STUDY ON THE ECCENTRIC COMPRESSIVE PERFORMANCE OF BASALT-FIBER REINFORCED RECYCLED AGGREGATE CONCRETE-FILLED SQUARE STEEL TUBULAR STUB COLUMNS

To study the eccentric compressive performance of basalt-fiber reinforced recycled aggregate concrete-filled square steel tubular stub columns, eight specimens with different replacement ratios of recycled coarse aggregates, basalt fiber dosages, recycled aggregate concrete strength grades, and eccentricities were tested under eccentric static loading. The failure process and modes were observed. The load-displacement curves, load-strain curves and a series of important relation curves were obtained. The influence trend of the design parameters on the strengths of the specimens was analyzed. A finite element model under eccentric compression was established. The design method for calculating the eccentric compression strength of the specimens was suggested. It is shown that the failure process is made up of an elastic stage, an elastic-plasticity stage and a plastic-decline stage. The shapes of the load-deflection curves of all specimens were similar. The lateral deflection of the columns increased rapidly after reaching the peak load. The peak strengths of the specimens decreased with the increase of the replacement ratio and eccentricity, and increased with the increase of the core recycled aggregate concrete strength grade. The finite element model of a basalt-fiber reinforced recycled aggregate concrete-filled square steel tubular stub column was established, which can effectively analyze the whole process of its eccentric compression.