The post-buckled performance of cross-braced single angles was experimentally determined. The results of this study will be used by the Bonneville Power Administration for the analysis of member performance in transmission towers. Compression tests were conducted on different sizes of }ong a;·e;les ;.ith varying tensions in the cross brace ar,gl es. These compression angles had either ball-ball or f i x e d -f i x e d 2 :1 d co n d i t i on s . To study the effects of the restraint p;-ovided by

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... the cross brace tension angle, some test. s on short single :: pan angles with ball-ball, baJl-fixed a1d ball-partial restraint joints were also conducted. evaluated The performance of compression test angles were by the axial load vs axial shortening characteristics. Axial loads were read off the digital display of the MTS machine. from dial gage readings. Axial shortening was obtained Results of this study show that the magnitude of the tt'>nsion in the cross brace angle does not affect the post buckled performance of the compression angle. Angles with lower slenderness ratios have higher peak loads but their load res::..sting capacity diminishes with increasing axial shortening. The post buckled performance of a cross brace compression angle is equivalent to that of the same size angle but of half the length, with a partial restraint joint at the intermediate support. Utilizing the results of this study, an analytical model was developed for predicting the performance curve for any compression angle given its effective slenderness ratio dnd cross sectional area.