Analysis Study on Fire Performance with Internal Anchored Concrete Filled Steel Tube Columns According to Percent of Steel-Fibers

This paper presents experimental studies on the post-fire performance of concrete-filled steel tube (CSFT) columns under uni-axial load. The structural responses and axial load capacity of CSFT columns after exposure to elevated temperatures are investigated and discussed. All of the specimens are 750 mm in height, the nominal cross-section of the specimen is 150 mm x 150 mm, and have cylinder compressive strength of 18 MPa. The primary test parameters to be measured during the uni-axial compression test are wall thicknesses of the square tube (3.0 mm, 4.5 mm and 6.0 mm) and three different exposure to elevated temperatures (400°C, 600°C and 800°C). The results showed that the load-axial shortening relationship of the CSFT columns have a linear elastic response up to 80-90% of axial load capacity. After the axial load capacity is reached, the load-axial shortening curves are rarely becoming a nonlinear manner. It is also shown that the axial load capacity and ductility of the post-fire test columns are decreased significantly compared to the columns at ambient temperature, depending mainly on the elevated temperature. In addition, by comparing the axial load capacity of the test results with those obtained from the ACI design equation, the comparison results indicate that calculation formula in ACI code unconservative predicts the axial load capacity of the CSFT columns after exposure to elevated temperatures. Finally, the residual strength ratios are modified to both strength of concrete and steel tube under ambient temperature, and analyzed to evaluate the effect of post-fire behavior on the axial capacity of CFST columns.

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Experimental Study on Flexural Behavior of Concrete Filled Steel Tube Girder Bridges

IABSE Symposium, Weimar 2007: Improving Infrastructure Worldwide ◽

10.2749/weimar.2007.0624 ◽

2007 ◽

Author(s):

Won Jong Chin ◽

Jae Yoon Kang ◽

Eun Suk Choi ◽

Jung Woo Lee ◽

Byung Suk Kim

Keyword(s):

Experimental Study ◽

Steel Tube ◽

Flexural Behavior ◽

Concrete Filled Steel Tube ◽

Girder Bridges

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A thermal-driven method based on Brillouin fiber-optic sensors for the quantitative identification of subsurface cavities in concrete-filled steel tube structures

Journal of Civil Structural Health Monitoring ◽

10.1007/s13349-020-00464-7 ◽

2021 ◽

Author(s):

Shilin Gong ◽

Xin Feng ◽

Guanhua Zhang

Keyword(s):

Fiber Optic ◽

Fiber Optic Sensors ◽

Steel Tube ◽

Concrete Filled Steel Tube ◽

Quantitative Identification ◽

Subsurface Cavities

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Flexural behavior of composite concrete-filled steel tube roof structure under symmetrical concentrated loads

Structures ◽

10.1016/j.istruc.2021.03.047 ◽

2021 ◽

Vol 32 ◽

pp. 1250-1259

Author(s):

Lianguang Wang ◽

Xue Li ◽

Bailing Chen ◽

Haiyang Gao

Keyword(s):

Steel Tube ◽

Flexural Behavior ◽

Concentrated Loads ◽

Concrete Filled Steel Tube ◽

Roof Structure

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Stone prism encased concrete-filled steel tube columns subjected to axial compression

Structures ◽

10.1016/j.istruc.2021.05.058 ◽

2021 ◽

Vol 33 ◽

pp. 1853-1867

Author(s):

Yong Ye ◽

Yang Liu ◽

Zi-Xiong Guo ◽

Rachel Chicchi

Keyword(s):

Axial Compression ◽

Steel Tube ◽

Concrete Filled Steel Tube

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Shear response of steel fiber reinforced recycled concrete-filled steel tube columns

Advances in Structural Engineering ◽

10.1177/13694332211009322 ◽

2021 ◽

pp. 136943322110093

Author(s):

Zhenzhen Liu ◽

Yiyan Lu ◽

Shan Li ◽

Jiancong Liao

Keyword(s):

Axial Compression ◽

Steel Fiber ◽

Steel Tube ◽

Shear Capacity ◽

Recycled Concrete ◽

Recycled Aggregate ◽

Superposition Method ◽

Fiber Reinforced ◽

Concrete Filled Steel Tube ◽

Shear Span

A comprehensive study of the shear characteristics of steel fiber reinforced recycled concrete-filled steel tube (SRCFST) columns is conducted. 50 CFST stub columns are tested with the variables of steel tube diameter-thickness ratio ( D/t), shear span-to-depth ratio (λ), axial compression ratio ( n), and concrete mix. Two types of cements, three recycled aggregate percentages, three water-cement ratios, and three steel fiber contents are considered in design of concrete mixes. The experimental results show that SRCFST columns present the coincident shear behavior of the ordinary CFST columns. As λ is increased, shear resistance shows a downtrend, while the flexural strength presents an increasing trend. Imposing axial compression or thickening steel tube contributes to an adequate safety margin in plastic period. Based on the contributions superposition method, a predicted model of the shear capacity of SRCFST columns is proposed in consideration of shear-span ratio, axial compression, and self-stress.

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