Abstract
Numerous studies have been carried out on the axially loaded circular concrete-filled steel tube (CCFST) stub columns. However, to date, no clear evaluation criterion for the compatibility of its design parameters has been established. In the present study, the compatibility of the design parameters (concrete compressive strength , steel yield strength , diameter D and thickness of steel tube t) of axially loaded CCFST stub columns was quantitatively investigated in terms of the contribution of the composite actions to the axial bearing capacity of the columns. The composite ratio was proposed as an indicator to represent the effectiveness of the composite actions. A numerical framework of the determination of was established, making use of a series of existing widely recognized constitutive models of structural steel and concrete. Some modifications were carried out on these models to ensure the numerical stability of the presented analysis. Moreover, the rationality of the combined use of these models was verified. The analytical results show that excessive or very small ratio should be avoided in design. Meanwhile, the combined use of low-strength steel and high-strength concrete should be avoided. A table of optimal ratios corresponding to different material strength matches was provided for designers. Finally, an optimization of the design parameters using the proposed method and the existing design specification was performed.
Highlights
Over the past two decades, concrete-filled steel tube (CFST) columns have been experimentally and theoretically verified to have far superior strength, ductility, and energy absorption capacity compared to hollow thin-walled steel columns and reinforced concrete (RC) columns [1]
Because of the above advantages, composite structural columns based on the similar concept, such as recycled aggregate concrete-filled steel tube [10], concrete-filled aluminum alloy tube[11], lightweight concrete-filled steel tube [12], stirrup-confined concrete-filled steel tube [13], and concrete-filled dual steel tube columns [14] were proposed in recent years to satisfy different design objectives for low carbon, good appearance, being lightweight and high strength, etc
Numerous researchers have contributed to the testing of CFST columns with different dimensions [18,19], material strength grades [20,21], and cross-section types [22,23] over the past three decades and have proposed empirical formulas [24] for calculating the axial compression capacity and effective limitations of design parameters such as the aspect ratio and slenderness-to-thickness ratio
Summary
Over the past two decades, concrete-filled steel tube (CFST) columns have been experimentally and theoretically verified to have far superior strength, ductility, and energy absorption capacity compared to hollow thin-walled steel columns and reinforced concrete (RC) columns [1]. It was found that the performance of axially loaded CFST columns is heavily affected by the diameter-to-thickness ratio (width-to-thickness ratio for rectangular columns) and heightto-diameter ratio (width-to-height ratio for rectangular columns) Following this insight, numerous researchers have contributed to the testing of CFST columns with different dimensions [18,19], material strength grades [20,21], and cross-section types [22,23] over the past three decades and have proposed empirical formulas [24] for calculating the axial compression capacity and effective limitations of design parameters such as the aspect ratio and slenderness-to-thickness ratio.
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