Research on Influence Law and Prediction Model of Core Concrete Defects on Creep of Concrete-filled Steel Tube Members
ZHANG Rongling1,2, HAO Zhaofeng1, WANG Qicai1, MA Lina1, LYU Wenda3, LI Wenbo4
1 School of Civil Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China 2 National and Local Joint Engineering Laboratory of Road and Bridge Engineering Disaster Prevention Technology, Lanzhou Jiaotong University, Lanzhou 730070, China 3 Lanzhou Railway Design Institute Co., Ltd., Lanzhou 730000, China 4 China Railway 21st Bureau Group Co., Ltd., Lanzhou 730070, China
Abstract: In order to reasonably predict the creep law of concrete-filled steel tube members containing defects, creep tests of concrete-filled steel tube under four defect conditions were carried out, and the applicability of different creep prediction models for concrete-filled steel tube members at home and abroad was analyzed. The results show that in the process of compression, the micro-cracks of concrete around the cavity defects constantly occur and expand, causing the dislocation and slippage of concrete and increasing the additional deformation of concrete-filled steel tube. The debonding defect hinders the stress redistribution between the steel tube and the core concrete, weakens the interaction between the steel tube and the concrete, and increases the creep deformation of the core concrete. In the absence of defect and cavity defect, the theoretical value calculated by ACI209 model is closest to the measured value of concrete-filled steel tube creep. In the case of deboning defect, the theoretical value calculated by B3 model is closest to the measured value of concrete-filled steel tube creep. According to different defect types, a modified model is proposed, which greatly improves the accuracy of creep prediction of concrete-filled steel tube (CFST).
张戎令, 郝兆峰, 王起才, 马丽娜, 吕文达, 李文波. 核心混凝土缺陷对钢管混凝土构件徐变影响规律及预测模型研究[J]. 材料导报, 2021, 35(4): 4099-4104.
ZHANG Rongling, HAO Zhaofeng, WANG Qicai, MA Lina, LYU Wenda, LI Wenbo. Research on Influence Law and Prediction Model of Core Concrete Defects on Creep of Concrete-filled Steel Tube Members. Materials Reports, 2021, 35(4): 4099-4104.
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