Experimental and Numerical Response of Compressed Equal-Leg Steel Angle Members with Different Anchorage Lengths

Reliable tests of compressed steel members require appropriate representation of boundary conditions. This study examined the global response of compressed hot-rolled equal-leg steel angle members with three end-fixture configurations. Nine L50 × 50 × 4 specimens were tested with anchorage lengths of 50, 100, and 150 mm. Because increasing anchorage length reduced the unsupported member length, the observed differences reflect the combined effect of both parameters. Displacements and longitudinal strains were measured using Digital Image Correlation and strain gauges, respectively, and the tests were supplemented by finite element analyses. The configurations produced differences in maximum load and global displacement, although maximum load varied non-monotonically with anchorage length. At the investigated load levels, local longitudinal strains were similar, whereas global displacements differed. The K-5 specimens deformed in the direction opposite to the K-10 and K-15 specimens. Baseline numerical analyses reproduced the observed directions for K-10 and K-15, but not K-5. Reversing the sign of the initial imperfection reproduced the K-5 direction, supporting an interpretation involving two branches of the same global buckling mode; however, the cause of branch selection remained unresolved. The results show that end-fixture configuration should be considered when interpreting experimental and numerical assessments of compressed steel angle members.