8.Axial compression behavior of the square concrete-filledsteel tubular stub columns with initial concrete imperfections

Abstract:

To date，there has been a paucity of research on square steel pipe concrete members with hollowing defects． In light of this，four short square steel pipe concrete columns with hollowing defects were fabricated to conduct an axial compression performance test．The results indicate that the damage to the specimens with hollowing defects primarily occurs in the middle and upper part of． As therate of hollowing increases，the damage location gradually develops towards the region of hollowing，and the specimen’s load-bearingcapacity and ductile properties are reduced． However，when the rate of hollowing is less than 4． 25% ，the effect of the defects on thespecimen’s load-bearing capacity is not significant． However，when the rate of hollowing exceeds 4． 25% ，the impact of defects on thespecimen’s load-bearing capacity becomes substantial． Conversely，when the rate of hollowing is less than 4． 25% ，the effect of de-fects on the specimen’s load-bearing capacity remains negligible． For this particular type of hollowing，it is imperative to establish alimit value for hollowing between 4． 25% and 6． 25% ． In instances where the rate of hollowing exceeds this threshold，it is essential toimplement measures to ensure the collaboration of the steel pipe and the concrete．

Keywords: square concrete-filled steel tubular stub columns; initial concrete imperfections; axial compression behavior; experimentalresearch