Substructure Experimental Research On Q460 High-Strength Angle With Eccentric Load At One End

In recent years,electric power projects of our country has developed quickly. It will call for higher requirements on steel intensity and structural design of electric transmission towers.High-strength (Q460) steel-angle members have the high load-carrying capacity,utilizing them in transmission towers is of great significance to increasing economical efficiency and advanced technology.The bulk of the hot-rolled single-angle members in tower structures of overhead transmission line are eccentric compression. The researchs of angle struts eccentricity at both ends are more than that of angle struts eccentricity at one end. The action line of the force does not through centre of section of the angle struts eccentricity at one end,the end supporting conditions are difficult to judge,and mechanical properties are very complex,so,which bearing should be used in single-strut tests is difficult to determine. Domestic single-strut tests tend to use the ball bearing or knife-edge bearing at the present time. Whether these bearings are able to simulate the actual mechanical behavior and constraints is uncertain.To analyze mechanical behavior and the ultimate bearing capacity of Q460 high-strength equal-leg angle steel struts with an eccentric load at one end under actual project boundary condition, the angles are placed in the substructures similar to the transmission tower cross arm and failure static test of two substructures are conducted,and finite elements modeling analysis was done at the same time. The results are compared with single-strut tests and some suggestions to improve the specifications will be offered in this paper in order to make researchs more comprehensive and reliable.Experimental studies indicate that:Most single-angle with small slenderness were controlled by local buckling while it was under eccentric load at one end, deformation concentrated in the eccentric side of the connected leg, and the large members were controlled by flexural-torsional buckling. Mechanical behavior and bearing capacity of the angles in the substructures is the same as the single-strut's. Therefore, the ball bearing used in single-strut tests can almost imitate the actual end supporting conditions. The calculation basis on ASCE10-1997 agreed well with the experimental results, so it can provide a basis for design of high-strength angle, but it was over-conservative on large slenderness angles, according to the test results, the revised formulas of it were proposed:KA= 45+0.47λ,it is a reference for design.