Li Mengyao, Hu Yi, Rao Lanzhe, Jiang Liqiang, Li Jingbin, Zhou Shizhong, Sun Hongyu, Peng Shi, Pang Xia, Chen Yuanjun, Hu Jun, Xie Ping
School of Civil Engineering, Central South University of Forestry and Technology, Changsha 410004, China.
Sichuan Provincial Engineering and Technology Research Center for Innovative Development of Bamboo Fiber Nutrition, Leshan 614000, China.
Polymers (Basel). 2025 Aug 30;17(17):2365. doi: 10.3390/polym17172365.
To overcome brittle failure in conventional cold-formed steel-concrete (CFS-C) corner columns, this paper used fiber-reinforced concrete to replace ordinary concrete, investigating failure mechanisms and performance through systematic numerical simulations. A finite element model (FEM) was established and validated by experiments, and the errors for ultimate capacity were within 10%. A series of numerical models was established for parametric analyses focusing on the effects of the parameters of polypropylene fiber (PF), carbon fiber (CF), steel fiber (SF), and bamboo fiber (BF) with different volume dosages and the thickness of cold-formed steel (CFS) on the axial compression ultimate capacity and corresponding displacement of CFS composite corner columns. The results indicated that (1) PF effectiveness was dependent on steel thickness: thicker steel suppressed micro-defects, activated the toughening potential of PF, and increased the ultimate capacity of the columns by 24.8%. (2) CF had a critical dosage of 0.4%: at this dosage, CF increased the column's ultimate capacity by 14.1% through stress redistribution, while when the dosage exceeded this value, fiber agglomeration caused a reduction in the column's strength, with a maximum decrease of 16.2%. (3) SF effectiveness showed a linear increase: at a dosage of 1.6%, SF formed a synergistic three-dimensional bridging network and generated a confinement effect, increasing the column's ultimate capacity by 36.5% and displacement by 92.2%. (4) BF mainly improved the ductility of columns: through crack bridging and pull-out energy dissipation, BF increased column displacement by 33.2%. (5) The modified Eurocode 4 formula could reduce the calculation error of ultimate capacity from 6.3% to within 1%. The findings guide optimal fiber selection and dosage in practice, promoting such columns' use in seismic and load-bearing structures.
为克服传统冷弯型钢混凝土（CFS-C）角柱的脆性破坏，本文采用纤维增强混凝土取代普通混凝土，通过系统的数值模拟研究破坏机制和性能。建立了有限元模型（FEM）并通过实验验证，极限承载力误差在10%以内。建立了一系列数值模型进行参数分析，重点研究了不同体积掺量的聚丙烯纤维（PF）、碳纤维（CF）、钢纤维（SF）和竹纤维（BF）以及冷弯型钢（CFS）厚度对CFS组合角柱轴向抗压极限承载力及相应位移的影响。结果表明：（1）PF的有效性取决于钢材厚度：较厚的钢材抑制微缺陷，激活PF的增韧潜力，使柱的极限承载力提高24.8%。（2）CF有一个临界掺量为0.4%：在此掺量下，CF通过应力重分布使柱的极限承载力提高14.1%，而当掺量超过此值时，纤维团聚导致柱强度降低，最大降幅为16.2%。（3）SF的有效性呈线性增加：在掺量为1.6%时，SF形成协同三维桥接网络并产生约束效应，使柱的极限承载力提高36.5%，位移提高92.2%。（4）BF主要提高柱的延性：通过裂缝桥接和拔出耗能，BF使柱位移提高33.2%。（5）修改后的欧洲规范4公式可将极限承载力的计算误差从6.3%降低到1%以内。研究结果为实际工程中纤维的优化选择和掺量提供了指导，促进了此类柱在抗震和承重结构中的应用。
