直线配索预应力I字简支钢梁静力性能参数分析

Static Parameters Analysis for Prestressed Steel Beam with Linear Cable

采用有限元数值的方法,建立了预应力I字钢梁配置直线型拉索的单跨简支计算模型。通过对预应力钢梁与普通钢梁位移、应力的比较来反映预应力的效用,探讨了张力系数、梁高跨比、索偏心距跨度比、梁索刚度比、梁上下翼缘面积比等设计参数对结构静力性能的影响。分析表明,配置直线型拉索的预应力钢梁在预应力合理区间内比相同工作条件下的普通钢梁控制应力减小50%,变形趋向于零。各设计参数应统筹考虑,张力系数对结构的应力比、位移比有较大的影响。在常规预应力钢梁设计中,梁索刚度比对计算结果影响不大。建议张力系数取0～2.5;索偏心距跨度比取0.03～0.06;梁上下翼缘面积比取0.1～1。

Applying finite element numerical method, a calculated model is established which is a single span beam with simple support using a linear prestressed cable. Comparing the displacement and stress of prestressed beam to that of the usual beam, the effectiveness of prestress is shown. The design parameters such as tension coefficient, the ratio of beam height and span, the ratio of cable eccentric distance and span, the ratio of beam and cable rigidity, the ratio of beam top and bottom flange area, ete, which affect static performance of structure, are discussed. The results show that the maximum stress reduces 50% and the displacement diminishes to near zero by steel beam prestressed with linear cable. Design parameters should be considered as a whole. The influence of tension coefficient on stress and displacement is sharp, while the ratio of beam and cable rigidity sounds light when designing common prestressed steel beam. It is suggested that the tension coefficient should take 0 - 2.5, the ratio of cable eccentric distance and span should take 0.03 - 0.06, and the ratio of beam top and bottom flange area should take 0.1 - 1.