Stiffness Analysis of Recycled Self‐Compacting Concrete‐Filled Circular Steel Tubular Columns under Eccentric Compression

Abstract

In this study, twenty-one recycled self-compacting concrete-filled circular steel tubular (RSCFCST) columns are designed and tested under eccentric compression. The studied parameters including the replacement ratio of the recycled coarse aggregate (RCA), strength grade of concrete, eccentricity, and length-diameter ratio L/D of specimens are considered. The load-stiffness curves of the specimens are obtained by observing the whole process of loading, and the effects of various parameters on the stiffness of the specimens are analyzed. Test results demonstrate that the RSCFCST short columns L/D≤4 under eccentric compression exhibit drum-like bending failures, while the RSCFCST long columns L/D>4 under eccentric compression experience the global flexural buckling failure modes. With the replacement ratio of RCA, the length-diameter ratio or eccentricity increases, and the bearing capacity of specimens under eccentric compression decreases. However, the increase in the strength grade of concrete increases the bearing capacity. The stiffness of the RSCFCST columns under eccentric compression gradually increases as the strength grade of concrete increases, while the eccentricity had an adverse effect on stiffness of specimen. With the increase of load, the increase of the length-diameter ratio would accelerate the stiffness degradation of specimen. The effect of the replacement ratio of RCA on stiffness of specimen in the elastic stage is not obvious. A validated FE model is employed to conduct parametric studies to widen the available test results. Additionally, an analytical model for predicting the effective stiffness of the RSCFCST columns under eccentric compression is proposed based on the moment magnifier method, and verification of this method is performed using the test data and FE analysis.

Bearing Behavior of H‐Shaped Honeycombed Steel Web Composite Columns with Rectangular Concrete‐Filled Steel Tube Flanges under Eccentrical Compression Load

“…Chen et al [9] studied the influence regularity of different parameters on eccentrical compression test of 18 concrete-filled square steel tube columns with spiral stirrups and derived the calculation formula of eccentrical compression bearing capacity of these types of columns. Twenty-one recycled self-compacting concrete-filled circular steel tubular (RSCFCST) columns were tested subjected to eccentric compression by Yu et al [10], and bearing capacity of these kinds of composite columns under eccentric compression was obtained systemically; finally, an analytical model for predicting the effective stiffness of RSCFCST columns under eccentric compression was proposed based on the moment magnifier method. In 2017, Ji et al [11] investigated the eigenvalue buckling behavior of 29 STHCCs by ABAQUS software.…”