slab. The static and dynamic characteristic has been studied for a model bridge with main-span of 900m. It is found that a new system has a good balance of deflection and sectional forces, and the composite pipe girders can be designed by RC method, which has been verified by the bending tests. Dynamic study has shown that a new system has the same strength against wind forces as existing long span cable-stayed bridges. The new system has also been proved feasible on detail design and erection procedures.
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(Analysis Using Single-Degree-of-Freedom Systems)
Koji OGAWA, Kazuo INOUE, Satoko ONO
1998 Volume 5 Issue 17 Pages
13-28
Published: March 30, 1998
Released on J-STAGE: June 28, 2010
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This paper deals with steel frames in which hysteretic dampers are incorporated and examines the strength required for the main frames consisting of columns and beams to stay within elastic region under strong ground motions. The energy dissipation provided by hysteretic dampers reduces the required strength. On the other hand, the total input energy is affected by plastic deformation, since the increase of plastic deformation means elongation of the apparent natural period and the total input energy depends on the apparent natural period. The benefit of hysteretic damping and the effect of plastic deformation on the input energy are evaluated individually based on the energy balance concept. An analytical expression of the required strength is formulated considering these two effects.
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(Base Shear Coefficient for Multi-Degree-of-Freedom Systems)
Koji OGAWA, Kazuo INOUE, Satoko ONO
1998 Volume 5 Issue 17 Pages
29-44
Published: March 30, 1998
Released on J-STAGE: June 28, 2010
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In previous paper we examined the strength required for a single-degree-of-freedom system to maintain columns and beams in elastic region under earthquake loading . In this paper the equivalent singledegree-of-freedom system is discussed whose responses against earthquakes are approximately equal to those of a multi-degree-of freedom system and the ratio of the maximum base shear force of a multi-degree-of freedom system relative to the maximum shear force of the equivalent single-degree-of-freedom system is quantified. The damage concentration in a weak story caused by the inevitable fluctuations of story yield strengths is also considered. A formula is proposed to evaluate the required base shear coefficient of a multidegree-of freedom system.
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Teiji OTA, Isao SHIMIZU, Nobutaka ISHIKAWA
1998 Volume 5 Issue 17 Pages
45-55
Published: March 30, 1998
Released on J-STAGE: June 28, 2010
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This paper examines if the steel-concrete composite structure can be applied to the rock-shed structure or not from the view points of four impact tests. Four kinds of experimental studies, i.e., 1) impact tests of steel-concrete composite beams filled with rigid urethane, 2) high speed loading tests of open san witch composite beams, 3) high speed punching shear tests o steel-concrete composite slabs and 4) high speed shear loading tests of stud bolts were carried out. From these tests, it is found that the steel-concrete composite structures have both high strength and deformability under impact and high speed loadings. Therefore, it is recognized that the steel-concrete composite structure will be useful for the rockshed under severe rock-fall condition.
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Kenji UMEZU, Manabu FUJITA, Hideo ARAI, Tamon VEDA, Hirokazu FUSHITA
1998 Volume 5 Issue 17 Pages
57-66
Published: March 30, 1998
Released on J-STAGE: June 28, 2010
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To reduce the size of deviators in the external tendon systems, the bending radius of the external tendon at the deviators is normally designed to be smaller than that in the internal tendon systems. This practice raises concern about the fretting fatigue of tendons. In this study fretting test on S15.2 strands used as the external tendons in PC bridges were carried out. Rust due to fretting corrosion was observed at the starting point of the fatigue fracture on the strands surface. An S - N diagram for the strand in the deviator was derived from the fatigue tests, and it was confirmed that the fatigue life is shortened by fretting between strands.
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Akihiko KAWANO, Chiaki MATSUI, Koji ARIKADO, Rumi SHIMIZU
1998 Volume 5 Issue 17 Pages
67-74
Published: March 30, 1998
Released on J-STAGE: June 28, 2010
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In this paper, the requirements of the column-overdesign factors for forming the weak-beam plastic mechanisms are investigated in 3, 6 and 12 story steel frame models subjected to strong ground accelerations. In order to take the account of randomness in the yield strength of each member, the Monte-Carlo method is adopted. A slight plastification in columns could be allowed in a steel frame because of a rather stable hysteresis in the interstory shear-drift relation. Therefore, the plastic mechanism could be judged as the weak-beam type for the frame, in which the average of accumulated plastic rotations in all columns never exceeded a specified tolerance. The probability of the mechanism formation is shown corresponding with the column-overdesign factor.
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Masahiro SAKANO, Masaki TSUJIO, Keiji FUJIWARA, Ichizo MIKAMI
1998 Volume 5 Issue 17 Pages
75-84
Published: March 30, 1998
Released on J-STAGE: June 28, 2010
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We discussed the validity of cut-off limits for variable amplitude stresses in fatigue design curve for steel railway bridge members through fatigue crack propagation analysis. As a result, the linear cumulative damage rule with cut-off limits regulated for electric-train-type variable amplitude stresses was found to give about 50% underestimation for fatigue damage in some cases.
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You Chul Kim, Jeong Ung Park, Kohsuke HORIKAWA
1998 Volume 5 Issue 17 Pages
85-91
Published: March 30, 1998
Released on J-STAGE: June 28, 2010
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Residual stress generated in manufacturing did not influence out-of-planedeformation, residual stress and plastic strain produced by welding. The shape and magnitude ofdeflection generated in manufacturing considerably influenced out-of-plane deformation produced bywelding. However, they did not influence residual stress and plastic strain. If the total heat inputwas same, the welding speed did not influence out-of-plane deformation, residual stress and plasticstrain produced by welding. The heat input which is decided for the plate thickness did not influenceout-of-plane deformation, residual stress and plastic strain produced by welding.Keywords:
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Akihiko KAWANO, Chiaki MATSUI, Nozomu MURAI
1998 Volume 5 Issue 17 Pages
93-104
Published: March 30, 1998
Released on J-STAGE: June 28, 2010
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This paper presents load-deformation relation models for connections of H-shaped steel beams to concrete filled rectangular tubular columns (CFRT columns) in moment resistant frames. Although the column is usually stiffened by a steel plate diaphragm at the connection, a reduction of diaphragm rigidity, which is caused by a concrete casting hole in the diaphragm, leads to a fairly large local deformation at the beam flange joint. A simple model of the relation of beam flange load and local deformation is proposed for typical connection types of the external diaphragm, the inner diaphragm, and the inner diaphragm with extended flanges. The model is compared with an experimental data base and a FEM numerical data base.
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Norio TOKUNAGA, Takashi NISHIMURA, Yoshiya TANIGUCHI
1998 Volume 5 Issue 17 Pages
105-114
Published: March 30, 1998
Released on J-STAGE: June 28, 2010
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This paper presents the vibration characteristics of a bridge with a wide clear width on the vibration generated by traffic loading. On the bridge with the wide clear width, it is apt to produce torsional vibration. Natural frequencies of bending vibration mode are similar in each girder, however their phases are not equal. Therefore, the rest institution vibrates in bridge axial direction and at right angle to its direction. By the results of this study, the effectiveness of tuned mass damper for buildings is about -5 -11dB on harmonic vibration, and -3-5dB on random waves . However a t the bu i 1 d i ng on the bridge with the wide clear width, the reduction o f the vibration level with a tuned mass daluper is no more than -1-3dB.
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Akihiko KAWANO, Chiaki MATSUI, Nozomu MURAI
1998 Volume 5 Issue 17 Pages
115-127
Published: March 30, 1998
Released on J-STAGE: June 28, 2010
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The purpose of this paper is to propose an analytical model for the elastic plastic analysis of moment-resistant frames consisting of concrete-filled rectangular tubular columns (CFRT columns), H-shaped steel beams, and typical connections using steel plate diaphragms. A hole in the diaphragm of such a connection is inevitable for concrete casting, and might result a low diaphragm rigidity and a plastic local deformation around the beam flange joint. The eight cruciform subassemblages were tested in order to develop the analytical frame model in which the local deformations at connections were taken into account. The model accuracy is demonstrated in comparison with the experimental data base including the other experimental reports. Being based on a parametric study by using the model, the amount of the local deformation at the connection are discussed on the bases of the relative strengths of the connections, joint panels, beams and columns.
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Teruyasu KAMBA
1998 Volume 5 Issue 17 Pages
129-139
Published: March 30, 1998
Released on J-STAGE: June 28, 2010
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The paper describes a numerical study on CHS (Circular Hollow Section) steel column semi rigid connections. Connections here is that gusset plates (flange plates) or H-beams are welded directly to columns. The numerical work was carried out by FEA with 118 model of the specimens subjected to tension or compression load through flange plates and 114 model of the subassemblage specimens under symmetrical loading. It was involved 90 numerical analyses of Finite Element models with parameters of the diameter to thickness ratio (D/t) and the flange width to diameter ratio (Bf/D). Evaluations of the numerical results showed as follows: (1) the affective parameters on the behaviour of the connections is the D/t and the Bf/D ratio, (2) the compression strength is less than the tension one in case of D/t >27, and it is not less than the tension strength in case of D/t <22, (3) the empirical formulae obtained by regression analysis estimate well the elastic-plastic behaviour of the connections.
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Ben KATO
1998 Volume 5 Issue 17 Pages
141-147
Published: March 30, 1998
Released on J-STAGE: June 28, 2010
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Premature fractures of beam flange at the vicinity of beam-to-column moment resisting connections were widely observed in the 1995 Hyogoken Nanbu earthquake. In this paper, the causes of the fracture are assessed. Based on this assessment, an improved beam-to-column connection detail is proposed. The formula to predict the plastic rotation capacity of this im proved beam system is presented.
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