混合强度U形肋加劲钢板受压稳定试验研究

Experimental study on compression stability of hybrid steel plate stiffened with U-ribs

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。

Plate stiffened with U-fibs of hybrid steel types is designed to adopt different strength steel materials for steel plate and the stiffening U-ribs according to their different forces, which may make full use of the materials and reduce the project cost. Nine specimens of plates stiffened with U-ribs of hybrid steel types were designed and manufactured, taking the structure size and material strength of the steel plate and the stiffening U-ribs as the design variables. Experiments of the specimens under axial loads were carried out. The failure mode, stability bearing capacity and the load-displacement relationship of the hybrid steel U-rib stiffened plate were investigated. The stability mechanism of plate stiffened with U-ribs of hybrid steel types under axial load was investigated, in which the members with low strength is equivalent to members with high strength by adding initial stress, and the distribution of the weld residual stress is also considered. Test results show that there are two kinds of failure modes, i.e.,buckling as a whole and local buckling or strength yielding. For the failure of buckling as a whole, the deflection direction may be toward the plate or the U-rib, while the local buckling or strength yielding may occur in the flange, web of the U-rib or the stiffened plate. Whether the rotation of the two ends of the specimen is restrained or not has a great influence on the test results. When the rotation is restrained, the U-rib near the end of the specimen will locally buckle. If the rotation is not restrained, the U-rib in the middle height of specimen will locally buckle or the specimen as a whole will fail due to bending. For the specimen buckling as a whole, the specimen exhibits a good ductility and the average peak stress will change quite a lot among various specimens; for the specimens that fail by local buckling or strength yielding, behave brittle and the average peak stresses are almost the same for all specimens.