Seismic behavior of polypropylene fiber reinforced rubber concrete-filled circular steel tubular columns

Abstract

In this study, the seismic behavior of polypropylene fiber reinforced rubber concrete-filled circular steel tubular columns subjected to low cyclic loading was investigated. The effects of varying rubber content, slenderness ratio, axial compression ratio, and steel content on specimen damage were analyzed. Digital Image Correlation (DIC) and Acoustic Emission (AE) instruments were utilized to monitor the full-field strain on the surface of the specimens and the generation and development of internal concrete cracks. A fiber modeling method was developed for calculating the compression bending bearing capacity of the columns. The results indicated a uniform failure pattern, primarily located at the column base. Adding rubber powder decreased the bearing capacity of the specimen, yet enhanced their energy dissipation capacity and ductility. Higher axial compression ratio led to early failure in the steel tube, with the slenderness ratio significantly affecting seismic performance. The calculation methods according to GB 50936–2014 (CECS 254–2012) and DL T5085–1999 showed higher accuracy than other codes, with average values of 0.558 and 0.576, and standard deviations of 0.067 and 0.089, respectively. The variation coefficient for the calculation method in GB 50936–2014(CECS 254–2012) was 12.02%, lower than that of DL T5085–1999. The proposed fiber modeling method demonstrated superior calculation accuracy, with an average value of 0.957, a standard deviation of 0.032, and a variation coefficient of 3.29%.