Experimental tests of tension connections of steel angle sections of lattice transmission towers

Abstract

In the present paper, the results of experimental tests of bolted connections of angle specimens subjected to tension and connected by one leg are presented. Structural members of such type are commonly applied to the steel lattice supports of overhead electrical lines. The bolted connections of angles connected by one leg to gusset plates are in tension and additional bending moment that results from the eccentricity of the bolt group. The majority of available existing experimental and numerical investigations regarding the bolted connections of steel angles in tension have been conducted using mostly short specimens. Within this paper, the influence of the specimen length on the behaviour of angles connected by one leg in tension is shown on the basis of the comparison of the results from the experimental tests of shorter and longer specimens of the same size of angle section. Equal-leg angles in two cross-section dimensional groups – L90 × 6 and L120 × 8, and of two lengths: 600 mm and 1500 mm were tested. A basic test included determining the destructive force, elongation of a specimen and its deflections. In the case of some specimens, the tests were extended to include strain measurements in characteristic places of the angles – in the middle of the length and in the bolted connection zone. The conclusions from the conducted experimental tests confirm that the length of a specimen has an impact on the results, with a greater effect observed in angles with larger cross-sections, and thus with a greater load eccentricity.