| With the increasing of transmission towers in mine goaf area,the influence of the foundation deformation on transmission tower becoming increasingly significant.The foundation of transmission tower will be deformed such as settlement and inclination after surface deformation occurs in mine goaf area,which results in the deformation of components and even caused the deflection of the whole tower.Further more,the serious accidents such as overturning or collapse of the tower may occur,which will affect the safety and stability of the whole power grid system.The transmission tower is spatial truss structure,which is consisted of hot-rolled equal-angle steel members connected by bolts.The connection eccentricity is inevitable at its bolted joints.Therefore,the angle steel members will be affected by both the axial load and the additional bending moment caused by the joint eccentricity.In this paper,the joint effects in transmission tower are studied.A refined finite element model of bolted joints is established.The additional bending moment of bolted joints under axial load is obtained through numerical analysis.The relationship between axial force and bending moment and the equivalent eccentricity are given.The simulation method of joint effect is given by comparing the results with the bolted joint test results.Full-scale test of transmission tower body is carried out and compared with the simulation results,which verifies the correctness of the bolted joint simplified model.The deformation,axial force and ultimate bearing capacity of transmission towers in mine goaf area under different foundation deformation conditions are presented,which provides a theoretical basis for the safety assessment of transmission lines in mine goaf area. |
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