Behavior and modeling of seawater sea-sand coral aggregate concrete-filled BFRP tubular columns under eccentric compression

An integrated basalt fiber reinforced polymer (BFRP) tube with longitudinal BFRP bars pre-bonded on the inner wall, which can provide strength in both circumferential and longitudinal direction, was developed in this paper. On this basis, a new type of BFRP tubular column filled with seawater sea-sand coral aggregate concrete (SWCC) was proposed, and its eccentric compressive performance was studied based on experimental tests and numerical modeling. The effects of parameters such as the wall thickness of the BFRP tube, eccentric distance, and pre-bonded BFRP bars on the eccentric compressive performance were analyzed. The results showed that, the greater the eccentricity, the smaller the ultimate load and the ultimate displacement. The ultimate load and displacement increased with the increase of the tube thickness and the reinforcement ratio. The existence of the BFRP bars significantly increased the hoop strain of the specimen under the ultimate load, so that the good hoop mechanical properties of the BFRP tube could be brought into full play. The established numerical model had good accuracy in predicting the load–displacement relationship and the failure modes of the proposed SWCC filled BFRP tubular columns under eccentric compression.