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混合强度U形肋加劲钢板是由U形肋和被加劲板采用不同强度组合而成的,用作桥面板,可充分发挥钢材的使用效率、降低工程造价。按不同结构尺寸和不同强度组合的U形肋与被加劲板,设计制作了9个混合强度U形肋加劲钢板试件。在轴向压力作用下,试验得到了这些U形肋加劲钢板试件的破坏模式、稳定承载力以及荷载位移曲线。将试验试件截面的低强钢部分等效为具有初始压应力的等强钢构件,并考虑试件焊接残余应力分布,分析了该加劲钢板失稳破坏机理。试验结果表明,试件整体失稳有被加劲板受弯失稳和U形肋受弯失稳两种,局部屈曲或材料屈服可发生在U形肋的翼缘、U形肋的腹板和被加劲的钢板中。试件两端的转动装置是否被约束对试验结果也有较大影响,有约束情况下,在试件端部附近的U形肋会发生局部屈曲破坏;无约束的情况下,在试件中部区域的加劲肋会发生局部屈曲破坏或试件整体发生弯曲破坏。对于发生整体失稳破坏的试件,结构具有较大的延性,平均应力峰值变化较大;而发生局部失稳破坏的试件,结构破坏具有明显的脆性,其平均应力峰值基本不变。
Mixed strength U-shaped rib stiffened steel plate is made of U-shaped ribs and stiffened plates with different strength combinations, used as a bridge deck, which can give full play to the use of steel efficiency and reduce project costs. According to the U-shaped ribs and the stiffened plates which are combined with different structural sizes and different intensities, nine composite U-shaped ribbed steel specimens were designed and manufactured. Under the action of axial pressure, the failure mode, the stable bearing capacity and the load displacement curve of these U-shaped rib stiffened steel specimens were obtained. The low-strength steel part of the test specimen section is equivalent to the isotropic steel member with initial compressive stress, and considering the distribution of welding residual stress, the failure mechanism of the stiffened steel plate is analyzed. The experimental results show that the buckling of the stiffened plate and the buckling of the U-shaped rib are two kinds of instability of the specimen. The local buckling or material yielding can occur in the flange of the U-shaped rib, the web of U-shaped rib and Be stiffened in the steel. Whether the rotating device at both ends of the specimen is restrained also has a great influence on the test results. If there is a constraint, the local buckling damage will occur to the U-shaped rib near the end of the specimen. In the unrestrained case, Local buckling of the stiffener will occur or bending damage may occur to the entire specimen. For the specimen with global instability failure, the structure has larger ductility and the average peak stress changes greatly. However, the specimen with local instability failure has obvious brittleness and the average stress peak is basically unchanged.