内置式钢锚箱索塔锚固区受力与参数分析

内置式钢锚箱索塔锚固区模型试验结果表明结构强度足够,但混凝土外端壁和内侧壁均出现裂缝,且外端壁开裂荷载较低.根据索塔锚固区的变形协调关系,分别对矩形和圆形索塔的斜拉索水平分力在钢锚箱与混凝土塔壁之间的分配比例、外端壁和内侧壁的混凝土应力进行理论分析,理论分析结果与试验结果吻合.对矩形和圆形索塔的水平力分配比例和混凝土应力进行参数影响分析,分析结果表明调整索塔长宽比、塔壁厚度比、钢锚箱拉板面积等能改善塔壁混凝土的受力.对相当规模的内置式钢锚箱圆形和矩形索塔锚固区的结构受力性能进行对比分析,结果表明矩形索塔略优于圆形索塔.建议采取措施改善混凝土外端壁局部受力状况.

Mechanical and Parameter Analysis of Cable-to-Pylon Anchorage Zone with Built-in Steel Anchor Box

The results of model test for the cable-to-pylon anchorage zone with built-in steel anchor box indicate that the structural strength of the anchorage zone is sufficient, however, the cracks appear in both the outer end and inner concrete walls of the pylon and the load causing the cracks in the outer end wall is rather low. In accordance with the relationship of deformation coordination in the anchorage zone, the distribution proportion of the horizontal component of stay cables in between the steel anchor boxes and the concrete walls of the rectangular and round pylons and the concrete stress in the outer end and inner walls are respectively theoretically analyzed and it is found that the results of the theoretic analysis well agree with those of the test. The a-nalysis of structural parameter influence is also made for the distribution proportion of the horizontal force and the concrete stress of the two kinds of the pylons. The results show that the adjustment of the length-to-width ratio, wall thickness ratio and the tension plate areas of the steel anchor boxes can improve the mechanical behavior of the concrete of the pylon walls. The comparative analysis further made for the mechanical behavior of the considerable scale anchorage zones with built-in steel anchor boxes of the two kinds of the pylons show that rectangular pylon is slightly superior over the round one and it is proposed that the proper measures should be taken to improve the local force conditions of the concrete end walls.