Abstract
Concrete-filled steel tubular (CFST) columns are widely used in engineering structures, and they have many different cross section types. Among these, normal solid sections and concrete-filled double-skin steel tubular sections are often used. Although many studies have been conducted on CFST columns with these two section types, no studies have been conducted on their damage assessment under blast loading. In this study, experimental analysis and a numerical simulation method were integrated to evaluate the responses and assess the damage of two concrete-filled steel tubular (CFST) columns with different cross sections subjected to near-field blast loading. The results showed that for a scaled distance of 0.14 m/kg1/3, plastic bending deformation occurred on the surfaces of the two CFST columns facing the explosive. The antiexplosion performance of the normal solid-section (NSS) CFST column was better than that of the concrete-filled double-skin steel tubular (CFDST) column. The explosion centre was set at the same height as the middle of column, and the distributions of the peak pressure values of the two columns were similar: the peak pressures at the middle points of the columns were the greatest, and the peak pressures at the bottom were higher than those at the top. With the analysis of the duration of the positive pressure, the damage at the middle was the most severe when subjected to blast loading. Using pressure-impulse damage theory and the validated numerical simulations, two pressure-impulse damage evaluation curves for NSS and CFDST columns were established separately by analysing the experimental and simulation data. Finally, based on the two pressure-impulse damage evaluation curves, the two pressure-impulse damage criteria for these two different fixed-end CFST columns were defined based on the deflection of the surfaces facing the explosives. Furthermore, the mathematical formulae for the two different column types were established to generate pressure-impulse diagrams. With the established formulae, the damage of the CFST columns with these two cross section types can be evaluated. Damage to other similar CFST columns with different cross section types due to near-field blast loading can also be evaluated by this method.
Highlights
Concrete-filled steel tubular (CFST) columns are widely used in engineering structures because of their high bearing capacities, good plasticities, and high flexural stiffnesses, and their static mechanical properties have been researched widely
The modes of failure for column members can be divided into maximum displacement, maximum stress, maximum strain, and vertical residual bearing capacity [38, 39]. e main principle for determining the damage assessment criteria is that the characteristics of the CFST columns related to the criteria should be obtained by experimental or numerical simulation methods, and the criteria should be easy to use in practical projects
The dynamic responses and damage assessment of normal solid-section and concrete-filled double-skin steel tubular (CFDST) columns subjected to near-field blast loading were studied by means of an explosion experiment and numerical simulations. e following conclusions were obtained
Summary
Concrete-filled steel tubular (CFST) columns are widely used in engineering structures because of their high bearing capacities, good plasticities, and high flexural stiffnesses, and their static mechanical properties have been researched widely. E influences of the cross-sectional parameters on the ultimate bearing capacities of hollow concrete-filled steel tubular columns under axial loading and the effect of the hollow ratio on the stress-strain relation was analysed by Wang et al [2]. Guneyisi et al developed an effective prediction model by means of gene expression programming to evaluate the axial load carrying capacities of short CFST columns [3]. Based on the results of tests conducted by various researchers on 213 samples, two theoretical equations were derived for the prediction of the ultimate axial load strengths of CFST columns by Kumar et al [4]. Researchers have studied the dynamic responses of columns under explosion shocks and achieved many results. e relevant studies can be divided into three categories:
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