Test and analysis on the seismic performance of a steel truss-to-circular CFT column sub-assembly

•Connections between steel truss and CFT column were tested under cyclic loading.•Failure modes depended on relative strength between steel truss and CFT column.•The specimen damaged on the CFT column had more ductile performance.•Better seismic performance was obtained if CFT column was weaker than steel truss.

This paper presents an experimental and theoretical investigation on connection between steel truss and circular concrete-filled tubular (CFT) columns used for modern low-rise railway station platforms. Two full-scale cyclic tests were performed on connection sub-assembly and results showed that relative strength between the steel truss and column zone had a major effect on the subassembly's seismic performance and failure patterns. Results also indicated that a better deformability and energy dissipation capacity can be obtained if the column zone is slightly weaker than the steel truss. In addition, a simplified theoretical model was proposed to predict the experimental load–deformation histories and failure patterns. Satisfactory comparisons were observed.