In order to improve the wind-bearing capacity of transmission tower

this paper proposed a T-section combined angles’ retrofitting method applied to diagonal members and studied the capacity of the strengthened members.Firstly

the optimization analysis of the retrofitting method was carried out

and the influence the stiffness and bearing capacity of the strengthened members was studied

including the width

length

thickness and the number of plate were considered.Then the effectiveness of the retrofitting method was tested by the load-bearing capacity tests of angle members and strengthened members.Finally

the calculation model of the compression-flexural capacity of the strengthened members was established

the theoretical capacity of the strengthened members was calculated and compared with that of numerical analysis.The results show that the stiffness and bearing capacity of the strengthened members are mainly related to the dimensionless coefficient determined by the length and number of plate.Compared with angle member

the bearing capacity of the strengthened member is increased by nearly 2.5 times.The theoretical results match well with that of the finite element method.