ANALYSIS ON BLAST-RESISTANT PERFORMANCES OF CONCRETE-FILLED STEEL TUBE COLUMNS CONFINED WITH FRP UNDER AXIAL COMPRESSION

In order to study the blast-resistant capacity of concrete-filled steel tube columns confined with fiber-reinforced polymer(FRP) under axial compression, the numerical simulations and analysis on the dynamic response of 16 axial compressive column specimens subjected to blast loads was calculated by finite element software ANSYS/LS-DYNA. And the effects of axial compression ratios, slenderness ratios, the pasting method of FRP sheets and the type of FRP sheets on the blast resistant capacity of specimens were studied by parametric analysis. The results showed that when the axial compression ratio was not exceed 0.5, the existence of axial pressure could improve the anti-detonation performances of the specimens, however, when the axial compression ratio was greater than 0.5, the existence of axial pressure greatly weakened the anti-detonation performances of the specimens. With the increase of slenderness ratios, the mid-span displacement of the specimens increased, and the blast resistant capacity decreased. Pasting FRP sheets could improve the anti-explosion performances of the specimens, and the specimens locally pasted FRP with reasonable design could achieve the constraint effect with those fully pasted. Under the condition that other parameters remained unchanged, pasting CFRP sheets was more effective in improving the blast-resistant performances of specimens than pasting GFRP sheets.