Abstract: In order to study the mechanical properties and deformation characteristics of the double angle steel parallel reinforcement method connected by fixtures on towers, this paper conducts multi-sensitive parameter numerical simulation experiments on two types of double angle steel section composite components arranged in parallel axes. Based on the finite element test results and relative slip theory, a local buckling ultimate bearing capacity correction formula for double angle steel parallel composite components connected by fixtures is derived based on the plate shell elastic theory. The results show that the load-bearing performance of square section composite components is better than that of cross section components, with their ultimate bearing capacities increased by 14.1% to 21.2% and 1.64% to 12.57%, respectively. When the fixture connection parameters that control the force coordination between the main and auxiliary materials exceed the threshold, square section composite components are prone to transition from torsional instability to local buckling instability. The main instability modes of cross section composite components fall in overall bending and local buckling. The ultimate bearing capacity and stress coordination of the components increase slightly with the increase of frictional force or bolt preload force. The theoretical calculation correction formula derived based on deformation characteristics and slip characteristics can accurately predict the ultimate bearing capacity results of reinforcement measures for double angle steel sections with fixture connections that experience local instability, providing reference for tower reinforcement design.

Key words: double angle steel section, parallel reinforcement, numerical simulation, bearing capacity, calculation method for local buckling bearing capacity