Research on the Slip Model of Main Member Bar Connection of Transmission Tower Using Bolts

To study the slip performance of main member bar connections in transmission towers, 77 groups of bolted main member bar connections were analyzed, and the influence of eight factors, that is, the number of bolts, bolt grade, angle grade, bolt diameter, angle thickness, angle width, preload, and friction factor, on the slip performance of the main member bar connections was studied. Moreover, a slip curve model was established. The results showed that the load-slip curve presented four stages. The pre-slip and post-slip stiffness first increased and then decreased with an increase in the bolt diameter and number. The slip load increased approximately linearly with increases in the bolt pre-tightening force, friction factor, and number of bolts. The ultimate load of the bolted joint was limited by the weaker bearing capacities of the angle steel and bolt group. These findings can serve as a reference for the design of such structures.