To examine the seismic behavior of Q690 high-strength (HS) steel in concrete-filled double skin steel tubular structures

a low cycle loading test was conducted on the circular-in-circular high-strength concrete-filled double skin steel tubular (HCFDST) columns with out-of-code diameter-to-thickness (D/t) ratios

for promoting the tendency of light weight and high strength in engineering structures.Key parameters including hollow ratios (χ=0.54～0.82)

axial compression ratios (n=0.1～0.3) and infill material types (ECC or concrete) were analyzed to investigate the influences on seismic performance.The results indicated that:Increasing the axial compression ratio and hollow ratio significantly impairs the hysteretic behavior

load-bearing capacity

and ductility of concrete-filled steel tubular column feet

whereas specimens with ECC materials exhibit poorer performance compared to those with conventional concrete.Overall

when the axial compression ratio

hollow ratio

and diameter-to-thickness ratio are appropriately controlled

Q690 high-strength concrete-filled double-skin tubular (CFDST) columns exhibit favorable hysteretic performance.This can serve as a valuable reference basis for their application in engineering projects such as offshore wind turbine support structures

jacket platforms

and high-piled wharves.