本文以一实际长输管道悬索桥跨越工程为原型,制作了缩尺比例为1:8的试验模型,对试验模型的模态、抗震性能进行了白噪声和不同强度的El Centro波输入下的试验研究以及有限元分析。试验结果表明:试验模型的自振频率随地震强度的增加而降低,最大降低20%;试验模型的最大地震反应为塔架顶部的纵向振动,加速度达1.75g,折合原型为1.62g,动力放大系数为5.47。管道的地震反应以横向振动为主,最大加速度达1.21g,折合原型结构为1.12g,动力放大系数为2.63。试验过程中,输入的最大横向和竖向地震反应加速度折合原型均超过0.4g,但模型构件未发生破损,结构体系保持稳定,表明悬索跨越结构具有抗御地震烈度9度而保持使用功能的能力。不同强度的地震动作用下,钢索与管道的内力分配改变,钢索具有调节结构体系构件受力的重要机能,有限元分析结果与试验结果比较吻合。
The model scaled to be one eighth of the actual cable-suspended structure of long-distance pipelines is made. The experiments and the finite element analysis of the structural models are completed by inputting whitenoise and El Centro ground motion. The experiments show that the natural frequencies of the model decrease with the increase of the shaking forces. The maximal difference is 20%. The maximal earthquake-response of the structure is longitudinal vibration on the top of the tower, acceleration is 1.75g, reduced to 1.62g for the actual structure, the magnification coefficient is 6.03. The earthquake-response of the pipeline is mainly transverse vibration, the maximal acceleration is 1.21g, reduced to 1.12g for the actual structure, and the magnification coefficient is 2.63. In the experiment, the structure elements are undamaged and the structure keeps stable when both the maximal inputting longitudinal and transverse earthquake accelerations reduced to the actual structure are above 0.4g. The experiment shows that the structure can retain operational function under seismic intensity 9. The internal forces of the cables and the pipeline vary with the increasing of the strength of input motions, cables are able to adjust the internal forces of the structural components. The results of finite element analysis correspond well with the experiment.