Flexural Performance of High-strength Prestressed Concrete-encased Concrete-filled Steel Tube Sections

Abstract

The sections composed of concrete and steel, which include concrete-encased concrete-filled tubes, generally have defects due to the low tensile strength of concrete. Therefore, an appropriate method was used for the combination of concrete-filled tubes (CFT) and prestressing strands which is encased in concrete. The conventional design guidelines are commonly developed for materials with normal strength thus further investigation is required to be conducted for sections with high-strength materials. In order to develop the design process, high-strength concrete and steel have been utilized in this study to examine the effects of steel and concrete strengths on the core concrete confinement, sectional size and flexural behavior of high-strength prestressed concrete-encased CFST (HS-PCE-CFST) beams. Hence, a total of thirteen HS-PCE-CFST beams were modeled via ABAQUS finite element software. The main variables include the steel tube yield strength, compressive cylinder strength of the core and outer concrete and the steel tube diameter to section width ratio. Furthermore, experimental results were employed to verify the finite element model. The bending moment, ductility, flexural stiffness and failure mode of beams are also examined. The results confirm that among the compressive strength of the outer and core concrete and the steel tube yield strength, change in the outer concrete compressive strength has a greater effect on the change of flexural parameters, also increasing the ratio of steel tube diameter to section width causes a minor increase in the ultimate bending moment and serviceability level flexural stiffness, but a major escalation in the initial flexural stiffness.

Experimental Study on Compressive Behavior of Concrete-filled Double-skin Circular Tubes with Active Confinement

“…Furthermore, Yagishita et al [25] concluded that the absorption of energy, strength, and ductility of CFDST columns than CFT columns enhanced when they were subjected to axial loading and cyclic loading. Rahmani et al [19] examined CFTs and CFDSTs cyclically and reached identical conclusions. Hence, the role of CFDSTs in the earthquake-affected becomes essential.…”

“…The steel tube of concrete-filled (CFST) columns has *Corresponding Author Institutional Email: m-naghi@nit.ac.ir (M. Naghipour) become popular in constructing tall buildings amongst these measures recently. One of the reasons is that CFST columns performance is superior to columns of ordinary RC under torsion [12,13], under uni-axial load [14][15][16][17][18], and under flexure [19][20][21], based on experimental and theoretical research. Several examples of composite structures with CFST columns in circular or square forms, as external or internal structural members, are built.…”

Structural behavior of prestressed self‐compacting concrete‐encased concrete‐filled steel tubes beams

“…23,24 There has been extensive research on the compressive behavior of members including CFST and RC elements, but the flexural and shear behavior of these members have not been subject to a comprehensive study. [25][26][27][28][29][30][31][32] An et al conducted an experimental 33 and analytical 34 study of concrete-encased CFST eccentrically loaded columns. They concluded that CFST improved stiffness, ductility, and the ultimate strength of the section.…”