Structural behaviour and reliability of CFST trusses with random initial imperfections
Structural behaviour and reliability of CFST trusses with random initial imperfections
复制标题
DOI：
10.1016/j.tws.2019.106192
复制
发表时间：
2019-10
影响因子：
6.4
通讯作者：
Silin Chen;C. Hou;Hao Zhang;Lin-Hai Han
中科院分区：
文献类型：
--
作者：
Silin Chen;C. Hou;Hao Zhang;Lin-Hai Han
钢管混凝土桁架是由钢管混凝土弦杆和空心管支撑组成的组合结构。钢管混凝土桁架越来越多地应用于塔、梁、墩、拱等大型结构中。由于在弦杆中填充混凝土，钢管混凝土桁架的抗压和抗弯性能比空心管桁架有很大的改善。钢管混凝土桁架结构由于其复杂的几何形状、非线性的材料相互作用和复杂的施工工艺，其初始缺陷对结构的强度和稳定性有很大的影响。以往的相关研究大多集中在钢管混凝土构件中单一类型的缺陷和假定的缺陷大小上，而实际上存在多种组合的钢筋和混凝土缺陷。基于现场实测数据和蒙特-卡罗（MC）模拟，建立了具有随机缺陷的钢管混凝土桁架可靠度非线性分析框架。建立了钢管混凝土桁架的非线性有限元分析方法，并通过试验数据验证了该方法的有效性。对具有确定性初始缺陷和概率性初始缺陷的钢管混凝土桁架的抗弯性能进行了评价和比较，并在此基础上提出了考虑随机初始缺陷的可靠度和相关的系统抗力系数。
Concrete-filled steel tubular (CFST) truss is a type of composite structure with CFST chords and hollow tubular braces. CFST trusses have been increasingly used in large-scale structures such as towers, bridge girders, piers and arch ribs. The compression and flexural behaviour of CFST trusses are greatly improved compared to hollow tubular trusses due to the concrete infill in chords. With the complex configuration, nonlinear material interaction and sophisticated construction process, initial imperfections may largely affect the strength and stability of a CFST truss structure. Relevant studies in the past mostly focused on one single type of imperfection with assumed magnitude in CFST member whilst in reality a variety of combinations of steel and concrete imperfection exist. This paper develops a nonlinear analysis formwork with the reliability analysis of CFST truss with random imperfections based on on-site measurement data and Monte-Carlo (MC) simulations. Advanced nonlinear finite element analysis (FEA) that can account for the material interaction and confinement in CFST trusses is established and validated by reported test data. The flexural behaviour of CFST trusses with deterministic and probabilistic initial imperfections are evaluated and compared, based on which the reliabilities and related system resistance factors in regards to random initial imperfections are proposed.