Axial compression behavior of thin-walled steel partially encased fibre-reinforced self-compacting lightweight aggregate concrete columns

Abstract

This study presents the mixture design method of fibre-reinforced self-compacting lightweight aggregate concrete (FSLC) and combines it with cold-formed steel (CFS) to propose a novel thin-walled steel partially encased FSLC (TPEC) column. The axial compression behavior of the TPEC column was revealed by test and finite element analysis. The test results showed that FSLC did not experience brittle failure when constrained by CFS. The presence of FSLC in CFS also restricted the occurrence of buckling, resulting in improved ductile behavior of the TPEC columns. However, the connection between the web separated at the peak load, at which time the column no longer satisfied the requirements for the serviceability limit state. Finite element analysis demonstrated the transverse constraint effect of the thin-walled steel frame on FSLC, and through parametric analysis, more rational arrangements for web connections can be obtained. The cross-section of the TPEC column can be divided into three constraint zones based on the strength of the transverse constraint on the FSLC. A compressive strength calculation model for FSLC under the constraint of a thin-walled steel frame was proposed. A calculation method of the axial carrying capacity of the TPEC column was proposed, and the corresponding calculation model demonstrated better applicability.