Experimental study and finite element analysis on normal section bearing capacity of steel reinforced concrete special-shaped columns

In order to research the normal section bearing capacity of steel reinforced concrete (SRC) special-shaped columns, 22 specimens were designed for static loading and low cycle reversed loading test, and the failure mechanism was analyzed. A set of computer programs were compiled, and the influences of the loading-angle, steel disposition forms, sectional steel ratio, concrete strength grade and depth-thickness ratio of column limb on the normal section bearing capacity of SRC special-shaped columns were analyzed. Finally comparison of SRC special-shaped columns and RC special-shaped columns on normal section bearing capacity was conducted. The research results show that the failure patterns of SRC special-shaped columns are large eccentric compression, small eccentric compression and axial compression. The sectional strain basically fits the plane-section assumption. The influences of loading-angle and steel disposition forms on the bearing capacity of normal section are very large. Weak loading directions of T-shaped column are 0°, 90° and 315°. Weak loading directions of L-shaped column are 90° and 315°. Weak loading direction of +-shaped column is 0°. The bearing capacity of solid-web steel disposition increases obviously, compared with the open-web steel disposition. The increases of the sectional steel ratio, concrete strength grade and depth-thickness ratio of column limb can improve the normal section bearing capacity effectively. Compared with the RC special-shaped columns, when the sectional steel ratio is no more than 6%, the bearing capacity is increased more than 36%.