基于主材防屈曲的输电塔新型抗风加固方法研究

Research on new wind⁃resistance strengthening method of power transmission tower by preventing main material buckling

输电塔属于高柔结构,风致响应敏感。主材角钢作为输电塔的主要构件,其承载能力特别是受压抗失稳能力是影响输电塔抗风性能的主要因素。以提高主材角钢受压状态下的防屈曲能力为目的,兼顾考虑降低开螺栓孔对原主材的损伤,提出一种新型加固方法。并通过对6个足尺角钢构件进行加载试验,检验该新型方案的加固效果;分析不同加固参数对提升主材性能的影响;采用有限元方法对试验进行数值模拟,确立合理的有限元建模方法,为输电塔整塔加固方案设计提供依据。结果表明:该方案能够大幅提高构件的抗压承载力,并有效改善构件的延性;端部螺栓数目对加固效果影响明显;确定了抱箍间距的合理取值;拼接副主材的应力滞后对加固效果基本没有影响。

Power transmission tower is high⁃rise and flexible structure,which is sensitive to wind loading.The bearing capacity,especially the compressive stability capacity of the steel angles used for main materials affects the wind⁃resistance performance of power transmission tower.To improve the anti⁃buckling capacity of the steel angles used for main materials under compressive loading,together with the consideration on decreasing the additional damage to the existing steel angle due to the hole⁃opening for the connecting bolts,a new strengthening method was proposed.Loading tests were conducted on six full⁃scale steel angle specimens to validate the strengthening effectiveness and examine factors that may affect the strengthening effectiveness.Finite element method analyze was also conducted simulating the loading tests to establish a reliable modeling method,which is essential for the strengthening design of the whole tower.It is revealed that the proposed new method can largely improve the bearing capacity,together with the ductility of the steel angles.Number of the bolts at the element ends for connecting the existing and installed angles remarkably affects the strengthening effectiveness.A reasonable value of the distance between the steel hose clamps was also proposed.Moreover,no clear effectiveness of stress lagging of the posted installed steel angle on strengthening effectiveness is observed.