Li Biao, Ding Faxing, Lu Deren, Lyu Fei, Huang Shijian, Cao Zheya, Wang Haibo
Hunan Tieyuan Civil Engineering Testing Co., Ltd., Changsha 410075, China.
China Railway No. 3 Engineering Group Co., Ltd., Taiyuan 030001, China.
Materials (Basel). 2022 Jun 18;15(12):4313. doi: 10.3390/ma15124313.
With the development of new concrete technology, high-strength concrete has been used worldwide. In particular, more economic benefits can be achieved by applying high-strength concrete-filled steel tube (HSCFST) columns in the concrete core walls of super high-rise buildings. A constitutive relation with high applicability for high-strength materials with different strength grades is proposed. Based on this constitutive model, a brick element model of 181 sets of axially compressed square HSCFST members is established and experimentally verified. The effects of the concrete strength, diameter-to-thickness ratio, and steel yield strength on the axial compressive capacities of these members were investigated based on finite element calculation results. The results showed that with an increase in the concrete strength, the ultimate bearing capacities of CS-CC, HS-HC, HS-CC, and CS-HC stub column members increased by 60%, 24%, 44%, and 21% at most, respectively. Additionally, as the steel yield strength increased, the ultimate bearing capacities of CS-CC, HS-HC, HS-CC, and CS-HC stub column members increased by 8.8%, 5.1%, 8.5%, and 5.2%, respectively, Hence, material strength has the greatest impact on CS-CC and HS-CC. The confinement effect of the square steel tube on the concrete weakens as the strength grade of steel or concrete increases. Notably, the confinement effect of steel tube on the concrete is strongest in CS-CC and weakest in the CS-HC. In addition, the confinement coefficients of square HSCFST stub columns with different combinations of concrete and steel strengths were analyzed. Based on the superposition principle in the ultimate state, a practical axial compressive capacity calculation formula for three types of square HSCFSTs is established. Compared with existing major design code formulas, the proposed formula is more accurate and concise and has a clear physical meaning.
随着新型混凝土技术的发展，高强混凝土已在全球范围内得到应用。特别是在超高层建筑的混凝土核心筒墙体中应用高强钢管混凝土（HSCFST）柱，可获得更大的经济效益。提出了一种对不同强度等级高强材料适用性较高的本构关系。基于该本构模型，建立了181组方形HSCFST轴压构件的单元模型并进行了试验验证。基于有限元计算结果，研究了混凝土强度、径厚比和钢材屈服强度对这些构件轴压承载力的影响。结果表明，随着混凝土强度的提高，CS-CC、HS-HC、HS-CC和CS-HC短柱构件的极限承载力分别最多提高了60%、24%、44%和21%。此外，随着钢材屈服强度的提高，CS-CC、HS-HC、HS-CC和CS-HC短柱构件的极限承载力分别提高了8.8%、5.1%、8.5%和5.2%，因此，材料强度对CS-CC和HS-CC的影响最大。方形钢管对混凝土的约束作用随着钢材或混凝土强度等级的提高而减弱。值得注意的是，钢管对混凝土的约束作用在CS-CC中最强，在CS-HC中最弱。此外，分析了不同混凝土和钢材强度组合的方形HSCFST短柱的约束系数。基于极限状态下的叠加原理，建立了三种方形HSCFST实用的轴压承载力计算公式。与现有主要设计规范公式相比，该公式更加准确、简洁，物理意义明确。
