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論文（リポジトリ） |
論文（リポジトリ）
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浜田, 純夫 ; 有住, 康則 ; 名護, 健一 ; Hamada, Sumio ; Arizumi, Yasunori ; Nago, Kenichi
概要:
Partial composite beams have been practiced in the United States and Canada, but the partial composite beams with partly
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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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| 2.
論文（リポジトリ） |
論文（リポジトリ）
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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
概要:
Recently the load factor method has been taking the place of the allowable stress method for composite members in the Un
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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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