Development of Aluminum Decks Using Friction Stir Welding

由于使用搅拌摩擦焊(FSW)开发的铝甲板由封闭的部分组成，因此不可能直观地检查FSW接头的背面。在本研究中，设计了一种新的铝制开闭式截面甲板，在开口截面上进行搅拌摩擦焊，可以直观地检测搅拌摩擦焊接接头的后表面，并设计了在封闭截面顶部凸缘两侧设置悬臂的挤压件。挤压的突出端是对接的，并在那里进行FSW。在没有设置水平加劲肋的情况下，按腹板长细比的限值制造钢梁。三个钢柱剪力连接件沿桥梁横向一排焊接在钢梁的上翼缘上。在立柱周围铺设了模板，以在钢梁的顶部翼缘和铝制Ext…的底部翼缘之间留下支撑砂浆更多的生锈。螺柱通过底部凸缘上的矩形切割插入挤压内部。非收缩砂浆通过挤压件顶部凸缘上的孔填充。对钢梁上铺设的铝桥面进行了静载试验，铝桥面的现场连接采用了摩擦型高强度钢螺栓。为了保证铝构件表面的摩擦，对控制粗糙度的试件进行了拉伸试验，给出了铝构件表面粗糙度与摩擦系数之间的关系。在铝桥面与钢梁连接时，由于铝桥面的热膨胀系数与钢材的热膨胀系数相差一倍，根据温度的变化，有可能在铝桥面产生不可忽略的应力。因此，必须明确铝桥面与钢梁之间的组合作用程度。为此，制作了铝桥面与钢梁的组合梁。较少

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 … More 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