Abstract
The behavior of H-shaped honeycombed stub columns with rectangular concrete-filled steel tube flanges (STHCCs) subjected to axial load was investigated experimentally. A total of 16 specimens were studied, and the main parameters varied in the tests included the confinement effect coefficient of the steel tube (ξ), the concrete cubic compressive strength (fcu), the steel web thickness (t2), and the slenderness ratio of specimens (λs). Failure modes, load-displacement curves, load-strain curves of the steel tube flanges and webs, and force mechanisms were obtained by means of axial compression tests. The parameter influences on the axial compression bearing capacity and ductility were then analyzed. The results showed that rudder slip diagonal lines occur on the steel tube outer surface and the concrete-filled steel tube flanges of all specimens exhibit shear failure. Specimen load-displacement curves can be broadly divided into elastic deformation, elastic-plastic deformation, and load descending and residual deformation stages. The specimen axial compression bearing capacity and ductility increase with increasing ξ, and the axial compression bearing capacity increases gradually with increasing fcu, whereas the ductility decreases. The ductility significantly improves with increasing t2, whereas the axial compression bearing capacity increases slightly. The axial compression bearing capacity decreases gradually with increasing λs, whereas the ductility increases. An analytical expression for the STHCC short column axial compression bearing capacity is established by introducing a correction function ( w ), which has good agreement with experimental results. Finally, several design guidelines are suggested, which can provide a foundation for the popularization and application of this kind of novel composite column in practical engineering projects.
Highlights
Conventional multistory light steel structures have been widely applied for construction and reconstruction projects [1,2,3,4]
To reduce the deflection of composite beams, prestressing tendons are arranged in the steel tubes of lower composite beam flanges, whose tension and anchorage are realized at the ends of the integral joint. e concrete-filled steel tube (CFST) sectional form is adopted as frame column flanges, where the concrete prevents local steel tube buckling, while the steel tube continuously restrains the concrete; the concrete experiences three-dimensional compression, and interaction between the steel tube and concrete can be fully utilized
Considering coupling effect of CFST flanges and honeycombed webs, this study proposes an analytical expression by means of introducing correction function (ω) and influence factor (η) and modifies (4) as follows: Nu Nu1 + ω(η)
Summary
Conventional multistory light steel structures have been widely applied for construction and reconstruction projects [1,2,3,4]. Bao [24] proposed a practical method to calculate equivalent slenderness ratios for CFST latticed columns, and an analytical expression was derived to predict CFST latticed column bearing capacity with K-shaped joints. Liu et al [27] experimentally studied the effects of different parameters on column stability under axial compression for 6 L-shaped and 12 T-shaped CFST stub columns, and corresponding analytical expressions were proposed for stability bearing capacity based on experimental and finite element (FE) analysis results. Most of the previous research studies were mainly concentrated on beams with different flanges and CFST columns with various sections, and it seems that there is seldom research reported on the performance of H-shaped honeycombed columns with rectangular concrete-filled steel tube flanges (STHCCs). An analytical expression was derived to calculate ultimate bearing capacity of the stub columns based on the measured experimental statistics
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