Safety Assessment Of Inner Suspended And Outer Guyed Holding Poles

The holding pole is used to assemble transmission towers as a kind of important lifting equipment. Although the holding pole has been widely applied in the practical engineering, the design-and construction of the holding pole mainly relys on engineering experience, and lacks of certain theoretical basis. The inner suspended and outer guyed holding pole is a common type of holding pole used in electric transmission and transformation engineering. The safety assessment of the inner suspended and outer guyed holding pole is carried out, which has important engineering significance and can prevent from engineering accidents.The indexes of the safety evaluation of the inner suspended and outer guyed holding pole are established. Safety evaluation indexes include qualitative indexes and quantitative indexes. Qualitative indexes include the factory file, the size of the holding pole model, etc. Quantitative indexes include the perpendicularity, hoisting weight, inclination angle, slenderness, the angle of outer guyed wire/inner suspended rope/lifting rope/control line, the length of inner suspended rope, working height, etc. The numerical simulation for each quantitative index is analyzed. Combining qualitative and quantitative analysis results, comprehensive safety assessment of the entire pole is investigated.The results show that:the perpendicularity is less than 1/1000, hoisting weight is less than the rated weight, inclination angle is less than 10 degrees, slenderness is less than 120, the angle of the outer guyed wire is greater than 45 degrees, the angle of the inner suspended rope is less than 45 degrees, lifting rope angle is less than 15 degrees, control line angle is less than 45 degrees, the length of the inner suspended rope is about 20～30 m, the working height of the pole is around 120 m.In the case which cannot meet the control indexes, the construction plan should include control measures. The operation safety can be guaranteed by reducing the rated hoisting weight. Research results can provide the practical method and basis for the safety assessment of the inner suspended and outer guyed holding pole.