大跨越钢管塔内外法兰节点偏压承载力特性试验研究

EXPERIMENTAL RESEARCH ON BEARING CAPACITY CHARACTERISTICS OF INNER-OUTER DOUBLE LAYERED FLANGE OF LONG-SPAN STEEL PIPE TOWER UNDER ECCENTRIC COMPRESSION

传统刚性法兰仅在钢管外侧设置一圈连接螺栓,难以满足高度高、荷载大的大跨越钢管塔连接承载力要求。为此,提出一种新型内外双圈法兰节点,它克服了传统刚性法兰存在的不足。以某大跨越钢管塔为背景,设计了与内外法兰原型节点相对应的法兰缩尺模型,模拟实际偏压受力工况开展偏压荷载下内外法兰承载力特性的试验研究;测试分析主管及螺栓应变随荷载变化的情况,研究内外法兰截面的中和轴、旋转轴位置及内外螺栓内力分布规律。大偏压荷载作用下法兰板间发生张开,螺栓发生颈缩破坏,小偏压荷载下钢管发生局部失稳破坏。最后,提出偏压荷载作用下内外法兰设计时,计算连接螺栓拉力可以取旋转轴位置为距离管中心0.6R(R为主管半径)。

Traditional rigid flange with bolts connection only outside pipe could not satisfy with the requirements of bearing capacity for long-span transmission line tower with larger height and loads,and a new-type of inner-outer double layered flange was proposed to overcome the deficiency of traditional flange. Taking a long-span transmission tower as an example,the scale model of inner-outer double layered flange corresponding to actual joint was designed,the loading tests to simulate the eccentric compression was carried out. The strains of main pipe and connecting bolts and these changes were measured,and the positions of neutral axis and rotational axis on the flange surface and the internal force distribution of bolts were investigated. The flange plates would open and bolts would be necking under large eccentric compression,and local buckle on main steel pipe would occur for small eccentric compression. Lastly,the position of rotational axis could be taken as 0. 6 R（R is the radius of the steel pipe） from the tube center to calculate the internal forces of connecting bolts under the eccentric compression during the design of inner-outer double layered flange.