Mechanical performance of concrete-filled square steel tube stiffened with PBL subjected to eccentric compressive loads: Experimental study and numerical simulation. (April 2020)

• Record Type: Journal Article
• Authors: Liu, Jun-ping; Yang, Jian; Chen, Bao-chun; Zhou, Zong-yuan
• Is Part Of: Thin-walled structures. Volume 149(2020)
• Publication Date: 2020-04
• Subjects: Concrete-filled square steel tube -- PBL stiffeners -- Flexural behavior -- Eccentric compressive behavior -- Experimental study -- FEA; Thin-walled structures -- Periodicals; 690.1
• DOI: 10.1016/j.tws.2020.106617
• Languages: English
• ISSNs: 0263-8231

Abstract

Abstract: This paper describes an experimental study on the flexural and eccentric compressive behavior of concrete-filled square steel tube (CFSST) beam-columns stiffened with PBL stiffeners. Three types of CFSST beam-columns were fabricated and tested under the flexural moment and eccentric compressive load. Among the three types of columns, the two types of columns were strengthened with the PBL and steel plate stiffeners; the other type of columns was not strengthened. In addition, extensive finite element analyses (FEA) were carried out to evaluate the stress distribution. Flexural test results show that failure modes of specimens without stiffeners were different from specimens with the PBL or steel plate stiffeners. The results also demonstrate the distribution of cracks in the concrete was affected by stiffeners and the columns with the PBL stiffeners have the most uniformed crack distributions. The capacity improved by the PBL stiffeners was insignificant. However, the flexural stiffness of the specimen stiffened with the PBL stiffeners was about 20% larger than the unstiffened specimen. Eccentric compressive load test results show the capacity of specimen with the PBL stiffeners was 6.95% larger than the unstiffened specimen. The eccentric compressive capacity decreased with the increase of the eccentricity ratio or slenderness ratio. FEA results show that stiffeners can effectively improve the mechanical behavior of CFSST specimens under bending and eccentric compressive loads. Highlights: Distribution of cracks in the concrete was affected by stiffeners. Capacity improved by the PBL stiffeners was insignificant, but flexural stiffness was about 20% larger. Flexural capacity reaches the largest when spacing of aperture in the PBL stiffeners is twice the aperture diameter.