Experimental investigation for the behaviour of battened beam-columns composed of four equal slender angles

This study presents series of compression tests on battened columns that are composed of four equal slender angles. The angles are formed by bending thin steel sheets, such that the legs outstand width–thickness ratio is slender. Twenty specimens varied in their plate element width–thickness ratio as well as covered short and medium member slenderness were tested. The angles were assembled by batten plates by means of bolts. Measurements of residual stresses and geometrical imperfections were carried out. Moreover the specimens were simulated by a finite element model using shell element that accounts for both geometric and material non-linearities. The measured geometric imperfections and residual stresses were included in the numerical model. Finally, the test results have been compared with those of non-linear finite element model, and also with the predicted ultimate strengths determined by the American and European specifications. Results show that the interaction between slender outstanding width–thickness ratios, overall angle slenderness and overall column slenderness decrease the strength of battened columns. Also, the results of bolted finite element model were in reasonably good agreement with test results that neglect the effect of bolt holes.