Degradation of Axial Ultimate Load-Bearing Capacity of Circular Thin-Walled Concrete-Filled Steel Tubular Stub Columns after Corrosion.

Fengjie Zhang,Guo Li,Kejin Wang,Junwu Xia,Zhen Guo,Hongfei Chang

doi:10.3390/ma13030795

Abstract

This work aimed to investigate the effects of steel tube corrosion on the axial ultimate load-bearing capacity (AULC) of circular thin-walled concrete-filled steel tubular (CFST) members. Circular thin-walled CFST stub column specimens were made of steel tubes with various wall-thicknesses. These CFST column specimens were subjected to an accelerated corrosion test, where the steel tubes were corroded to different degrees of corrosion. Then, these CFST specimens with corroded steel tubes experienced an axial static loading test. Results show that the failure patterns of circular thin-walled CFST stub columns with corroded steel tubes are different from those of the counterpart CFST columns with ordinary wall-thickness steel tubes, which is a typical failure mode of shear bulging with slight local outward buckling. The ultimate strength and plastic deformation capacity of the CFST specimens decreased with the increasing degree of steel corrosion. The failure modes of the specimens still belonged to ductile failure because of the confinement of outer steel tube. The degree of steel tube corrosion, diameter-to-thickness ratio, and confinement coefficient had substantial influences on the AULC and the ultimate compressive strength of circular thin-walled CFST stub columns. A simple AULC prediction model for corroded circular thin-walled CFST stub columns was presented through the regression of the experimental data and parameter analysis.

Highlights

Concrete-filled steel tubes (CFSTs) are new composite materials produced by filling steel tubes with concrete
This study aimed to investigate the failure modes and the degradation characteristics of the axial ultimate load-bearing capacity (AULC) of circular thin-walled CFST stub columns made with steel tubes under different corrosion ratios
The AULC of a CFST column is composed of the outer steel tube and the core concrete

Summary

Introduction

Concrete-filled steel tubes (CFSTs) are new composite materials produced by filling steel tubes with concrete. Their working principle is that the stability of the steel tube is immensely enhanced with the addition of hardened concrete. The axial ultimate load-bearing capacity (AULC) of outer steel tube under compression can be substantially improved, and the core concrete can exhibit a high compressive strength and ductility because of the confinement action of the outer steel tube [1,2]. CFSTs have been widely used in various civil engineering projects, such as multi and high-rise buildings, bridge structures, offshore platforms, large-span spatial structures, power transmission towers, and water-retaining walls because of their outstanding working performance [3,4,5,6,7,8].

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