Numerical analysis of axially loaded circular high strength concrete-filled double steel tubular short columns

Mizan Ahmed, Qing Quan Liang, Vipulkumar Ishvarbhai Patel, Muhammad N.S. Hadi

Research output: Contribution to journalArticleResearchpeer-review

80 Citations (Scopus)

Abstract

Circular high-strength concrete-filled double steel tubular (CFDST) columns are high performance members where the internal and external steel tubes offer significant confinement to the concrete infill. The confinement remarkably improves the concrete compressive strength and ductility. However, no fiber element models have been formulated for computing the responses of CFDST columns with circular steel tubes filled with high-strength concrete incorporating accurate confinement to the core and sandwiched concrete. In this paper, a new fiber-based numerical model is developed that computes the axial load-strain responses of circular high-strength CFDST short columns under axial loading. Based on existing experimental results, a new confining pressure model is developed for the determination of the confining pressures on the core-concrete in CFDST columns with circular sections. A new strength degradation parameter is also proposed that allows the concrete post-peak characteristics to be quantified. The fiber-based numerical model validated by experimental data is used to assess the responses of high-strength CFDST columns considering important parameters, which include the inner steel tube, external tube diameter-to-thickness ratio and concrete and steel strengths. A simple expression is derived for the estimation of the axial load-carrying capacities of circular short CFDST columns and comparisons with several design codes are made. The proposed fiber-based analysis technique and design equation can accurately determine the responses of short circular high-strength CFDST columns.

Original languageEnglish
Pages (from-to)105-116
Number of pages12
JournalThin-Walled Structures
Volume138
DOIs
Publication statusPublished - May 2019
Externally publishedYes

Keywords

  • Composite columns
  • Concrete-filled double steel tubes
  • High-strength concrete
  • Numerical modeling

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