| Budget Amount *help |
¥12,000,000 (Direct Cost: ¥12,000,000)
Fiscal Year 2004: ¥4,400,000 (Direct Cost: ¥4,400,000)
Fiscal Year 2003: ¥7,600,000 (Direct Cost: ¥7,600,000)
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| Research Abstract |
Since the aluminum deck that had been developed using the Friction Stir Welding(FSW), consisted of closed sections, it was impossible to examine visually the back surface of the FSW-joints. In this research, an aluminum deck of open-closed sections was newly designed, where conducting FSW on the open sections made the visual inspection of the back surface of the FSW-joints possible.
The extrusions where overhangs were provided on both sides of the top flange of the closed section were designed. The ends of the overhangs of the extrusions were butted, and FSW was done there. The steel girders were fabricated at the limiting value of the web slenderness ratio when no horizontal stiffeners are provided. Three steel stud shear connectors were welded to the top flange of the steel girders in one row in the bridge-transverse direction. A form work was laid surrounding the studs to leave the supporting mortar between the top flange of the steel girders and the bottom flange of the aluminum ext
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rusion. The studs were inserted inside the extrusion through a rectangular cutting on the bottom flange. The non-shrinkable mortar was filled through the hole on the top flange of the extrusions. Statically loading tests of the aluminum deck laid on the steel girders were carried out.
The friction-type high-strength steel bolts were used for the on-site connections of the aluminum decks. To secure the friction on the surface of the aluminum members, the tensile tests of the specimens where the roughness was controlled were carried out, and the relation between the roughness of the aluminum members and the coefficient of friction was given. The on-site connections were fabricated for both of the sides and the ends of the aluminum decks, to confirm the ultimate strength and fatigue strength.
When connecting aluminum decks to steel girders, since the coefficients of thermal expansion are twice as different between aluminum and steel, there may be a possibility that the stress which can not be ignored is produced in the aluminum decks according to the temperature change. Therefore, the degree of the composite action between the aluminum decks and the steel girders must be clarified. For this, the composite girders of the aluminum decks and the steel girders were fabricated. Less
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