钢管混凝土-FRP管海水海砂混凝土组合柱轴压模型

Model for stress-strain curves of concrete filled steel tube-seawater and sea sand concrete filled FRP tube composite columns under axial load

提出一种钢管混凝土-纤维增强复合材料(FRP)管海水海砂混凝土(SWSSC)组合柱新型结构,其由外侧钢管、夹层普通混凝土、内侧FRP管和核心SWSSC构成。在轴向荷载作用下,夹层普通混凝土受到钢管的约束,而核心SWSSC受到钢管和FRP管的共同约束,考虑到两部分混凝土的不同约束机制,在现有的FRP-钢复合管约束混凝土的计算模型的基础上,本文提出了钢管混凝土-FRP管SWSSC组合柱的峰值点和极限点的计算模型;并利用FRP-钢复合管约束混凝土的应力-应变曲线模型,得到了钢管混凝土-FRP管SWSSC组合柱的应力-应变预测曲线;在72个钢管混凝土-FRP管SWSSC组合柱的轴压试验结果的基础上,对建议的模型进行了验证与评估。结果表明,提出的模型可以较好地预测钢管混凝土-FRP管SWSSC组合柱的应力-应变曲线。最后,利用提出的应力-应变曲线模型对钢管混凝土-FRP管SWSSC组合柱的轴压性能进行了参数化分析。

A novel structure termed as concrete filled steel tube-seawater and sea sand concrete(SWSSC)filled fiber reinforced polymer(FRP)tube composite columns was proposed,which was composed of outer steel tube,sandwiched ordinary concrete,inner FRP tube and core SWSSC.The sandwiched ordinary concrete was confined by the outer steel tube,while the core SWSSC was confined by both steel tube and FRP tube under axial compression.Considering the different confinement mechanism of two kinds of concrete,the calculation models of peak point and ultimate point of concrete filled steel tube-SWSSC filled FRP tube composite columns were proposed based on the existing calculation model of concrete-filled FRP-steel composite tube columns.And the predicted stress-strain curve model was obtained by using the stress-strain curve model of concrete-filled FRP-steel composite tube columns.The proposed model was verified and evaluated on the basis of the existing test results.The results show that the proposed model can predict the stress-strain curve of concrete filled steel tube-SWSSC filled FRP tube composite columns well.Finally,based on the proposed stress-strain model,the axial compression behavior of concrete filled steel tube-SWSSC filled FRP tube composite columns with different parameters was analyzed.