EFFECT OF BOLT JOINT ON THE BEHAVIOUR OF TRANSMISSION TOWER WITH NON-UNIFORM SETTLEMENT

In some instance for a transmission tower still functioning well with large non-uniform settlement, the transmission tower failure was predicted by conventional structure analysis software. Firstly, the experimental slippage behavior of representative bolted joints in a transmission tower is investigated and applied to study the behaviour of a transmission tower with non-uniform settlement, in which the load eccentricity in the transmission tower component is also considered. Secondly, the displacement, strain and tilt angle are measured to show the deformation behaviour of the transmission tower under non-uniform settlements. Finally, to improve the existing bolt slippage models, a slippage beam model and a slippage eccentric bar model are developed based on ANSYS software, and the FEM simulation results are compared with the test ones. It is found that bolt slippage causes the redistribution of the internal forces of the members in a transmission tower and obviously increases the deformation of a transmission tower, compared to the ideal bolted connection conditions. The simulation results of the model with slippage and eccentricity agree well with the experimental data. The slippage beam model not only can better reflect the deformation characteristics of a transmission tower, but also can reduce the work load of the existing bolt slippage model when introducing the bolted joint effect into the finite element analysis.