PSEUDO-STATIC TEST AND STATIC ELASTO-PLASTIC ANALYSIS OF MIDDLE FRAME WITH SOLID STEEL REINFORCED CONCRETE SPECIAL-SHAPED COLUMNS

In order to study the mechanical properties of a middle frame with solid steel reinforced concrete (SRC) special-shaped columns, the pseudo-static test was carried out on a 1/2.5-scaled model of a two-bay and three-story middle frame consisting of reinforced concrete beams and solid SRC special-shaped columns. The main results such as failure pattern, hysteretic loop and characteristic values of load and displacement were obtained. Based on the experiment, the methods to build the elasto-plastic analysis model of the experimental frame using SAP2000 program were comparatively discussed. It is shown that the analytical model built by the fiber plastic-hinges is more effectively to analyze the elasto-plastic behavior of the special frame. Parameter analyses were conducted to investigate the influences on the static elasto-plastic behavior of the solid SRC middle frame with special-shaped columns, in which 4 main factors including the height-thickness ratio of column limb, the steel strength, the concrete strength and the beam-column yield bending moment ratio were considered. Some laws were concluded as follows: with the increase of the height-thickness ratio of column limb or the beam-column yield bending moment ratio, the horizontal bearing capacity of the frame increases obviously;with the increment of the height-thickness ratio of column limb, the stiffness of the frame enlarges apparently. The ductility of the frame is almost unchanged when the height-thickness ratio of column limb, the steel yielding strength or the beam-column yield bending moment ratio change.