1.

論文(リポジトリ)

論文(リポジトリ)
有住, 康則 ; 浜田, 純夫 ; 大城, 武 ; Arizumi, Yasunori ; Hamada, Sumio ; Oshiro, Takeshi
出版情報: 琉球大学工学部紀要.  pp.43-57,  1982-03.  琉球大学工学部
URL: http://hdl.handle.net/20.500.12000/14670
概要: In resent years, horizontally curved steel - concrete composite girder bridges have been employed as one of highway brid ges. The behavior of curved composite I - girders has been studied by several researchers. However, the design of shear connectors for curved composite box girders has not been prescribed in the specification. This paper presents a finite strip analysis for horizontally curved composite girder bridges with incomplete interaction. This is applied to the analysis of curved one and two box girders and curved plate girders. The numerical results are compared with the test and computational values based on the finite element and finite strip method by other researchers, and found to be in good agreement. The behavior of curved composite box girder bridges with incomplete interaction is discussed based on the analytical results by the proposed method.
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2.

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大城, 武 ; 浜田, 純夫 ; 成底, 弘敏 ; 有住, 康則 ; Oshiro, Takeshi ; Hamada, Sumio ; Narisoko, Hirotoshi ; Arizumi, Yasunori
出版情報: 琉球大学工学部紀要.  pp.57-74,  1981-09.  琉球大学工学部
URL: http://hdl.handle.net/20.500.12000/14688
概要: Most of RC bridges in Okinawa Prefecture have been constructed near the shore and deterioration of concrete due to rust of reinforcing bars becomes serious. Several investigations such as surface observations, truck loading tests and bending failure tests of main beams have been performed. These are mainly for static and fatigue behavior of a beam becomes important for the consideration of durability. Generally, fatigue strength of materials such as concrete and reinforcing bars is the major factor in determination of strength of a beam and fatigue behavior of the beam has not been seriously studied. However, it is considered as important since significant deterioration has been observed recently. Two beams tested here were cut of a deteriorated bridge and the appearance showed spalls of concrete on surface. Apparent losses in cross section of bars and bond stress were observed. This paper presents the results of fatigue test subjected to repeated loads where increasing rates of deflection, strain of bars and crack width and effectiveness of bond stress were carefully investigated. The immediate conclusions are as follows: (1) The significant reduction of bending rigidity and increase of crack width were not observed after repeated load, but residual deflection, strain and crack width were not negligible. (2) Sudden failure of test beams occured due to brittle failure of a reinforcing bar, which could be explained as the overstressing of a particular bar as result of loss in bond stress at neighboring bars.
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3.

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浜田, 純夫 ; 有住, 康則 ; 名護, 健一 ; Hamada, Sumio ; Arizumi, Yasunori ; Nago, Kenichi
出版情報: 琉球大学工学部紀要.  pp.31-39,  1981-03.  琉球大学工学部
URL: http://hdl.handle.net/20.500.12000/14689
概要: Partial composite beams have been practiced in the United States and Canada, but the partial composite beams with partly complete interaction in the negative bending region are not included in the highway bridge specifications. However, from theoretical analysis, the stiffness of partial composite beams with partly complete interaction is greater than that of partial composite beams without shear connectors in the negative bending region and reinforcement strains do not significantly increase comparing with the increase of the bending stiffness. Three composite beams are tested in order to provide additional information on the bending behavior of the partial composite beams. The test beams varied in terms of shear connector spacing. Special attentions are paid to the bending stiffness, efficiency of reinforcing bars, crack pattern, maximum crack width, residual crack width, slip and deflection. High cycle loading is applied on the basis of the design load. The following conclusions can be drawn from the present study; (1) Relationships between load and deflection become close to the theoretical ones gradually as increase of the number of loads. (2) The reinforcement in the concrete slab is effective to bending, however the residual reinforcement stresses increase as increase of the number of loads. (3) The residual crack width and maximum crack width at the design load do not increase due to increase of the number of crack. (4) The relationship between maximum crack width and reinforcement stress is approximately linear. (5) Little difference of ultimate strength arises among three composite beams.
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4.

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有住, 康則 ; 筑瀬, 明弘 ; 浜田, 純夫 ; 梶田, 建夫 ; Arizumi, Yasunori ; Chikuse, Akihiro ; Hamada, Sumio ; Kajita, Tateo
出版情報: 琉球大学工学部.  pp.69-88,  1980-09.  琉球大学工学部
URL: http://hdl.handle.net/20.500.12000/14690
概要: Recently the load factor method has been taking the place of the allowable stress method for composite members in the Un ited States and European countries. It is the most important in the load factor design method to assure the mechanical behavior such as ultimate capacity of the structure. Ultimate strength is based on the properties of steel, concrete and shear connectors. In the present study some discussions on ultimate states are provided for composite beams with incomplete interaction applying elastic-plastic analysis. Some studies on the elastic analysis for incomplete composite beams have been presented in the bulletin by authors, and this is developed to inelastic analysis based on bilinear elasto-plastic properties of concrete, steel and shear connectors by means of the finite element method. An iterative initial strain method is employed in the present analytical procedure, where inelastic strains and deformations of materials are evaluated to the equivalent loads. This is also applied to analysis of cracked reinforced concrete beams. The main results of the analysis are as follows; (1) There is not much difference in the mechanical behavior of composite beams with shear connectors between spaced equally and spaced proportinally to horizontal shear. (2) Composite beams with partial interaction have an advantage of stress reduction on longitudinal reinforcing bars in negative moment regions, where it may be near the point of counterflection. This tendency becomes more apparent along with extent of the plastic range.
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5.

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浜田, 純夫 ; 有住, 康則 ; 与那嶺, 隆 ; 宮良, 信秀 ; Hamada, Sumio ; Arizumi, Yasunori ; Yonamine, Takashi ; Miyara, Nobuhide
出版情報: 琉球大学理工学部紀要. 工学篇 — Bulletin of Science & Engineering Division, University of the Ryukyus. Engineering.  pp.49-60,  1979-03-01.  琉球大学理工学部 — Science and Engineering Division, University of the Ryukyus
URL: http://hdl.handle.net/20.500.12000/27614
概要: Studies on the behavior of composite beams under negative bending have been conducted experimentally and theoretically a nd discussed in the previous bulletins. The previous experimental study was limited within static loading, and the present study is to investigate the behavior of composite beams under repeated negative bending. Test beams consists of composite beams with studs spaced normarly and with studs spaced at the beam ends. Call the latter beam as a "partial composite beam" herein. Special attentions are paid to the bending stiffness, efficiency of slab reinforcing bars, maximum crack width, crack pattern, residual stress in the reinforcement, residual crack width and ultimate strength. High cycle loading and low cycle loading are applied on the basis of the design load and of the ultimate strength based on the nominal yield stress, respectively. Static test is also conducted after the fatigue test. Following conclusions are obtained from the present study. (1) Relationships between load and deflection become close to the theoretical ones gradually as increasing number of loading. (2) Slab reinforcement is effective to bending, however reisdual stress in the reinforcement increases as the increase of number of loading. (3) Apparent difference of maximum crack width does not occur between complete and partial composite beams. The relationship between maximum crack width and stress in slab reinforcement is expressed as linear. (4) No difference of ultimate strength is shown between complete and partial composite beams after fatigue test.
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6.

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浜田, 純夫 ; 有住, 康則 ; Hamada, Sumio ; Arizumi, Yasunori
出版情報: 琉球大学理工学部紀要. 工学篇 — Bulletin of Science & Engineering Division, University of the Ryukyus. Engineering.  pp.43-51,  1978-09-01.  琉球大学理工学部 — Science and Engineering Division, University of the Ryukyus
URL: http://hdl.handle.net/20.500.12000/27455
概要: Composite beams with no shear connectors in the negative moment region have been practiced in the United Stares, althoug they are not specified in the specification of highway bridges in Japan. A few studies on the composite beams with no shear connectors, called partial composite beams herein, have been conducted by Y. Maeda, the authers, and the athers. Y. Maeda tested several continuous composite beams with patial interaction in the negative bending region and discussed about the shear force acting on shear connectors at the ends of the composite region, and the stress of reinforcing bars in the concrete slab in a negative moment region. The authers conducted several tests of isolated composite beams under negative bending. The test beams consist of complete composite beams and partial composite beams where the slab and steel beam are connected at the ends by means of shear connectors. The test result shows that the reinforcement in the slab of the partial composite beams are effective, and that the beams are more flexible than the complete composite beams. The present paper gives dicussions on the stress produced in the slab and the stiffness of partial composite beams from the theoretical analysis. The results show the following conclusions. 1). The stress in the concrete slab for the partial composite beam is a half of that for complete composite beams. 2). The lower flange stress does not increase so much comparing with the decrease of the slab stress. 3). Deflection and stress ratios of the partial composite beam to the complete composite beam depend mainly on the effective slab area. 4). Experimental results conducted by the authers well coinside with the theoretical results discussed herein.
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7.

論文(リポジトリ)

論文(リポジトリ)
大城, 武 ; 浜田, 純夫 ; 多和田, 伸 ; 加藤, 準一 ; Oshiro, Takeshi ; Hamada, Sumio ; Tawata, Shin ; Kato, Junichi
出版情報: 琉球大学理工学部紀要. 工学篇 — Bulletin of Science & Engineering Division, University of the Ryukyus. Engineering.  pp.57-69,  1978-03-01.  琉球大学理工学部 — Science and Engineering Division, University of the Ryukyus
URL: http://hdl.handle.net/20.500.12000/27019
概要: Practical applications of the box culvert have been common in many fields, since precast concrete products reduce compli cated procedures of situcast concrete at field. The main characteristics of precast product are well controlled processes and guaranteed guality, which are reguired for R.C structures to keep high durability especially in Okinawa prefecture since many damages of R.C structures due to salt are reported recently. The other characteristics is to reduce the weight of box culvert which is performed by introduction of the partially prestressing technigue, i,e., only top and bottom slabs are prestressed by use of unbonded P.C,tendons. Many tests have been conducted by user's reguests, where only crack and failure loads are interested. Therefore, close investigations on structural behaviors up to failure are observed in a few cases. This paper places emphasis on the behaviors by making use of theoretical and test results where deflections, strains, crack loads, ultimate loads and crack patterns are described. The theoretical and test results give the following conclusions: (1) Theoretical values of deflection are quite close to the test results and Branson's equation after crack initiation well coincides with the test values. According to the values of deflection, the reaction with sand cushion could be assumed as uniform distribution. However, strain diaqrams do not yield the same conclusion and it requires more research on the distribution of reaction. (2) Measured strains become much smaller than the theoretical ones, and. consequently, the crack loads become 1.64 times the design load for two box culverts, which indicats sufficient resistance to repeated load. (3) Ultimate strength shows 4 times the design load and it will be concluded that the box culverts are safe enough in practical uses asthe under ground structure.
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8.

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論文(リポジトリ)
浜田, 純夫 ; 佐久川, 政健 ; 渡慶次, 一彦 ; Hamada, Sumio ; Sakugawa, Seiken ; Tokeshi, Kazuhiko
出版情報: 琉球大学理工学部紀要. 工学篇 — Bulletin of Science & Engineering Division, University of the Ryukyus. Engineering.  pp.113-124,  1977-09-30.  琉球大学理工学部 — Science and Engineering Division, University of the Ryukyus
URL: http://hdl.handle.net/20.500.12000/26916
概要: Composite girders are used extensively as highway bridges and the most of them are simple span girders. Although continu ous composite girders are more economical, give better driving conditions, and have greater capacity than simple span girders, they have not been used much because of complicate construction where prestressing is involved in negative moment regions. The alternative method results in continuous composite girders with normal reinforcement in concrete slab in the region of negative bending. Composite girders with no shear connectors in the negative moment region have been specified in AASHO Specification. Such composite girders are commonly practiced in the United States, although the area of reinforcing bars in the slab is neglected in the analysis. The present paper describes the test results of composite beams with shear connectors at the beam ends, which are subjected to negative bending. The test results show that the reinforcement is effective to tension stress produced in the concrete slab and that the ultimate moment of the beams tested are higher the theoretical ultimate moment. However, composite beams with shear connectors at the beam ends are more flexible than normal composite beams.
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9.

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大城, 武 ; 浜田, 純夫 ; 上間, 源蔵 ; 上山, 秋雄 ; Oshiro, Takeshi ; Hamada, Sumio ; Uema, Gengo ; Ueyama, Akio
出版情報: 琉球大学理工学部紀要. 工学篇 — Bulletin of Science & Engineering Division, University of the Ryukyus. Engineering.  pp.125-137,  1977-09-30.  琉球大学理工学部 — Science and Engineering Division, University of the Ryukyus
URL: http://hdl.handle.net/20.500.12000/26917
概要: Deterioration of reinforced concrete bridges in use has become significant recently, and it is required to have full inv estigations on durability and serviceability of those bridges. Especially, these problems are urgent in Okinawa Prefecture, since most bridges are constructed along coastal area and reinforced bars are easily rusted under the influence of salt water. Therefore, the apparances show the worst condition, where cracks and spalls are observed due to expansion of reinforcing bars. Durability of those bridges has been estimated by external appearance only since there exist not enough materials. However, these estimations lack completely rational bases and it has been reguired to conduct some experimental analysis based on durability and material strength. New reserch program on durability of old reinforced concrete bridges is planned to investigate the problems mentioned above at Civil Engineering Reserch Center, Ministry of Construction, G.O.J. and this experimental reserch belongs to a part of the program. Yaka bridge was selected for this program, which was constructed on Rout 329 by U.S. Army in 1952. The apperance shows the typical mode of deterioration of R.C. bridges where rust on reinforcing bars results in cracks on covering concrete. Two main beams were cut out of the bridge during the reconstruction. Static bending test was performed on the test beams. The purpose of this test is to investigate general behavior during the bending test up to failure, and deflections and stresses are measured to compare with conventional reinforced concrete theory. It is concluded that the test beams behave elastically up to the design load and that the ultimate strength obtained from the test consist with the conventional theory, though one expected much reduction in capability from the appearance. There exist a few of this kind of tests and the results of this test will be useful for further investigation of deteriorated R.C. bridges.
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10.

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Hamada, Sumio ; Longworth, Jack ; 浜田, 純夫
出版情報: 琉球大学理工学部紀要. 工学篇 — Bulletin of Science & Engineering Division, University of the Ryukyus. Engineering.  pp.79-90,  1976-09-28.  琉球大学理工学部 — Science and Engineering Division, University of the Ryukyus
URL: http://hdl.handle.net/20.500.12000/26714
概要: Present design specifications for composite beams are based to a large extent on elastic theory. Elastic design is not e ntiely routine in the case of continuous beams, because the beam stiffness is different in positive and negatiue moment regions. An ultimate design approach elimnates this complication. The present investigation was planned with particuiar reference to the effect of longitudinal slab reinforcement on ultimate strength, failure modes and general behavior. Three two-span beams were tested under concentrated loads applied at the midsqan. From the test results main conclusions are; (1) The test beams exceeded the theoretical ultimate load based on simple plastic theory. (2) Principal failure modes in continous composite beams are crushing of concrete in positive moment regions and local flamge buckling in negative moment regions. The primary failure is affected by the amount of longitudinal slab reinforcement.
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