Size-dependency of concrete-filled steel tubes subject to impact loading

Mahsa Mirmomeni, Amin Heidarpour, Xiao Ling Zhao, Riadh Al-Mahaidi, Jeffrey A. Packer

Research output: Journal article publicationJournal articleAcademic researchpeer-review

26 Citations (Scopus)

Abstract

With the increasing trend towards using concrete-filled steel tubes (CFST) in civil structures, understanding their mechanical properties under impact loads has attracted the interest of researchers. The dynamic properties of concrete confined by steel tubes are size-dependent. An experimental program was carried out to investigate the relation between the size and impact response of CFST sub-samples. High-strain-rate tests were conducted on specimens made from self-consolidating normal concrete confined by mild steel tubes. To take into account the stress uniformity and confinement effects in the specimens, various height-to-diameter ratios (H/D) and diameter-to-tube-wall thickness ratios (D/t) were considered. Dynamic increase factors (DIFs) were derived as the ratio of the material strength at high strain rate to those of the same size under quasi-static loading conditions. The results were compared to two sets of reference tests, namely unconfined concrete and hollow steel tube specimens of the same size and with the same boundary conditions. The results indicate the influence of H/D ratio, D/t ratio, and end-friction coefficient on the stress–strain distribution, dynamic compressive properties and failure modes of sub-scale concrete-filled steel tubes under impact load. The size-dependent behaviour of the CFST is found to be a function of the level of confinement the circumferential steel tube imposes on the concrete filling. Two expressions are proposed for predicting the DIF of yield stress for CFSTs: one considering the concrete–steel interaction relationship presented in Eurocode 4, and an empirical expression based on the Cowper–Symonds model for steel. The proposed rate- and size-dependent expressions show close correlations with experimental results.

Original languageEnglish
Pages (from-to)90-101
Number of pages12
JournalInternational Journal of Impact Engineering
Volume100
DOIs
Publication statusPublished - 1 Feb 2017
Externally publishedYes

Keywords

  • Boundary conditions
  • Concrete-filled steel tubes (CFST)
  • Confinement
  • Impact loading
  • Size dependency

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Automotive Engineering
  • Aerospace Engineering
  • Safety, Risk, Reliability and Quality
  • Ocean Engineering
  • Mechanics of Materials
  • Mechanical Engineering

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