活载下悬索桥主缆变形特性

分别研究了悬索桥塔顶位移、主缆的弹性伸长及不平衡均布活载作用下的主缆的变形特性.研究了塔顶位移及主缆伸长与主缆垂度变化的关系,垂跨比越小,主缆垂度改变量越大,并给出了相应的解析式.通过能量守恒与主缆中力的平衡关系研究了使主缆产生最大竖向位移的均布荷载加载形式.研究表明,在假定主缆不可伸长的情况下,最不利加载并非为半跨加载,不平衡活载引起的最大挠度仅与恒活载之比及主缆垂度有关,并给出了相应的计算公式.根据实际工程建立有限元模型对上述公式进行了验证,结果与理论值符合良好.

Deformation Characteristics of Main Cable in Suspension Bridge Caused by Live Load

Deformation characteristics of main cable in suspension bridges was studied under the effect of displacement of tower, elastic elongation and unbalanced load. The relationship among the change of cable sag, the elongation of the cable and the displacement of tower top was studied. The smaller the sag ratio was, the larger the sag changed. The most unfavorable loading mode was researched by means of energy method and equilibrium condition of force. Results show if there was no elongation, the maximum deflection caused by unbalanced distributed load was relevant to the ratio of live load to dead load and the sag of cable. Analytic formulas were given and verified by a finite element model. The results agreed well with the theoretical value.